sissy nikolaou (mueser rutledge consulting engineers)
TRANSCRIPT
Team Leader: Sissy Nikolaou (Mueser Rutledge Consulting Engineers)
Editors: Sissy Nikolaou (Mueser Rutledge Consulting Engineers), Dimitris Zekkos (University of Michigan)
Dominic Assimaki (Georgia Institute of Technology), and Ramon Gilsanz (Gilsanz Murray Steficek)
Geotechnical Engineering Extreme Events Reconnaissance Association
Earthquake Engineering Research Institute Learning from Earthquakes
Applied Technology Council
UNIVERSITIES
AUTH: Aristotle University of Thessaloniki
Papazachos, C., Pavlides S., Chatzipetros A., Papathanassiou G., Valkaniotis S.
AUTH‐LSDGEE: Laboratory Soil Dynamics & Geotechnical Earthquake Eng
Pitilakis D., Karatzetzou A., Pitilakis K., Mouratidis K.
AUTH‐DSE: Division of Structural Engineering
Sextos A.
DUTH: Democritus University of Thrace
Klimis N., Psaroudakis M.
GATECH: Georgia Institute of Technology
Assimaki D.
HUA: Harokopion University of Athens
Parcharidis I.
NTUA: National Technical University of Athens
Gazetas G., Vintzilaiou E, Psycharis I., Mouzakis H., Beriatos T., Garini E.,
Papathanasiou A., Rouchotas K., Tsouras V.
ASPETE: School of Pedagogical and Technological Education
Pelekis P., Plevris V.
UCLA: University of California at Los Angeles
Stewart J.
UMICH: University of Michigan
Zekkos D.
UPATRAS: University of Patras
Athanasopoulos G., Dritsos S., Mylonakis G., Papantonopoulos C., Agapaki E.,
Batilas A., Karatzia X., Katsiveli E., Kitsis V., Lyrantzaki F., Skafida S.,
Theofilopoulou O., Vlachakis V.
UTH: University of Thessaly
Moretti M., Papadimitriou A.G., Tsopelas P.
INSTITUTIONS ‐ ORGANIZATIONS
EPPO‐ITSAK: Institute of Engineering Seismology & Earthquake
Engineering
Karakostas C., Lekidis V., Makra K., Margaris B., Morfidis K.,
Papaioannou C., Rovithis M., Salonikios T., Savvaidis A., Theodulidis N.
LEEPKA: 35th Ephorate of Prehistoric and Classic Antiquities
Petropoulos A.
NOA ‐ IG: National Observatory of Athens, Institute of Geodynamics
Kalogeras I., Melis N., Evangelidis C., Ganas A., Papanikolaou M.
EYDAP: Athens Water Supply and Sewerage Company
Papadakis K., Eleutheriou C.
COMPANIES
DIA: Diatonos Mechaniki
Pantelis F., Moschonas D., Sypsa K.
EF: Easy Facilities SA
Tsakalias G., Psychogiou A., Kopanos D.
GENG: GEOENGINEER
Dimitriadi V.
GMS: Gilsanz Murray Steficek, LLP
Gilsanz R., Kim E., Mugford J., Yang C., Rosenmann J.
MRCE: Mueser Rutledge Consulting Engineers
Nikolaou S., Pehlivan M., Iliadelis D., Lincoln L., Richins J., Antonaki N.,
Malek M., Deming P.
OTM: Omilos Technikon Meleton
Gazetas A.
ROUCH: (Freelance Professional Civil Engineer)
Rouchotas K., Rouchotas L.
National Science Foundation
Contributing Authors
Team Leader: Sissy Nikolaou (Mueser Rutledge Consulting Engineers) Editors: Sissy Nikolaou (Mueser Rutledge Consulting Engineers), Dimitris Zekkos (University of Michigan)
Dominic Assimaki (Georgia Institute of Technology), and Ramon Gilsanz (Gilsanz Murray Steficek)
Geotechnical Engineering Extreme Events Reconnaissance Association
Earthquake Engineering Research Institute Learning from Earthquakes
Applied Technology Council
UNIVERSITIES AUTH: Aristotle University of Thessaloniki Papazachos, C., Pavlides S., Chatzipetros A., Papathanassiou G., Valkaniotis S. AUTH-LSDGEE: Laboratory Soil Dynamics & Geotechnical Earthquake Eng Pitilakis D., Karatzetzou A., Pitilakis K., Mouratidis K. AUTH-DSE: Division of Structural Engineering Sextos A. DUTH: Democritus University of Thrace Klimis N., Psaroudakis M. GATECH: Georgia Institute of Technology Assimaki D. HUA: Harokopion University of Athens Parcharidis I. NTUA: National Technical University of Athens Gazetas G., Vintzilaiou E, Psycharis I., Mouzakis H., Beriatos T., Garini E., Papathanasiou A., Rouchotas K., Tsouras V. ASPETE: School of Pedagogical and Technological Education Pelekis P., Plevris V. UCLA: University of California at Los Angeles Stewart J. UMICH: University of Michigan Zekkos D. UPATRAS: University of Patras Athanasopoulos G., Dritsos S., Mylonakis G., Papantonopoulos C., Agapaki E., Batilas A., Karatzia X., Katsiveli E., Kitsis V., Lyrantzaki F., Skafida S., Theofilopoulou O., Vlachakis V. UTH: University of Thessaly Moretti M., Papadimitriou A.G., Tsopelas P.
INSTITUTIONS - ORGANIZATIONS EPPO-ITSAK: Institute of Engineering Seismology & Earthquake Engineering Karakostas C., Lekidis V., Makra K., Margaris B., Morfidis K., Papaioannou C., Rovithis M., Salonikios T., Savvaidis A., Theodulidis N. LEEPKA: 35th Ephorate of Prehistoric and Classic Antiquities Petropoulos A. NOA - IG: National Observatory of Athens, Institute of Geodynamics Kalogeras I., Melis N., Evangelidis C., Ganas A., Papanikolaou M. EYDAP: Athens Water Supply and Sewerage Company Papadakis K., Eleutheriou C.
COMPANIES DIA: Diatonos Mechaniki Pantelis F., Moschonas D., Sypsa K. EF: Easy Facilities SA Tsakalias G., Psychogiou A., Kopanos D. GENG: GEOENGINEER Dimitriadi V. GMS: Gilsanz Murray Steficek, LLP Gilsanz R., Kim E., Mugford J., Yang C., Rosenmann J. MRCE: Mueser Rutledge Consulting Engineers Nikolaou S., Pehlivan M., Iliadelis D., Lincoln L., Richins J., Antonaki N., Malek M., Deming P. OTM: Omilos Technikon Meleton Gazetas A. ROUCH: (Freelance Professional Civil Engineer) Rouchotas K., Rouchotas L.
National Science Foundation
Contributing Authors
DEDICATION
To the resilient people of Cephalonia
Το χάσμα π’ άνοιξ’ ο σεισμός ευθύς εγιόμισ’ άνθη.
Διονύσιος Σολωμός, «Εις τo θάνατο Κυρίας Αγγλίδας», Απ. 1, 150.3.1.
Where the quake scarred the earth, flowers will blossom in unison.
Excerpts from the poem «On the death of Ms. English», 1, 150.3.1.
by Dionysios Solomos, national poet of Greece, who was born and lived in the Ionian islands.
Acknowledgments ORGANIZATION AND FUNDING: GEER/EERI/ATC
The 2014 reconnaissance mission to Cephalonia, Greece was organized and supported
financially by the Geotechnical Extreme Event Reconnaissance (GEER) Association, the
Earthquake Engineering Research Institute (EERI), and the Applied Technology Council
(ATC). The background and resources for each organization are acknowledged below.
The work of the GEER Association, in general, is based upon work supported in part by
the National Science Foundation through the Geotechnical Engineering Program under Grant
No. CMMI-0825734. The GEER Association is made possible by the vision and support of the
NSF Geotechnical Engineering Program Directors: Dr. Richard Fragaszy and the late Dr. Cliff
Astill. GEER members also donate their time, talent, and resources to collect time-sensitive
field observations of the effects of extreme events.
The Earthquake Engineering Research Institute (EERI) is a nonprofit corporation whose
objective is to reduce earthquake risk by advancing the science and practice of earthquake
engineering, by improving understanding of impact of earthquakes on the physical, social,
economic, political, and cultural environment, and by advocating measures for reducing the
harmful effects of earthquakes. The reconnaissance mission was funded by EERI’s Learning
from Earthquakes (LFE) Program, which has been funded in large part by the NSF. LFE sends
out multi-disciplinary teams of engineers, earth and social scientists into the field to investigate
and to learn from the damaging effects of earthquakes.
The Applied Technology Council (ATC) is a nonprofit corporation with mission to develop
state-of-the-art, user-friendly engineering resources and applications for use in mitigating the
effects of natural and other hazards on the built environment. ATC also identifies and
encourages needed research, and develops consensus opinions on structural engineering issues
in a non-proprietary format, thereby fulfilling a unique role in funded information transfer.
ATC funded this reconnaissance mission as a case of potential importance to the structural
engineering design practice.
Any opinions, findings, and conclusions or recommendations expressed herein are the
authors’ and do not necessarily reflect the views of the above organizations, associations or
companies that supported this mission.
GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 i
EXTERNAL REVIEWERS
The technical information was significant in volume and potential impact in the earthquake
engineering community. The editors asked for support of external expert reviewers to provide
their feedback in the most technically important sections of the report. At the time of
completion of Version 1, parts of the external review process is in progress that will be
completed in the next version. The input of our external reviewers, experts in their field that
bring additional value to our report is gratefully acknowledged. They are listed below in
alphabetical order with the sections they have been reviewing:
Adda Athanasopoulos-Zekkos, Assistant Professor, Civil & Environmental Engineering, University of Michigan, Ann Arbor, USA (Section 8.2) George Bouckovalas, Professor, School of Civil Engineering, Department of Geotechnical Engineering, National Technical University of Athens, Greece (Sections 8.2, 8.4) Michael Constantinou, Professor, Department of Civil, Structural, and Environmental Engineering, University at Buffalo, and Deputy Director of Structural Engineering and Earthquake Simulation Laboratory (SEESL), USA (Chapter 11) Youssef Hashash, Professor & John Burkitt Webb Endowed Faculty Scholar, Dept. of Civil & Environmental Engineering, University of Illinois at Urbana-Champaign, USA (Section 8.1, Section 10.1) Nicos Makris, Professor, Department of Civil Engineering, Department of Structures, University of Patras, Greece (Chapter 9) Cheryl J. Moss, Senior Geologist, Mueser Rutledge Consulting Engineers, New York, NY USA (Chapter 6) Thomas D. O'Rourke, Thomas R. Briggs Professorship in Engineering, Department of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA (Chapter 10) Philip J. Richter, Principal, Mosaic Architectural Solutions, Orange County, CA, and past President of the Applied Technology Council (ATC), USA (Chapter 11) Constadino (Gus) Sirakis, Executive Director of Technical Affairs, New York City Department of Buildings, New York, NY, USA (Chapter 11) Chris Sklavounakis, Associate Vice President, HDR, New York, USA (Sections 8.5, 10.2) Christos Vrettos, Professor and Director of Soil Mechanics & Foundation Engineering, Technical University of Kaiserslautern, Germany (Chapter 7, Sections 8.3, 8.6, 8.7) Andrew Whittaker, Professor and Chair, Department of Civil, Structural, and Environmental Engineering, and Director of Multidisciplinary Center for Earthquake Engineering Research (MCEER), University of Buffalo, USA (Chapter 11) Aspasia Zerva, Professor, Civil, Architectural, and Environmental Engineering, Drexel University, USA (Chapter 7, Sections 8.1, 8.5).
GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 ii
FUNDING RESOURCES FOR GREEK TEAM MEMBERS
Funding for Greek members of our team has been provided by the following resources,
whose support is gratefully acknowledged.
The European Union (European Social Fund, ESF) and Greek national funds through the
Operational Program “Education and Lifelong Learning” of the National Strategic Reference
Framework (NSRF) - Research Funding Program Thales: Investing in knowledge society
through the European Social Fund has supported the participation of Professors Achilleas
Papadimitriou and Panos Tsopelas of the UTH, University of Thessaly (MIS 375618), and the
participation of Professor Nikos Klimis and Mr. Manos Psaroudakis of DUTH, Democritus
University of Thrace (ESF Project 85330). The DUTH members were also supported by the
Geotechnical Division of their Civil Engineering Department.
The research project “FORENSEIS” (Investigating Seismic Case Histories and Failures of
Geotechnical Systems), implemented under the "ARISTEIA" Action of the "Operational
Programme Education and Lifelong Learning" and co-funded by the European Social Fund
(ESF) and national resources, supported financially the participation of Professor George
Gazetas and his team from the National Technical University of Athens (NTUA).
The European Research Project "Strategies and tools for Real Time Earthquake Risk
Reduction (REAKT)," supported the participation of team member Dr. Dimitri Pitilakis and
his team from the Laboratory of Soil Dynamics and Geotechnical Earthquake Engineering of
the Aristotle University of Thessaloniki, under REAKT Grant No. 282862.
The Queens School of Engineering of the University of Bristol provided the travel funds
to Professor George Mylonakis of the University of Patras.
The Technical Chamber of Greece (TEE) supported the reconnaissance visits by Professors
George Bouckovalas and Ioannis Psycharis of NTUA.
COLLABORATING INSTITUTIONS, AUTHORITIES, INDIVIDUALS
Several organizations assisted this mission by being active participants or providing
information and support to our team. Their help was invaluable in making information
available rapidly and setting meetings with agency representatives. Their support is gratefully
acknowledged and we hope that this collaboration is the beginning of a long relationship with
our supporting GEER/EERI/ATC organizations. The Greek collaborating institutions are: GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 iii
The Hellenic Society of Earthquake Engineering (ETAM, eltam.org) is highly
acknowledged for their immense contribution to this reconnaissance study. ETAM
participation included President Kyriazis Pitilakis, Vice President Elli Vintzilaiou, Secretary
Anastasios Sextos, Board members George Gazetas and Ioannis Psycharis, and more than 20
members in the field reconnaissance and report preparation. ETAM was in constant contact
with the GEER/EERI/ATC team and provided valuable support.
The local (Cephalonia-Ithaca) chapter of the Technical Chamber of Greece (tee.gr)
supported our mission by providing technical information and facilitating communication with
local authorities. The dialogue between practicing engineers and researchers on regional design
and earthquake observations was very insightful.
The Cephalonia Police authority assisted in making the reconnaissance work safe and
organized our access to areas closed to general public by providing special tags to our members.
The Port Authority was instrumental in getting us to the island upon arrival to Greece, by
delaying the departure of the last ferry boat that would transfer USA team members R. Gilsanz
and S. Nikolaou to Cephalonia. Coordinating with team members from Easy Facilities, the
ferry captain Mr. Christos Moraitis was able to get appropriate permission from the National
Port Authority to hold the ferry schedule back. We are grateful for this help.
The Technological Educational Institute (TEI) of Cephalonia graciously provided their
facilities, including a large amphitheater that could host all our team for daily meetings at the
end of each day, which was essential. Communication of team members with the Greek Society
of Civil Engineers (ΣΠΜΕ, www.spme.gr) and the Greek section of the International
Association for Bridge and Structural Engineering (IABSE, iabse.gr) is appreciated.
EYDAP (ΕΥΔΑΠ), the Water Supply and Sewerage Company personnel collaborated with
our teams in the field and prepared a detailed report that is included in Chapter 10. EYDAP
teams to Cephalonia were supervised by the General Manager of Networks, Mr. Stefanos
Georgiadis, Deputy General Manager of Networks, Mr. Konstantinos Vougiouklakis, and CEO
Mr. Antonis Vartholomaios. Mapping services were provided by Vassilis Sapoulidis and
Angeliki Tzamakou with support by Gesfaira SA. This invaluable contribution was made
possible by the coordination of Mr. George Sachinis of EYDAP, to whom we are grateful.
Dr. Vassilis Bardakis, Professional Structural Engineer, kindly provided information
related to the “Mantzavinateio” Lixouri Hospital from his work on studying this structure. GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 iv
The employees of the Cephalonia branches of Eurobank and National Bank of Greece are
acknowledged for their productive cooperation under difficult conditions.
The insightful contribution in insurance-related matters of Mr. George Foufopoulos of
National Insurance Company of Greece (Εθνική Ασφαλιστική) is grateful acknowledged.
Ms. Dionysia Poulaki-Katevati, author of the book Cephalonia before the earthquake of
1953, was a priceless resource of knowledge. She kindly provided information and material
such as rare postcards and documents that gave a vivid picture of the architecture and
infrastructure of the pre-1953 island. We are indebted to Ms. Poulaki-Katevaki, whose hard
work, passion, and depth of knowledge for Cephalonia was inspiring.
DATA DISSEMINATION: STRONG GROUND MOTION, LIDAR, GEOSPATIAL
The following organizations that participated in the reconnaissance report provided
recorded strong ground motion data from their stations for use by the earthquake engineering
community. We are grateful for their contribution and sharing their data.
EPPO-ITSAK (Earthquake Planning and Protection Organization, oasp.gr - Institute of
Engineering Seismology and Earthquake Engineering, itsak.gr) provided their recorded
acceleration time histories, presented in Chapter 7. EPPO-ITSAK kindly acknowledges K.
Konstantinidou, MSc-IT, and the staff of the Technical laboratory of ITSAK. Civil engineer S.
Zacharopoulos and technicians A. Marinos and N. Adam contribute to the effective operation
of the EPPO-ITSAK strong motion network and assure its data transfer to the central computer
facilities in Thessaloniki.
NOA-IG (National Observatory of Athens, noa.gr – Institute of Geodynamics, gein.noa.gr)
provided their recorded acceleration time histories, presented in Chapter 7. The NOA-IG team
greatly appreciate the contribution of the NOA-IG's technicians to the operational reliability of
the accelerographic network.
The Geography Department of HUA (Harokopion University of Athens, geo.hua.gr)
provided the Remote Sensing Interferometry data prepared by team member Professor Isaak
Parcharidis, who acknowledges DLR for TerraSAR-X data provision.
Geoengineer.org, the international information service for geotechnical engineers,
committed IT resources (human and cyber-infrastructure) to facilitate the immediate data
mining, indexing, mapping and dissemination through a “clearinghouse” via the portal GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 v
mygeoworld.info. Mr. Ilias Giannoutsos and Mr. Kostis Tsantilas of the IT division of the
company were instrumental in this effort and are gratefully acknowledged.
GEER/EERI/ATC LEADERSHIP SUPPORT
The support and encouragement of the GEER/EERI/ATC leadership in our mission was
essential. Jonathan Bray and David Frost, GEER’s Steering Committee Chair and Member,
respectively; EERI LFE Chair Ken Elwood, Executive Director Jay Berger and Special
Projects Manager Marjorie Greene; and ATC Executive Director Chris Rojahn, all were
available around the clock while in Greece and during report preparation. GEER recorder
Christine Z. Beyzaei was instrumental in reviewing report material and posting information on
the web. We are grateful for their attention that went beyond the funding support.
GILSANZ MURRAY STEFICEK
Special gratitude to the Partners of Gilsanz Murray Steficek (GMS) who have supported
this effort by graciously providing engineering time, supporting staff and other resources,
particularly for the work of Mr. Ramon Gilsanz, Mr. Eugene Kim, Mr. Alberto Guarise, Ms.
Connie Yang and Mr. James Rosenmann. MUESER RUTLEDGE CONSULTING ENGINEERS
The Partners of Mueser Rutledge Consulting Engineers (MRCE) have graciously supported
this effort by providing engineering time and resources, and MRCE staff engineers volunteered
time. This included the field and office work of Dr. Sissy Nikolaou and participation in editorial
or authorship capacity of MRCE engineers Dr. Menzer Pehlivan, Mr. Dimitrios Iliadelis, Ms.
Lysandra Lincoln, Mr. Jesse Richins, Ms. Nonika Antonaki, and Dr. Mojtaba Malek.
Engineering support was provided by Mr. Kyriakos Barbagianis, Dr. Michael Law, Mr.
Edward Phelps, and Mr. Allan Amador. Ms. Cheryl Moss reviewed Chapter 6 and Mr. Adam
Dyer created sketches of Lixouri Port and Debosset geologic section in Chapter 8. The support
of MRCE in this mission and report is gratefully acknowledged.
PEOPLE OF CEPHALONIA
Last but not least, we are most grateful for the kindness of the people of Cephalonia. Under
difficult conditions, they opened their doors to us, shared their experiences, and provided us
with information of drawings and engineering calculations for their houses. We have been
touched and humbled by each and every one of them. GEER/EERI/ATC Cephalonia, Greece 2014 Acknowledgments Report Version 1 vi
GEER/EERI/ATC Cephalonia, Greece 2014 Table of Contents Report Version 1 vii
TABLE OF CONTENTS
Page
Dedication
Acknowledgments i
Table of Contents vii
List of Figures ix
List of Tables xlv
Chapter
Page
1 INTRODUCTION 1-1
2 CEPHALONIA ISLAND AND AREAS COVERED 2-1
2.1 Cephalonia island 2-1
2.2 Focus Reconnaissance Locations 2-7
3 GEER/EERI/ATC TEAM 3-1
4 DOCUMENTATION AND CONTRIBUTIONS 4-1
5 SEISMIC HISTORY AND HAZARD 5-1
5.1 Historical Earthquakes 5-1
5.2 Seismic Hazard Evaluation 5-16
6 GEOLOGY AND SEISMOTECTONICS 6-1
6.1 Geology and Geomorphology 6-1
6.2 Seismotectonics 6-11
7 SEISMOLOGICAL AND STRONG MOTION ASPECTS 7-1
7.1 First Main Event of January 26, 2014 7-2
7.2 Second Main Event of February 3, 2014 7-15
7.3 Remote Sensing Interferometry 7-19
8 GEOTECHNICAL OBSERVATIONS 8-1
8.1 Site effects 8-1
8.2 Liquefaction, Ports & Waterfront 8-17
8.3 Earth Retaining Structures 8-84
8.4 Landslides and Rock Falls 8-107
8.5 Bridges 8-125
8.6 Embankments and Landfills 8-132
8.7 Settlement and Soil-Structure Interaction 8-142
9 RIGID BLOCKS 9-1
9.1 Overview and Key Observations 9-1
9.2 Detailed Reconnaissance 9-15
9.3 Statistics of observed failures in cemeteries 9-29
10 INFRASTRUCTURE NETWORKS 10-1
10.1 Potable and Wastewater Networks 10-1
10.2 Transportation Road Network 10-16
GEER/EERI/ATC Cephalonia, Greece 2014 Table of Contents Report Version 1 viii
11 STRUCTURAL OBSERVATIONS 11-1
11.1 Main Structural Observations 11-1
11.2 Building Inventory and Construction Types 11-7
11.3 Damage Assessment 11-8
11.4 Typical damage patterns by construction type 11-12
11.5 Structural behavior based on seismic codes 11-24
11.6 Special cases of structural interest 11-38
11.7 Public Buildings 11-46
11.8 Churches 11-52
11.9 Nonstructural Components 11-63
12 COMMUNITY PREPAREDNESS & RESPONSE 12-1
13 CONCLUSIONS AND RECOMMENDATIONS 13-1
14 REFERENCES 14-1
GEER/EERI/ATC Cephalonia, Greece 2014 List of Figures Report Version 1 ix
List of Figures
Figure
Chapter 2 Page
2.1.1 Natural beauty of Cephalonia island (photo from web).
2-1
2.1.2 Maps showing Cephalonia island (a) in Europe and (b) in Greece
(nationsonline.org); and (c) map of the island showing the capital Argostoli
and the town of Lixouri (kefallonia.gov.gr).
2-2
2.1.3 Image of King Kefalos from the Greek mythology (keffyroots.com, left). Map
of the hypothesis that present-day Cephalonia was two islands and that the
Paliki Peninsula was ancient Ithaca (odysseus-unbound.org). Names shown are
hypothesized ancient names used by Homer (right).
2-3
2.1.4 Old Argostoli port sketch from book of travels by Andre Grasset de Saint-
Sauveur (1800).
2-4
2.1.5 St. George’s castle from 12th century A.C., standing today near Argostoli (web
photo).
2-4
2.1.6 Argostoli before the 1953 earthquakes (from virtual walkthrough, Pavlidis et
al., 2010).
2-6
2.1.7 Argostoli after the 1953 earthquakes (53vorini-gr). Social welfare stamps
issued by Greece after the1953 earthquakes are shown on the bottom right
insert (catawiki.com).
2-6
2.1.8 Myrtos bay beach.
2-7
2.1.9 (a) Stalagmitic cavern of Drogarati; (b) Melissani lake
(students.ceid.upatras.gr).
2-7
2.2.1 Cephalonia locations visited by the GEER/EERI/ATC reconnaissance teams.
Top map shows the main focus towns around the Paliki peninsula at the
western part of the island where most of the damage was observed. Bottom
map shows remaining towns at the eastern part, where minor or no damage was
identified.
2-9
Note: No figures are included in Chapters 1, 3, 4 and 13.
GEER/EERI/ATC Cephalonia, Greece 2014 List of Figures Report Version 1 x
Figure
Chapter 5 Page
5.1.1 Key seismotectonic features of the broader Aegean area. The Cephalonia
Transform Fault (CTF) is shown within the black rectangle (modified after
Scordilis et al., 1984).
5-1
5.1.2 Seismic hazard maps of Greece published in: (a) 1939; (b) 1995; and (c) 2001
(referenced in current Greek Seismic Code). Cephalonia region shown in
dashed green rectangle.
5-2
5.1.3 Epicenters of strong (M≥6.0) earthquakes at the broader area of Cephalonia
since 1469. Historical events in gray circles and instrument-based epicenters in
colored circles.
5-5
5.1.4 Effects of the earthquakes of June 1759 (from Albini et al., 1994).
5-9
5.1.5 Localities damaged by the whirlwind of 31 May [square] and by the
earthquake of July 1766 [circle] (from Albini et al., 1994).
5-10
5.1.6 Damage to Argostoli waterfront after the 1953 earthquakes (kefalonitikanea.gr,
2013).
5-14
5.1.7 Massive collapse of Cephalonia housing stock following the 1953 earthquakes
(web).
5-14
5.1.8 Temporary tents used to house thousands of homeless and serve as hospitals
for the injured under very difficult conditions after the 1953 earthquakes
(ionian-island.co.uk/greece).
5-14
5.1.9 Damage to the Argostoli obelisk monument “Kolona” (GPS coordinates
38°10'26.25"N, 20°29'45.59"E) following the 1953 earthquakes (ionian-
island.co.uk/greece). The monument was rebuilt. Its upper drum toppled after
the 2nd
event of 2014 (see Bridges Section 8.5 of this report).
5-15
5.1.10 Photograph of mother and child at Argostoli port following the 1953
earthquakes (t53vorini-gr.blogspot.com).
5-15
GEER/EERI/ATC Cephalonia, Greece 2014 List of Figures Report Version 1 xi
Figure
Chapter 6 Page
6.1.1 Geological zones of Greece including the External Hellenides zone which
includes the island of Cephalonia (modified from Himmerkus et al., 2007).
6-1
6.1.2 Simplified active plate tectonic activity. Black arrows indicate plate motions
relative to Eurasia and small white arrows show direction of internal extension
over the greater Aegean area (modified from Papazachos and Papazachou,
2003; also in GEER Report No. 013).
6-2
6.1.3 Generalized map of geotectonic units of Greece. In general, the zones are
younger moving towards West. The bedrock of Cephalonia consists of Ionian
and Pre-Apulian Units (IGME, 1985).
6-3
6.1.4 Neotectonic map of Cephalonia and Ithaca islands (modified from Lekkas et
al., 1996).
6-4
6.1.5 Topographical map of Cephalonia and Ithaca Islands, showing the main thrust
separating the Ionian (IU) and Pre-Apulian Units (PU). The brown-shaded area
(Pl-Pt) approximately marks the area covered by post-alpine (Lower Pliocene
to Holocene) sediments in Paliki peninsula (IGME, 1985).
6-5
6.1.6 Cephalonia and neighboring islands: (a) slope map and (b) slope direction map.
6-6
6.1.7 Main seismotectonic properties of the Aegean and surrounding regions. The
study area is indicated by a rectangle. CTF = Cephalonia Transform Fault
(modified from Karakostas et al., 2004).
6-7
6.1.8 Seismogenic sources (i.e., active fault zones) in Cephalonia and surrounding
areas, as mapped by the Gre.Da.S.S. team (Greek Database of Seismogenic
Sources, gredass.unife.it). Yellow rectangular shapes represent surface
projection of fault zones, and the arrows indicate the fault rake.
6-8
6.1.9 Argostoli port in 18th century (ionian-island.co.uk).
6-9
6.1.10 Argostoli port in 1901 (modified from Pavlidis et al., 2010)
6-9
6.1.11 Topographic map of Argostoli in 1948 (from Pavlidis et al., 2010)
6-10
6.1.12 Argostoli aerial photos in: (a) late 1940s (Pavlidis et al., 2010), (b) 2013
(Google Earth).
6-10
6.1.13 Lixouri port following the earthquakes of: (a) 1953 and (b) 2014.
6-11
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Figure
Chapter 7 Page
7.1.1 Epicenters of 1/26/14 1st mainshock (Mw7.1, red star), aftershock (Mw5.5,
yellow star) and 48-hour aftershocks (M ≥4.0) (source: Geophysical
Laboratory, AUTH). Instruments: EPPO-ITSAK accelerographs (yellow
squares); seismographs (pink triangles). NOA-IG accelerographs (green
squares) and permanent station VLS (green triangle). Focal mechanisms
(source: Columbia University) and preliminary seismic fault (by Dr.
Papaioannou, ITSAK) shown in red line.
7-2
7.1.2 Observed macroseismic intensities of the 1st mainshock event of 1/26/14
(EMSC, 2014).
7-3
7.1.3 Permanent accelerographic stations installed by EPPO-ITSAK, NOA-IG and
UPATRAS at epicentral distances up to 200 km. The epicenter of the 1st event
is shown in red.
7-4
7.1.4 Shakemaps for the 1st mainshock event of Mw7.1 in Cephalonia.
7-5
7.1.5 Acceleration, velocity and displacement time histories recorded at Argostoli
(ARG2) station (top). Corresponding response spectra of pseudovelocity PSV
and acceleration SA (bottom) for the 1st mainshock event of 1/26/14, 13:55
GMT (Mw7.1). Structural damping ζ = 5%.
7-9
7.1.6 Acceleration, velocity and displacement time histories recorded at Vasilikades
(VSK1) station (top). Corresponding response spectra of pseudovelocity PSV
and acceleration SA (bottom) for the 1st mainshock event of 1/26/14, 13:55
GMT (Mw6.1). Structural damping ζ = 5%.
7-10
7.1.7 Lixouri (LXRB) station recordings of acceleration (left), velocity (middle) and
displacement (right) time histories for the 1st mainshock event of 1/26/14,
13:55 GMT (Mw6.1).
7-11
7.1.8 Acceleration response spectra from the Lixouri (LXRB) station recordings of
Figure 7.1.7 (1st mainshock event of 1/26/14, 13:55 GMT, Mw6.1). Structural
damping 5%.
7-11
7.1.9 Sami Town Hall (SMHA) station recordings of acceleration (left), velocity
middle) and displacement (right) time histories for the 1st mainshock event of
1/26/14, 13:55 GMT (Mw6.1).
7-12
7.1.10 Acceleration response spectra from the Sami Town Hall (SMHA) station
recordings of Figure 7.1.9 (1st mainshock event of 1/26/14, 13:55 GMT, w6.1).
Structural damping 5%.
7-12
7.1.11 Peak Ground Acceleration (PGA) of the two horizontal components recorded
by all stations in the Greek network from the 1st event versus epicentral istance.
Blue lines show median and +one standard deviation (σ) of Ground Motion
Predictive Equation (GMPE) for Greece by Skarlatoudis et al., (2003). Red
circles are L(N) components and open circles are T(E) components.
7-13
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Figure
Chapter 7 Page
7.1.12 Acceleration response spectra of horizontal components of 1st event of 1/26/14
(Mw6.1) at Argostoli station (in red) and single record of 1/17/83 (M7.0) at a
station located 35 km from Argostoli (in blue). Structural damping ζ = 5%.
7-14
7.2.1 Acceleration time histories in two horizontal (E-W, N-S) and vertical
directions (Z) (top) and corresponding acceleration response spectra SA
(bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by
the UPATRAS Argostoli Port (38.180N, 20.490E) station during the 2nd
mainshock event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof.
Pelekis of ASPETE. Structural damping ζ = 5%.
7-16
7.2.2 Acceleration time histories in two horizontal (E-W, N-S) and vertical
directions (Z) (top) and corresponding acceleration response spectra SA
(bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by
the UPATRAS Fokata (38.127N, 20.527E) station during the 2nd
mainshock
event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof. Pelekis of
ASPETE. Structural damping ζ = 5%.
7-17
7.2.3 Acceleration time histories in two horizontal (E-W, N-S) and vertical
directions (Z) (top) and corresponding acceleration response spectra SA
(bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by
the UPATRAS Airport (38.119N, 20.506E) station during the 2nd
mainshock
event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof. Pelekis of
ASPETE. Structural damping ζ = 5%.
7-18
7.3.1 Study area captured by German satellite TerraSAR after the 2nd
event of 2/3/14.
7-19
7.3.2 Interferogram from ground surface deformation measurements between
January 28th and February 8
th (modified from Parcharidis, 2014).
7-20
7.3.3 Interferometer map of Cephalonia after 2nd
event (modified from NEA, 2014).
7-21
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Figure
Chapter 8 Page
8.1.1 Strong motion stations referenced in this section (LXR1, ARG2 and CHV1) on
the Cephalonia neotectonic map (modified from Lekkas et al., 1996).
8-1
8.1.2 Response spectra (5% damping) of two of the strongest records obtained
during the 2nd Cephalonia event, compared to two of the most widely
referenced near-field strong motion records of Takatori and Rinaldi from the
Kobe 1995 and Northridge 1994 earthquakes.
8-3
8.1.3 Geologic cross section at the port of Lixouri, revealing the low strength alluvial
deposits (CL) which may have contributed to the high recorded accelerations
(Geosymvouloi EPE, 2014).
8-4
8.1.4 Spectral Analysis of Surface Waves (SASW) testing location (top) and
generalized shear wave velocity, Vs, profile (bottom). Data from Pelekis
(2014).
8-6
8.1.5 (a) Elastic transfer function from rock outcrop to ground surface using the
generalized Vs profile of Fig. 8.1.4, and (b) Horizontal to Vertical Spectral
Ratio (HVSR) of the LXR1 recording of the 2nd event.
8-6
8.1.6 Acceleration response spectrum of E-W ground motion recording at ARG2
station of EPPO-ITSAK during the 2nd event for structural damping ζ of 5%.
8-8
8.1.7 Site response at station ARG2: (a) shear wave velocity Vs profile at the
adjacent Debosset bridge by Rovithis et al (see Section 8.5); (b) idealized Vs
profile; (c) HVSR at station ARG2 from both events (4 components); and (d)
theoretical linear elastic surface-to-rock outcrop transfer function at Debosset
bridge SW embankment.
8-9
8.1.8 Ground motion recordings of the 2nd event by a UPATRAS instrument placed
in the port of Argostoli (38.180N, 20.490E) following the 1st event (data
compiled by Prof. Pelekis of ASPETE).
8-11
8.1.9 Ground motion recordings of the UPATRAS station placed at Airport
(38.119N, 20.506E) during the 2nd event main shock (data compiled by Prof.
Pelekis of ASPETE).
8-12
8.1.10 Comparison of design acceleration response spectra obtained based on EC-8
and ASCE 7-05 design event for Cephalonia and Portland that are on
equivalent level of seismic hazard zoning.
8-14
8.1.11 Comparison of acceleration response spectra of recorded Cephalonia motions
at (a) LXR1, (b) CHV1, and (c) ARG2 stations with EC-8 design spectra.
8-15
8.2.1 The four main ports in the island of Cephalonia: Argostoli, Lixouri, Sami, and
Poros.
8-17
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Figure
Chapter 8 Page
8.2.2 Google Earth photo of the Lixouri Port Area (GPS coordinates 38.20o, 20.44
o).
8-18
8.2.3 Lixouri port movement following (a) Event 1 and (b) Event 2. (GPS
coordinates 38.198767o, 20.439533o). George Athanasopoulos of UPatras is
on the photo.
8-20
8.2.4 Temporary Exhibit: Quay wall of Lixouri port from postcard mailed in 1919
(Poulaki-Katevati, 2009). To be replace by Google Earth view of the quay
wall. (FIGURE PENDING, SO THAT IT CAN BE UPDATED ONCE THE
REST OF PHOTOS AND TEXT IS FINALIZED).
8-21
8.2.5 Soil ejecta with gravel size particles along the Lixouri port waterfont after
Event 2. Note gravel size particles in the ejecta (GPS coordinates 38.19873o,
20.43934o).
8-22
8.2.6 Soil ejecta with gravel size particles along the Lixouri port waterfont after
Event 2. Notice the gravel size particles in the ejecta. (GPS coordinates
38.19873o, 20.43934
o).
8-22
8.2.7 Typical liquefaction ejecta in Lixouri port [GPS coordinates: a-(38.197531o,
20.439784o), b-(38.19988
o, 20.43969
o), c-(38.19922
o, 20.43928
o), d-
(38.19873o, 20.43934
o), 2/8/2014].
8-23
8.2.8 Example of seafront crack opening at the port of Lixouri. Note large particle
size of the ejecta (38°11'55.38"N,20°26'20.98"E).
8-23
8.2.9 Extensive evidence of coarse-grained ejecta in the area of Lixouri port: a) at
quay wall (38°12'0.02"N, 20°26'22.62"E), and b) towards the first row of
buildings parallel to the shoreline (38°11'59.82"N, 20°26'21.76"E).
8-24
8.2.10 Remnants of liquefaction on the Lixouri coastal sidewalk (GPS coordinates:
38.199444, 20.439166).
8-24
8.2.11 Ejecta on Lixouri coastal sidewalk tiles (GPS coordinates: 38.199166,
20.439166).
8-25
8.2.12 Evidence of liquefaction at Lixouri coastal sidewalk (GPS coordinates:
38.199166, 20.439166).
8-25
8.2.13 Evidence of liquefaction at a Lixouri coastal sidewalk (GPS coordinates:
38.199166, 20.439166).
8-26
8.2.14 180 degrees panorama view of the displacement patterns at the Lixouri port in
location: 38°11'53.53"N, 20°26'22.23"E.
8-27
8.2.15 Example of the displacement patterns at the Lixouri quay wall (38°11'52.99"N,
20°26'22.48"E).
8-28
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Figure
Chapter 8 Page
8.2.16 Lateral displacement of the quay wall, and ejected liquefied soil. This is
abundant where the wall has not displaced horizontally due to the small
perpendicular wharf restraining it. (GPS coordinates: 38.199444, 20.439166).
8-28
8.2.17 Vertical displacement observed behind the wavefront (marked with the yellow
curve) and opening of a road-pavement joint (GPS coordinates: 38.199166,
20.439444).
8-29
8.2.18 Cracks in the road behind the quay wall and liquefaction remnants on the
sidewalk. (GPS coordinates: 38.199166, 20.439444).
8-30
8.2.19 Vertical displacement behind quay wall exposing water network pipes (GPS
coordinates: 38.199166, 20.439444).
8-31
8.2.20 Lateral displacement of the quay wall towards the sea (GPS coordinates:
38.199166, 20.439444).
8-32
8.2.21 Vertical settlement behind the quay wall reaching 70 cm (GPS coordinates:
38.199166, 20.439444).
8-33
8.2.22 Across the Plaza of National Resistance (shown in Fig. 8.2.2), damage
consisted mainly of lateral quay wall displacement and road cracks (GPS
coordinates: 38.199444, 20.439444).
8-34
8.2.23 Lateral quay wall displacement and road cracks in the southern part of Lixouri
port (GPS coordinates: 38.199444, 20.439444).
8-35
8.2.24 Settlement behind the quay wall (GPS coordinates: 38.199722, 20.439722).
8-35
8.2.25 Cracks in the southern part of the Lixouri port (GPS coordinates: 38.199722,
20.439722).
8-36
8.2.26 Settlement and cracks behind the quay wall (GPS coordinates: 38.199558,
20.439852).
8-36
8.2.27 Uneven surface settlement due to lateral spreading and liquefaction of the
wharf backfill (GPS coordinates: 38.199627, 20.440022).
8-37
8.2.28 Light brown color sand liquefaction ejecta (GPS coordinates: 38.200000,
20.440000).
8-38
8.2.29 Soil liquefaction remnants behind the quay wall and lateral displacement
towards the sea front (GPS coordinates: 38.200277, 20.439383).
8-39
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Figure
Chapter 8 Page
8.2.30 Cracks behind the wall and sand remnants of liquefaction ejecta (GPS
coordinates: 38.201050, 20.439297).
8-39
8.2.31 Auxiliary dock on quay wall, located to the north of main dock in the port of
Lixouri: (a) from 2011 archives
{http://www.panoramio.com/photo/3072045?source=wapi&referrer=kh.google
.com}; and after the 2nd event: (b) front and (c) back (38°12'1.39"N,
20°26'21.85"E).
8-40
8.2.32 Lateral movement in Lixouri port along section A-A’ of Fig. 8.2.2 being
measured by Tasos Batilas and Xenia Karatzia of the on 2/8/14 (GPS
coordinates 38.19842 o, 20.43956
o).
8-40
8.2.33 (a) Lateral spread in Lixouri port along section B-B’ and (b) movement of quay
walls (GPS coordinates: a-(38.20072o, 20.43920
o), b-(38.20077
o, 20.43940
o),
2/8/14).
8-41
8.2.34 Plot of cumulative horizontal displacement vs. distance from point A (as
shown in Fig.8.2.2) at Lixouri port.
8-42
8.2.35 Plot of cumulative horizontal displacement vs. distance from point B (as shown
in Fig.8.2.2) at Lixouri port.
8-42
8.2.36 Temporary Exhibit to be replace with Google Earth view of the Davraga Main
pier [to be added after text and remaining photos are finalized).
8-43
8.2.37 Example of liquefaction damage and lateral spreading at the most damaged
section of the main pier (38°12'5.12"N, 20°26'22.40"E).
8-45
8.2.38 Most damaged section of the main pier (38°12'3.32"N, 20°26'22.92"E).
8-46
8.2.39 Another section of the main pier that suffered damage (38°12'3.30"N,
20°26'23.02"E).
8-46
8.2.40 State of the main (Davraga) pier in Lixouri port (38°12'5.02"N,
20°26'21.73"E): (a) Before the 2 events, from 2011 archives
{http://www.panoramio.com/photo/59409701?source=wapi&referrer=kh.googl
e.com}; (b) After the 2nd event (38°12'5.02"N, 20°26'21.73"E).
8-47
8.2.41 Damage of quay wall in Davraga pier. Sailboats overturned (GPS coordinates:
38.201050, 20.439297).
8-48
8.2.42 Lateral spreading and differential horizontal displacement along the wall of the
Davraga main pier. Note the different wall width shown with white arrows
(GPS coordinates: 38.201436, 20.440202).
8-48
8.2.43 Horizontal displacement and rotation of wall of main pier (GPS coordinates:
38.201483, 20.439452).
8-49
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Chapter 8 Page
8.2.44 Vertical settlement behind the wall of photo 8.2.43 (GPS coordinates:
38.201397, 20.439511).
8-49
8.2.45 Southern side of the main pier, the only side where damage was observed. At
the northern side, the presence of large monoliths likely had a positive effect,
restricting lateral movement (GPS coordinates: 38.201666, 20.440000).
8-50
8.2.46 Lateral movement is greater behind the narrower wall of the main Lixouri pier.
(GPS coordinates: 38.201466, 20.440158).
8-50
8.2.47 Cracks along main Lixouri pier dock surface (GPS coordinates: 38.201486,
20.441266).
8-51
8.2.48 Rotation and lateral movement of main pier. Prof. G. Gazetas of NTUA shown
on top photo (GPS coordinates: 38.201269, 20.440977).
8-52
8.2.49 Vertical displacement of main pier marked with yellow arrow (GPS
coordinates: 38.201269, 20.440977).
8-53
8.2.50 Panoramic views of the eastern-most section of Davraga pier.
8-54
8.2.51 Main pier: (a) opening of horizontal joint; (b) monolith breakers constraining
lateral movement; (c) concrete slabs settlement; and (d) detail of vertical
settlement in yellow arrows (GPS coordinates: 38.201611, 20.442094).
8-55
8.2.52 State of eastern most section of main pier of Lixouri port: (a) from 2011
archives,
{http://www.panoramio.com/photo/49466386?source=wapi&referrer=kh.googl
e.com} with jack up drilling vessel that reportedly caused pier damage, and (b)
after the 2nd event (38°12'6.14"N, 20°26'32.08"E).
8-56
8.2.53 E-W cross section of eastern-most section of main pier of Lixouri Port. Data
collected by Kostas Rouchotas of NTUA team. Sketch by Adam Dyer of
MRCE.
8-57
8.2.54 N-S cross section of eastern-most section of main pier in Lixouri Port. Data
collected by Kostas Rouchotas of NTUA team. Sketch by Adam Dyer of
MRCE.
8-57
8.2.55 Detailed drawing of the sketch of Fig. 8.2.53 developed from data by Kostas
Rouchotas of NTUA team showing E-W cross section of eastern-most section
of main pier of Lixouri Port.
8-58
8.2.56 Detailed drawing of the sketch of Fig. 8.2.54 developed from data by Kostas
Rouchotas of NTUA team showing N-S cross section of eastern-most section
of main pier in Lixouri Port.
8-58
8.2.57 State of lighthouse at Lixouri breakwater tip: (a) from 2011 archive photo
{http://www.panoramio.com/photo/50853069?source=wapi&referrer=kh.googl
e.com}, and (b) after the 2nd
event (38°12'3.70"N, 20° 26'35.41"E).
8-59
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Chapter 8 Page
8.2.58 View of breakwater with the lighthouse (left: 38°11'53.97"N, 20°26'22.06"E;
right: 38°12'4.90"N, 20°26'37.09"E).
8-60
8.2.59 Detailed view of the light-house’s settlement (a) From an online picture dated
5/8/09; and (b) after the 2nd event (GPS coordinates: 38.200897, 20.443222).
8-60
8.2.60 Light house settlement views (GPS coordinates: 38.200897, 20.443222). 8-61
8.2.61 Southern part of Lixouri port that experienced only minor cracks (GPS
coordinates: 38.197944, 20.441044).
8-61
8.2.62 Land reclamation on the outer side of the southern marina prevented lateral
displacements of the shallow quay wall. The ejected liquefied soil on the
reclaimed land is abundant (GPS coordinates: 38.197944, 20.441044).
8-62
8.2.63 Settlement of the coastal road and cracks on road surface (GPS coordinates:
38.198372, 20.439483).
8-62
8.2.64 Detailed views of the south part of Lixouri port: (a) and (b) minor cracks
behind the wall, (c) shallow water level (GPS coordinates: 38.198158,
20.442222).
8-63
8.2.65 Sidewalk, pavement cracks and road settlement (GPS coordinates: 38.201102,
20.438855).
8-64
8.2.66 Liquefaction zones observed along Lixouri port (GPS coordinates 38.20o,
20.44o).
8-64
8.2.67 Old painting of Argostoli port, ca. 1757 (ref: Wikipedia).
8-65
8.2.68 Argostoli port after the 1953 earthquake, looking west from above the town
bridge (Bittlestone, 2005).
8-65
8.2.69 Argostoli quay wall damage after the 1953 event (Papathanassiou & Pavlides,
2011).
8-66
8.2.70 Panoramic view of the Argostoli port following the two 2014 seismic events.
8-66
8.2.71 Examples of soil craters and ejecta along the waterfront of Argostoli port [GPS
coordinates a-(38.18105o, 20.48955
o), b-(38.118118
o, 20.48954
o), c-
(38.180752°, 20.489990°), d-(38.17118o, 20.49600
o)].
8-67
8.2.72. Ejecta material outside the Customs Building of Argostoli where the UPatras
Geotechnical Engineering Laboratory strong motion station is located. [GPS
coordinates: a: (38.18010o, 20.48993
o), b: (38.17998
o, 20.48996
o)]
8-68
8.2.73 Evidence of ejecta in the Port Authority building area at Argostoli
(38°10'47.85"N, 20°29'24.42"E).
8-69
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8.2.74 Evidence of maximum height of ejected soil-water mixtures against the wall of
a Port Authority building at Argostoli (38°10'47.50"N, 20°29'23.43"E).
8-69
8.2.75 Rigid body rotation of a single story R/C frame building (at left) due to
differential liquefaction-induced settlements at Port Authority complex in
Argostoli (38°10'47.91"N, 20°29'23.47"E): (a) view towards the south, (b)
view towards the north.
8-70
8.2.76 Google Earth photo of the central dock of Argostoli port. Red arrows indicate
development of excessive cracking and lateral spreading.
8-71
8.2.77 Quay wall at dock of Argostoli port: (a) wall outward movement and (b) cracks
due to lateral spreading dated 2/9/14. GPS coordinates: a-(38.17955o,
20.48987o), b-(38.17955
o, 20.49011
o).
8-71
8.2.78 Outward movement of quay wall and vertical displacement in front of the main
Argostoli port dock measured by Tasos Batilas of UPatras (GPS coordinates
38.18024o, 20.49034
o, 9/2/2014).
8-72
8.2.79 (a) Photograph of lateral movement and (b) settlement of ground behind the
quay wall (GPS coordinates 38.18137o, 20.48980o, 9/2/2014).
8-72
8.2.80 Argostoli port cumulative horizontal displacement vs. distance from A (see
Fig. 8.2.75).
8-73
8.2.81 Liquefaction observations at Argostoli coastal area (GPS coordinates 38.17o,
24.49o).
8-73
8.2.82 Quay wall view south of the Argostoli Port Authority building complex: (a)
from 2011 archives
{http://www.panoramio.com/photo/57109645?source=wapi&referrer=kh.googl
e.com} and (b) after the 2nd event (38°10'45.96"N, 20°29'22.51"E).
8-74
8.2.83 Minor displacement of quay wall (GPS coordinates: 38.176938, 20.490008).
8-75
8.2.84 (a) Vertical settlement of the backfill soil and (b) signs of liquefaction on the
road surface (GPS coordinates: 38.179525, 20.489597).
8-75
8.2.85 Underwater view of a 30-cm gap between blocks in Argostoli quay wall.
8-76
8.2.86 Underwater view of 20-cm gaps between blocks in Argostoli quay wall.
8-76
8.2.87 Underwater view of scour under base block in Argostoli quay wall.
8-76
8.2.88. Visible evidence of soil liquefaction at southeast part of Argostoli port (GPS
coordinates: 38.171197, 20.495725).
8-77
8.2.89 Sand boils on the free surface, southeast part of Argostoli port (GPS
coordinates: 38.171100, 20.495930).
8-78
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8.2.90 Sand boils on the free surface in the southeast part of Argostoli port (GPS
coordinates: 38.171166, 20.496000).
8-79
8.2.91 Port of Sami. Detailed damage shown on Fig. 8.2.92 for the area in lower
annotated circle, and in subsequent figures for the upper circle area which
experienced more significant damage.
8-80
8.2.92 Post-earthquake damage observation in the lower annotated circle area of Fig.
8.2.91 at the Sami port.
8-80
8.2.93 Crack following the 2nd event at Sami port main pier (38°15'14.97"N,
20°38'50.56"E).
8-81
8.2.94 Joint opening between blocks at Sami port pier with possible ejected sandy soil
material at the deepest water area of the pier. This was the only location where
these questionable sandy ejecta were identified (38°15'14.93"N,
20°38'51.60"E).
8-81
8.2.95 Evidence of liquefaction in Soulari (38,18996; 20,41198).
8-82
8.2.96 (a) Evidence of liquefaction in Kounopetra (38,15726; 20,38534). (b) Ground
cracking with limited evidence of sand boils in a field between Atheras and
Livadi (38,298547; 20,418600).
8-82
8.3.1 Geographical distribution of 36 retaining wall failures following the 1st and
2nd events. Original figure shows stone masonry retaining walls (to be updated
in next version).
8-85
8.3.2 Retaining wall and historical church at Havriata village: (a) before the 2 events,
(b) following the 1st event; and (c) following the 2
nd event; (38°10'57.52"N,
20°23'13.61"E). Photo (a) is from 2007 archives:
http://www.panoramio.com/photo/57109645?source=wapi&referrer=kh.google
.com.
8-86
8.3.3 Schematic of the Panayia Agriliotissa Church, prepared by S. Valkaniotis
(modified from Papathanasiou et al., 2014).
8-87
8.3.4 View of the retaining wall and church (a) from the southwest; and (b) from the
south following the 2nd event (38°10'57.52"N, 20°23'13.61"E).
8-88
8.3.5 Closer views of the damaged wall (GPS coordinates: 38.182500, 20.387222).
8-88
8.3.6 View of the masonry retaining wall, just downhill of the three-tiered plastered
masonry wall in Havriata (38°10'57.52"N, 20°23'13.61"E).
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8.3.7 Extensive failure of stone masonry retaining wall followed by road
embankment sliding failure with horizontal and vertical displacement. This
major failure is on the roadway connecting the villages of Vouni and Havriata
(38.177692°N, 20.397458°E). The reinforced concrete retaining wall shown in
yellow dotted circle suffered no damage although adjacent to the collapsed one.
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8.3.8 a) Collapse of lower two levels of a three-level stone retaining wall supporting
the bearing soil of a Vouni village church (38.177578o N, 20.403477
o E) after
the 2nd
event, and (b) partial collapse of the same wall following the 1st event.
8-90
8.3.9 Single-story building close to Kouvalata village (38.234484° N, 20.419554°
E): (a) failure of stone masonry retaining wall followed by local landslide of
the supporting bearing soil after the 1st event, and (b) progression of failure
after the 2nd
event.
8-90
8.3.10 Damage at Kourouklata village church. (a) cracked ground in foreground with
wall to the right and church in background; (b) ground deformations taken by
Prof. Athanasopoulos, V. Kitsis and O. Theofilopoulou; (c) damage at
cemetery behind the church; (d) concrete wall adjacent to masonry wall from
lower elevation; and (e) view of wall damage (38°14'31.72"N, 20°28'25.40"E).
8-92
8.3.11 Lateral soil movement, at Kourouklata’s church frontyard (38.242113,
20.473955).
8-93
8.3.12 Vertical settlement of 20 cm behind the retaining wall (38.242113, 20.473955).
8-93
8.3.13 Masonry wall damage towards Kourouklata village. (38°14'26.29"N,
20°28'35.14"E)
8-94
8.3.14 Another masonry wall damage towards Kourouklata village (38°14'26.29"N,
20°28'35.14"E).
8-94
8.3.15 Retaining wall failures at several locations in Kourouklata village
(38.241075N, 20.475602E).
8-95
8.3.16 Collapse of stone retaining wall in Kourouklata village. (38.241797,
20.473677).
8-95
8.3.17 (a) Extensive failure of stone masonry retaining wall followed by road
embankment settlement close to Atheras Village (38.293224°N, 20.45217°E)
after 1st event; (b) failure at 3
rd wall location after 2
nd event with adjacent
concrete sections undamaged; (c), (d), (e) failure details.
8-96
8.3.18 Failure of a short masonry wall near Argostoli (38°10'50.76"N, 0°29'54.01"E).
8-98
8.3.19 Failure of masonry wall supporting roadway outside of Lixouri
(38°12'21.05"N; 20°24'54.89"E).
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8.3.20 (a) View of stone/masonry retaining wall failure at the cemetery of Livadi
village. (b) Close-up photo showing rotation of the wall face and tension cracks
in the backfill (GPS coordinates: 38.255833, 20.420833).
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8.3.21 Collapsed retaining wall at cemetery of Lixouri with close up (b-c) side views
(GPS coordinates: 38.192400, 20.438725); (d-e) top views (38.192433,
20.438725).
8-100
8.3.22 Failure of a small retaining wall at the back yard of the Lixouri cemetery’s
church (GPS coordinates: 38.192911, 20.438625).
8-101
8.3.23 Partially failed small retaining wall in the backyard of the Theotokos
Kipouraion Monastery (38.203194, 20.348219); (b, c): View from the
backyard: collapse of retaining wall marked with red circle. (38.203327,
20.347747).
8-101
8.3.24 Retaining wall collapse in front of the “new” Aghia Thekla church (GPS
coordinates: 38.245202, 20.384422).
8-102
8.3.25 Damage of stone walls in Aghia Thekla village (GPS: 38.245202, 20.384422).
8-102
8.3.26 The old Aghia Thekla church (GPS coordinates: 38.244894, 20.386097).
8-103
8.3.27 A small retaining wall failure at the old Aghia Thekla church cemetery (GPS
coordinates: 38.244944, 20.386433).
8-103
8.3.28 Failure of concrete retaining wall along a cold joint. The upper and lower
portions of the wall appear to have been built at different times (38°11'0.07"N;
20°22'54.18"E); (a, b) side views; (c, d) top view with tensile cracks of soil
surface at hill top where the strong motion station is located.
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8.3.29 Cracked pavement due to wall movement with retaining wall on the left.
(38°10'57.83"N, 20°23'9.40"E).
8-105
8.3.30 Tilted cantilever retaining wall of variable height on the roadway between
Havdata and Lixouri (38°12'21.05"N, 20°24'54.89"E).
8-105
8.4.1a Locations investigated (AT: Mt. Ainos Thrust, AEF: Aghia Ephymia Fault).
8-107
8.4.1b Cephalonia path on 2/8/14 (black), 2/9/14 (red) of Paliki Peninsula and
Argostoli Bay by UPatras team. Geographical distribution of rock falls (yellow
points) and road embankment settlements (blue points).
8-108
8.4.1c Cephalonia path on 2/8/14 (black), 2/9/14 (red) of Atheras (south of Paliki
Peninsula) and Myrtos Bay by UPatras team. Geographical distribution of rock
falls (yellow points) and road embankment settlements (blue points).
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8.4.1d Cephalonia path on 2/17/14 (green) on the eastern part of Cephalonia by
UPatras team. Geographical distribution of rock falls (yellow points).
8-109
8.4.2. Rock slope failure in limestone in Monastery of Theotokou Kipouraion
(38.202517° N, 20.348083° E, (a) UPatras team,2/9/14, (b) NTUA team,
2/10/14).
8-110
8.4.3. Numerous weathered rock landslides/rock falls along the shore near Monastery
of Theotokou Kipouraion. (38.203327° N, 20.347747° E, NTUA team,
2/10/14)
8-111
8.4.4. Rock fall with debris slide in steep cliffs in Platia Ammosbeach (38.213883°N,
20.353017° E, UPatras team, 2/9/14).
8-111
8.4.5 Rock failure of conglomeratic or breciatic limestone on a cut slope between
Moussata & Vlachata villages on the Poros- Argostoli road axis (38.126874°
N, 20.616777° E, DUTh, 2/22/14).
8-112
8.4.6. Rock slides in red consolidated conglomerate formations recorded at (a)
Northern part of Argostoli bay close to Kardakata Village (38.280957°N,
20.445637°E) and (b)road network between Argostoli and Sami village
(38.205687° N,20.607155° E, ITSAK team, 1/28/14).
8-112
8.4.7. Rock slides in cracked limestone formations recorded atNorthern part of
Argostoli bay following the (a) 1st event(38.287065° N, 20.448024° E) and (b)
2nd event (38.287018° N, 20.448027° E). Photos by ITSAK team on
1/28/14(a) and 2/10/14(b).
8-112
8.4.8. Disaggregated slides with debris flow observed at the Petani shoreline
(38.261705° N, 20.380166° E). Photo by NTUA team, 2/9/14.
8-113
8.4.9. A shallow rock slide of a weathered and fragmented limestone with debris flow
(38.251408° N, 20.466813° E, (a) Date of picture taken by DUTh team is
2/22/14, and (b) by UPatrasteam is 2/8/14)along the local road from
Kourouklata to Kontogourata).
8-114
8.4.10. Rock failures (mostly planar slides along limestone’s bedding and only
occasionally wedge failures) along roadcuts on the way from Kardakata to Zola
village in Aghia Kyriaki bay area (from 38.287181° N, 20.457548° E
to38.310356° N, 20.469258° E, DUTH team, 2/22/14).
8-114
8.4.11. Northern cliffs and eastern slopes of Myrtos Bay. Major wedge failure, shallow
rockslides and raveling; detachment and rolling down of the two major rock
blocks with the associated road pavement damage (38.337833° N, 20.532317°
E,UPatras, 2/10/14).
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8.4.12. Roll paths A and B of the two rock blocks of estimated volume of 500 m3 each
at Myrtos Bay (38.337833°N, 20.532317°E, ITSAK team, 2/19/14).
8-116
8.4.13. Possible trajectory of a limestone boulder of about 2 m3 that rolled over a
natural slope and bounced at least 3 times, passing through a tile roof of a
house in Athera village. Tracks of striking points where boulder bounced also
shown (38.317365° N, 20.418548° E, DUTh team, 2/22/14).
8-117
8.4.14. Shoreline of Xi area (from 38.159537° N, 20.410148° E to 38.160405° N,
20.413083° E) south of the Paliki peninsula where an extended slide (almost
250 m long) of a sandy marl escarpment was observed (ITSAK team,
02/19/2014).
8-117
8.4.15. Rock slope failure in road cut with gabions in fractured/weathered limestone.
Detached rock block crossed the road. (eastern part of island: 38°11'33.51"N,
20°40'39.04"E, UPatras, 2/19/14).
8-118
8.4.16. Rock slope failure in a road cut with gabions in weathered fractured
limestones. (eastern part of island, 38°11'52.99"N, 20°40'21.80"E, UPatras
team, 2/19/14).
8-118
8.4.17. Major earth landslide in Soulari (38°11'5.66"N,20°24'57.82"E, UPatras,
2/17/14.
8-119
8.4.18 Plane view of the incipient landslide failure.
8-120
8.4.19. Area showing signs of incipient earth landslide failure. (a) Cracks on upper
road pavement (UPatras) and (b) stone retaining walls destruction after the 1st
and 2nd events (ITSAK), and soil displacements at the toe (coordinates
38.293224°N, 20.45217°E, date 2/8/14).
8-120
8.4.20. Crest of circular type of slope movement on a 15 m high hill near Soulari
village (38°11'19.73"N, 20°24'45.10"E), with slippage towards the East
direction, (date 9/2/14).
.
8-121
8.4.21. Small landslides in stiff-clayey slopes, 400 m outside Soulari village.
(38.184444° N, 20.411388° E, NTUA team, 2/10/14).
8-121
8.4.22 Road embankment settlement near bridge in Havdata (38.2028° N, 20.40445°
E, U-Patras team, 2/9/2014)
8-122
8.4.23. Road embankment settlement in Chavriata (38.182733°N, 20.384067°E, date
2/9/14). Measurements by UPatras team members Eva Agapaki, Elpida
Katsiveli, and Costas Papantonopoulos.
8-123
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8.4.24. Road network connecting Havriata and Vouni villages at the south part of the
Paliki peninsula (38.17856° N, 20.40081° E); extensive road cracking and road
embankment failure observed, respectively, after the: (a) 1st and (b) 2nd
events. Photos by ITSAK team on 1/28/14 (a) and 2/5/14 (b).
8-123
8.5.1 Locations of bridges inspected during reconnaissance and described in this
section; the figures referenced correspond to the figure numbers of this section
(for example, Figure 2 stands for Figure 8.5.2).
8-125
8.5.2 Havdata bridge (38°12'10.30"N, 20°24'16.05"E): (a) western access
embankment and (b) eastern access embankment.
8-126
8.5.3 Havdata bridge (38°12'10.30"N, 20°24'16.05"E): Side view of outward
(downstream) displacement of southern retaining wall of western access
embankment.
8-127
8.5.4 Havdata bridge (38°12'10.30"N, 20°24'16.05"E). Side view of connection of
southern pier to deck-beam sections of the bridge.
8-127
8.5.5 Debosset bridge connecting the Drapano and Argostoli shorelines (GPS
coordinates 38°10'26.25"N, 20°29'45.59"E). Photo taken prior to the 1953
earthquakes (Poulaki-Katevati, 2009).
8-128
8.5.6. (a) Geotechnical and geophysical test locations along Debosset bridge, and (b)
geologic section revealing soil profile along the line B1-B2 shown in (a)
(sketch created by Adam Dyer of MRCE based on Pitilakis et al., 2006).
8-129
8.5.7 (a) Debosset bridge (38°10'26.25"N, 20°29'45.59"E); (b) Rehabilitated bridge
with no observed damage following the major events of 2014; (c) Multi-drum
obelisk (Kolona) monument intact after the 1st event; and (d) Toppling of
upper drum of the obelisk induced by the 2nd event.
8-130
8.5.8 Obelisk “Kolona” monument (GPS coordinates 38°10'26.25"N,
20°29'45.59"E) in early 1900’s sketch (Poulaki-Katevati, 2009). The upper
drum toppled after the 2nd 2014 event (Fig. 8.5.7d).
8-130
8.5.9 Observed failures adjacent to the Debosset bridge: permanent lateral
displacement of the quay wall and settlement of the backfill induced by: (a) 1st
event and (b) 2nd
event.
8-131
8.6.1 Locations of road embankments inspected during reconnaissance and described
in this section. Figures referenced correspond to section figure numbers (e.g.,
Fig. 2 stands for Fig. 8.6.2).
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8.6.2 Location A (38°10'42.84"N, 20°24'2.96"E) on the road connecting the Havriata
and Vouni villages. (a) Circular type of sliding observed after the 1st event. (b)
Embankment failure that affected the whole width of the road after the 2nd
event.
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8.6.3 Location B (38°10'39.79"N, 20°23'50.90"E) on the road connecting the
Havriata and Vouni villages. Severe road embankment damage was observed.
Photos taken after the 2nd event.
8-134
8.6.4 Off-Kardakata road embankments at an inter-distance of 160 m after 2nd
event: a) masonry wall collapse in NS direction (38°17'34.61"N,
20°27'8.16"E), b) masonry wall collapse in EW direction (38°17'30.81"N,
20°27'11.80"E).
8-135
8.6.5 Overview of the broader area of the off-Kardakata road embankment failure of
Figure 8.6.3b (38°17'30.81"N, 20°27'11.80"E): a) after the 1st event and, b)
after the 2nd event.
8-136
8.6.6. Cracks and settlements on the road embankment between Aghios Dimitrios
and Livadi villages (38°14'17.17"N, 20°25'44.30"E): (a) after the 1st (left) and
(b) the 2nd
(right) event.
8-137
8.6.7 North of Soularoi road embankment sliding, as viewed from the pavement
(38°11'21.51"N, 20°24'45.80"E).
8-137
8.6.8 South of Soularoi road embankment failure due to slope sliding
(38°10'43.69"N, 20°25'13.87"E).
8-138
8.6.9 Pavement cracks and settlement at the edge of the road embankment located at
38°17'8.28"N, 20°27'8.25"E close to Katochori village. Photo was taken after
the 1st event.
8-139
8.6.10 Kourouklata road embankments: a) lower altitude masonry wall collapse
(38°14'23.77"N, 20°28'30.29"E), b)higher altitude masonry wall collapse
(38°14'28.20"N, 20°28'24.87"E) (also visible in a, is the failed bell tower of
Kourouklata.)
8-140
8.6.11 The location of the two adjacent Cephalonia landfills (38°10'57.52"N,
20°23'13.61"E).
8-141
8.6.12 View of the (a) unlined landfill (vegetated, in the background; 38°18'33.15"N,
20°26'30.44"E) and (b) lined landfill (38°18'36.94"N, 20°26'29.02"E).
8-141
8.7.1 Locations of the 10 structures inspected during reconnaissance for SSI and
settlement effects. Additional cases documenting structural damage are
presented in the Chapter 11.
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8.7.2 Case 1: 3-story structure at the corner of Nestoros and Megalou Alexandrou
Streets (GPS Coordinates 38°11’45.50”N, 20°26’18.84”E, 2/18/2014).
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8.7.3 Typical 2-story building with no damages due to settlements. The pavement
suffered significant displacements (GPS Coordinates: 38°12’7.47”N,
20°26’12.99”E, 2/18/14).
8-144
8.7.4 Case 3: Lixouri Branch of Piraeus Bank (38°12’7.65”N, 20°26’19.70”E,
2/18/14).
8-145
8.7.5 Case 4: St. Nicholas Church Bell tower location (GPS coordinates
38°12'9.43"N, 20°26'17.63"E, 2/18/2014).
8-146
8.7.6. Case 4: St. Nicholas Church Bell Tower differential settlement (38°12'9.43"N,
20°26'17.63"E, 2/18/14).
8-147
8.7.7 Case 5: Power transformer pillar differential settlement (38°11'55.63"N,
20°26'20.56"E, 2/19/14).
8-148
8.7.8 Case 6: Café “Aen Plo” location and street view (38°12'3.52"N, 20°26'20" E,
2/19/14).
8-149
8.7.9 NE corner of Café “Aen Plo” NE corner ground failure (2/19/14).
8-149
8.7.10 Case 7. Ground settlement in the perimeter of 2-story R/C building south of
Lixouri. Location at the top part of this figure (GPS Coordinates
38°11'36.08"N, 20°26'19.90"E, 2/19/14).
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8.7.11 Case 8: Kechrionos Monastery. Shear failure on external gate (left) and
rotation of exterior lights (right), both along the EW direction (38°13'26.19"N,
20°25'43.36"E, 2/8/14).
8-152
8.7.12 Orientation of structural and non-structural damage relative to the EW
direction. (38°13'26.19"N, 20°25'43.36"E, 2/8/14). Insert: the 3 components of
spectral accelerations in the 2nd event.lined landfill (38°18'36.94"N,
20°26'29.02"E).
8-153
8.7.13 Comparison of the external and main gate of the Kechrionos Monastery prior
(left) and after the 2014 earthquakes (right).
8-153
8.7.14 Case 8: Kechrionos Monastery. Out-of-plane collapse of non-structural
elements (left). Close view of the main gate pillar dislocation together with
diagonal cracks of the external masonry.
8-154
8.7.15 Case 9: National Bank of Greece, Lixouri Branch located in the front row of
buildings parallel to the shoreline (GPS Coordinates: 38°12’7.8”N,
20°26’19.8”E)
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8.7.16 Case 9: Observations of deformations of the: (a) ground; (b) sidewalk
connection to base of building; and (c) cabinets of interior EW wall. (GPS:
38°12’7.8”N, 20°26’19.8”E, 2/9/14).
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8.7.17 Case 9: Summary of vertical (exaggerated) deformations between base of
building and its connection to the sidewalk along the façade of the bank. (GPS:
38°12’7.8”N, 20°26’19.8”E, 2/9/14).
8-155
8.7.18 Case 10. Locations of the 3-story structures designed with the latest seismic
code EAK2000. (GPS coordinates 38°13'48.19"N, 20°25'53.20"E, 2/9/14).
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8.7.19 Cases of buildings designed to EAK2000 experienced no damage to their load
bearing system due to multiple sources of over-strength. Possible beneficial
effects of SSI could have played a factor and should be studied further
(38°13'48.19"N, 20°25'53.20"E, 2/9/14).
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9.1.1 Locations of 27 cemeteries inspected during reconnaissance.
9-1
9.1.2 Overturning of the headstone in Lixouri cemetery taken on 2/9/14 by NTUA
team. [GPS coordinates: 38.192586, 20.438769]
9-3
9.1.3 Toppling of marble head-cross in Lixouri cemetery taken on 2/9/14 by NTUA
team. [GPS coordinates: 38.255833, 20.421111]
9-4
9.1.4 Displacement and rotation of a marble vase, responding as a rigid body at
Livadi cemetery taken on 2/8/14 by NTUA team. [GPS coordinates:
38.255555, 20.421111]
9-5
9.1.5 (a) A case of “double-rotation” in the Livadi cemetery: first rotates the massive
headstone structure and then the marble vase. (b) Sketch of the dimensions and
displacements of the slender marble artifact. [GPS coordinates: 38.255833,
20.421111; NTUA team, 2/8/14]
9-6
9.1.6 Rotation of a massive headstone in Chavriata. [GPS coordinates: 38.183219,
20.389813]. Photo taken by NTUA on 2/10/14.
9-7
9.1.7 Detailed views of the previous photo taken on 2/10/14 by NTUA team. [GPS
coordinates: 38.183219, 20.389813]
9-8
9.1.8 Sketch of the dimensions and displacement of rotated headstone.
9-9
9.1.9 Double rotation of the headstone and its base in opposite directions. The photo
on the left is a plan view of the rotation at the base. Lixouri cemetery, dated
2/9/14. [GPS coordinates: 38.192561, 20.438797]
9-10
9.1.10 Detailed views of the rotational movement located at three different interfaces
(shown with red rectangles and arrows). Rotations occurred in opposite
directions. Lixouri photo taken on 2/9/14 by NTUA team. [GPS coordinates:
38.192780, 20.438486]
9-11
9.1.11 Detailed views of the rotated lower marble pedestal and toppling of the slender
cross headstone. Lixouri cemetery, photo taken on 2/9/14 by NTUA team.
[GPS coordinates: 38.192436, 20.438666]
9-12
9.1.12 Toppled headstone (top) and horizontal slippage of tomb panel (bottom).
Chavriata cemetery photo taken on 2/11/14 by NTUA team. [GPS coordinates:
38.183013, 20.389619]
9-13
9.1.13 Rotation of several grave ledgers at the same direction in Livadi. [GPS
coordinates: 38.255833, 20.421111]. Photo taken on 2/8/14 by NTUA team.
9-13
9.1.14 Cracked marble panels, toppled artifacts and overturning headstones in
Kourouklata. [GPS coordinates: 38.242500, 20.474166]. Photo taken on 2/8/14
by NTUA team.
9-14
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9.2.1 Reconnaissance of 27 cemeteries in Cephalonia. Colored dots indicate
percentage of toppled tomb objects: red for more than 65%, yellow 30-65%,
and green less than 30%.
9-15
9.2.2 Vouni village cemetery [GPS: 38.178456, 20.404778] toppled objects
following the: (a) 1st event (taken on 1/28/14) and (b) 2
nd event (taken on
2/20/14). Photos by ITSAK and DUTH teams.
9-16
9.2.3 Objects toppled mainly towards the East: (a) Atheras [38.311280, 20.418498]
and (b) Kontogennada East [GPS: 38.250936, 20.396137]. Photos by AUTH
team on 2/11/14.
9-16
9.2.4 Cases of tomb objects toppling to the West: (a) Vouni [GPS: 38.178455,
20.404778] and (b) Atheras [GPS: 38.311280,2 0.418498]. Photo by DUTH
and AUTH teams on 2/11/14.
9-17
9.2.5 Rotation of a massive headstone, responding as a rigid body without toppling,
toppling, at the Chavriata cemetery [GPS: 38.183219, 20.389813]. Photo by
NTUA team on 2/10/14.
9-18
9.2.6 Headstone rotation without toppling at the south cemetery of Kourouklata
[GPS: 38.242361, 20.474188]. Photos by NTUA team on 2/8/14.
9-19
9.2.7 Livadi cemetery [GPS: 38.255689, 20.421035] after the 2nd
event: (a)
Displacement and rotation of two neighboring low rise marble block
constructions (A and B) and (b) Detail of displacement and rotation of marble
block construction B. Photos taken by UTH team on 2/8/14.
9-19
9.2.8 In (a) Skineas [GPS: 38.240479, 20.395151] a mere 7% of objects toppled; in
0.8 km east at (b) Vlichata [GPS: 38.238268, 20.403932] 71% of objects
toppled. AUTH team photos on 2/11/14.
9-20
9.2.9 View of total destruction view at Chavriata cemetery [GPS: 38.183013,
20.389619]: broken marble panels, toppled artifacts, overturned headstones.
Photos by NTUA team on 2/10/14.
9-20
9.2.10 Two Kourouklata cemeteries [GPS: 38.243401, 20.474875] where: (a) 59%
(north) and (b) 76% (south) of objects toppled. Photos by UPATRAS team on
(a) 2/11/14 and (b) 2/8/14.
9-21
9.2.11 Cemetery reconnaissance at North Paliki peninsula. Red dots indicate object
toppling rate greater than 65%, yellow from 30-65% and green with less than
30%. Observations indicated that adjacent cemeteries could exhibit markedly
different response.
9-22
9.2.12 Two marble statues standing opposite to each other at the entrance of Lixouri
City Hall (38°12'3.53"N, 20°26'14.92"E). Overturned statue south of entrance
recorded by UTH after 2nd
event; (b) Displaced but still standing statue north of
entrance after 1st event (ITSAK photo, 1/28/14); Top of statue toppled after the
2nd
event (Photo by ITSAK – AUTH-LSDGEE teams on 2/11/14).
9-23
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Chapter 9 Page
9.2.13 Marble statue close to Argostoli Customs building (38°10'47.94"N,
20°29'22.47"E): Slight base rotation. Photo by ITSAK – AUTH-LSDGEE
teams on 2/11/14.
9-24
9.2.14 Monument of Ilias Antipas mainly rotated (38.18305° N, 20.50030°E). The
rectangular sketch shows rotated part at its base (in cm). Photo by UPATRAS
teams on 2/8/14.
9-24
9.2.15 Marble monument near Lixouri (38°13'32.85''N, 20°25'46.42''E): Lateral
displacement without significant rotation (dimensions in cm). Photo by
UPATRAS team on 2/8/14.
9-25
9.2.16 Marble monument at Lixouri (38°11'51.7''N, 20°26'17.3''E). Dislocation and
toppling of upper two marble blocks towards S-SW direction. Photo by
LSDGEE-AUTH team on 2/11/14.
9-25
9.2.17 Overturning of massive Corinthian-type capital carrying a heavy top slab in
Lixouri. [GPS coordinates: 38.192713, 20.43]. Photo taken by NTUA team on
2/9/14.
9-26
9.2.18 The house across the street of the Public Library of Lixouri. No damage is
noticed, but a statue overturned (marked with turquoise circle). Photo by
NTUA team on 2/10/14.
9-27
9.2.19 Toppling and rotation of rigid block at a shoreline road house next to Lixouri
National Bank [38o12'9''N, 20
o 26'19.8''E]. Measurements by Diatonos
Mechaniki; MRCE photos, 2/10/14.
9-28
9.3.1 Correlation of damage in all cemeteries inspected to the shortest distance from
the (hypothetical) trace on the surface of the seismogenic fault of the 2nd
event.
Insert: geologic ΙΓΜΕ map showing in blue the preliminary reference line
used to calculate the distance to the cemeteries.
9-30
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Figure
Chapter 10 Page
10.1.1 EYDAP vehicles arriving from the central facilities in Athens to Cephalonia
via ferry boat, with the investigation and repair teams members who were
joined by local colleagues.
10-2
10.1.2 Digital Elevation Model (EYDAP, 2014).
10-4
10.1.3 Topographic map showing Lixouri water networks (EYDAP, 2014).
10-4
10.1.4 GIS mapping of a total of 36,191 m of potable water network pipes (EYDAP,
2014).
10-5
10.1.5 Rapid network assessment at the end of the first day (EYDAP, 2014).
10-5
10.1.6 Examples of the numerous repair of leaks repaired (EYDAP, 2014).
10-7
10.1.7 Nineteen new valves were installed by EYDAP shown with red dots.
10-8
10.1.8 Progress made at the end of the first day.
10-8
10.1.9 EYDAP Personnel repairing leaks during Day 2 (EYDAP, 2014).
10-9
10.1.10 EYDAP Personnel repairing leaks Days 3 to 12.
10-10
10.1.11 Potable water network fully functioning at the end of repair activities.
10-10
10.1.12 EYDAP wastewater network mission field personnel arrived on 2/7/14 and
worked at the island for six days. Photos by: (a) EYDAP; and (b)
GEER/EERI/ATC reconnaissance team.
10-12
10.1.13 EYDAP equipment and field personnel for wastewater network.
10-13
10.1.14 EYDAP equipment and field wastewater network personnel.
10-14
10.1.15 Video inspection shots (EYDAP, 2014).
10-15
10.2.1 Main Cephalonia road network (modified from inagiaefimia.com).
10-16
10.2.2 Settlement of western embankment of Havdata bridge, recorded by
reconnaissance team members S. Nikolaou and M. Moretti (38°12'10.30"N,
20°24'16.05"E).
10-17
10.2.3 North of Soularoi road embankment sliding, as viewed from the pavement
(38°11'21.51"N, 20°24'45.80"E).
10-18
10.2.4 Masonry wall collapse in NS direction of Kardakata road embankments after
the 2nd
event (38°17'34.61"N, 20°27'8.16"E)
10-18
10.2.5 Rockfalls in Aghia Thekla village road (38.25°N, 20.3833°E, from
inkefalonia.gr).
10-19
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Chapter 10 Page
10.2.6 Rockfalls at main asphalt road connecting Lixouri to Argostoli. Web photo
from madata.gr after the 1st event.
10-19
10.2.7 Collapse of masonry wall at courtyard of The Virgin Mary church at Chavriata
causing local traffic disruption (38°10'57.32"N, 20°23'14.48"E).
10-20
10.2.8 Traffic disruption due to nonstructural elements damage in Krasopatera Street,
Lixouri (38°11'36.81"N, 20°26'11.42"E).
10-20
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Figure
Chapter 11 Page
11.1.1 Areas visited by the reconnaissance teams where most of structural damage
occurred.
11-1
11.1.2 A two-story RC building in Livadi which performed well, despite the fact that
at this area where several buildings suffered significant damage. Evidence of
high accelerations if the dislocation of roof tiles observed in several structures
throughout the meioseismal area.
11-2
11.1.3 Damage of 2-story RC building in Aghios Dimitrios designed with older codes
(GPS coordinates: 38.229444, 20.429722): (a,b) after 1st and 2nd events; (c,d)
beam-column detail of (b).
11-3
11.1.4 Significant damage to the soft story columns of a two-story RC building in
Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E). No damage was observed
at the upper floor.
11- 4
11.1.5 Collapse of the masonry ground floor of a two-story building in Aghios
Dimitrios. The upper floor is a reinforced concrete frame, added several years
after initial construction (GPS coordinates: 38.229444, 20.429722).
11-4
11.1.6 Partial collapse of a heritage masonry building in Samoli, close to Livadi
village (see Fig. 11.1.1), which was probably built during the 17th century. The
building had survived the 1953 earthquakes with some damage which had
subsequently been repaired.
11-5
11.1.7 Severe damage of brick infill walls of a two-story RC building in Livadi (Fig.
11.1.1). The frame suffered only minor damage (38°13'48.19"N,
20°25'53.20"E).
11-5
11.1.8 Examples of nonstructural architectural components failure: (a) overturning of
a masonry fence in Lixouri; (b) collapse of a pergola in Livadi.
11-6
11.3.1 Typical degrees of damage in vertical structural elements of Reinforced
Concrete (RC) structures according to YAS (modified from (YAS, 2014).
11-8
11.3.2 Results of Rapid Assessment and Detailed Assessment phases. In the Rapid
Assessment, 31% or 1505 buildings were found unsafe to occupy. The Detailed
Assessment of the yellow-tagged buildings found 46% (1265) safe, 48%
(1325) temporarily unsafe, and 6% (180) unsafe and pending detailed
evaluation of whether to repair or demolish.
11-9
11.3.3 Detailed assessment of 2,770 buildings: 1,167 were RC (60, 39, 1% tagged
green, yellow, red); 765 were masonry (29, 54, 17% tagged green, yellow,
red); 783 were hybrid (40, 56, 4% tagged green, yellow, red); and 85 were
other (48, 41, 11% tagged green, yellow, red).
11-10
11.3.4 Types of the 180 red-tagged buildings of the Detailed Assessment: 5%
reinforced concrete, 73% masonry, 17% hybrid concrete-masonry, and 5%
other types.
11-10
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Figure
Chapter 11 Page
11.4.1 Typical single story masonry building constructed after the 1953 earthquake.
11-12
11.4.2 Smooth steel bars of a vertical Reinforced Concrete (RC) tie, typical for RC
building construction during the 1950's and 1960's.
11-13
11.4.3 (a) Collapse of 1st story of a masonry Arogi building where a 2nd story was
added more than two decades after the original construction. (b) Cement block
masonry reinforced with vertical and horizontal RC ties (GPS coordinates
38o13'49.80''N, 20o25'49.80''E.)
11-13
11.4.4 Typical bi-diagonal (shear) cracks in a masonry wall.
11-14
11.4.5 Shear failure of bearing walls and out-of-plane failure (corner of building and
top of walls) of a single-story stone masonry building. Note the double-leaf
construction of bearing walls and local disintegration of the outer leaf.
11-14
11.4.6 Typical three-leaf stone masonry construction. Damage includes separation of
leaves, probably present before the earthquakes, and partial collapse of the wall
due to out-of-plane bending.
11-15
11.4.7 Structural damage of the Virgin Mary masonry church in Chavriata
(38°10'57.52"N, 20°23'13.61"E) after the 2nd event, affected by the stone
masonry retaining wall collapse (Section 8.3).
11-15
11.4.8 Observed cracks possibly due to church displacement towards the failed
retaining wall. (a) Seismic retrofit RC jacket below window; (b) absence of
jackets (38°10'57.52"N, 20°23'13.61"E).
11-16
11.4.9 Typical shear and out-of-plane damage in the northeast corner of the stone
masonry church of Aghia Thekla (38°14′41″N 20°23′06″E).
11-16
11.4.10 Collapse of intermediate story of 3-story RC building completed in 2007. (GPS
coordinates: 38.258888, 20.424444).
11-18
11.4.11 Building of Fig. 11.4.10 (GPS coordinates: 38.258888, 20.424444): (a) damage
of RC bearing elements on ground floor; (b) indication of different ground
motion in main building directions.
11-18
11.4.12 Poor behavior of infill walls with disintegration of vertically perforated bricks
observed at the building of Fig. 11.4.10 (GPS coordinates: 38.258888,
20.424444).
11-19
11.4.13 Two-story building that experienced typical soft story damage in Aghios
Dimitrios (38o14'36.51''N, 20
o25'41.91''E).
11-19
11.4.14 Crushing of concrete and fracture of closely spaced, single rectangular hoops
of the columns of the two-story building in Fig. 11.4.13 (38o14'36.51''N,
20o25'41.91''E).
11-20
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Figure
Chapter 11 Page
11.4.15 Damage of 2-story RC building in Aghios Dimitrios (38°13′45.6″N
20°25′47.4″E): (a) shear cracks and separation of infills after 1st event; (b)
failure of columns and joints after 2nd event; (c, d) detailing with single
rectangular largely spaced hoops; and (e) detail of beam-column joint failure.
11-20
11.4.16 Residential 1962 "Arogi" public housing complex in Lixouri (GPS coordinates
20.434256, 38.21159) with: (a) extensive damage of infill walls and structural
elements; (b) failure of a column. Note large spacing of single rectangular
hoops.
11-21
11.4.17 Single story building in the public housing complex of Fig. 11.4.16 without
earthquake resisting frames: (a) damage to the columns; (b) detail of slab-
column joint.
11-21
11.4.18 (a) Two-story residential buildings of 1978 with severe damage on the ground
floor and minor damage on the upper floor; (b, c): Details of damage
(coordinates 38.211567, 20.434134).
11-22
11.4.19 (a) Failure of upper part of the RC belfry of Aghios Ioannis church in
Kourouklata (GPS coordinates: 38.242119, 20.473977); (b) detail showing
poor detailing of rather short columns with stiff upper part, flexible lower part.
Failure and crushing of concrete.
11-22
11.4.20 Typical infill wall construction from the 1960’s that incorporates reinforcement
with vertical and horizontal rebars that have likely contributed to satisfactory
performance of many buildings of that time. This photo shows a building in
Lixouri during rehabilitation.
11-23
11.4.21 Two-story timber residential structures in Aghios Dimitrios. The only damage
observed was a crack at the interface of the wood frame/walls with the concrete
base slab.
11-23
11.5.1 Current seismic zoning of Greece (EAK, 2000) for ground type A (rock) with
zones I, II, III of reference ground acceleration ag of 0.16, 0.24, and 0.36 g.
Cephalonia is in Zone III.
11-25
11.5.2 Cephalonia elastic acceleration response spectra for various ground types based
on Eurocode EC-8 and the Greek seismic code EAK-2000.
11-26
11.5.3 Comparison of elastic response spectra for various ground types, based on
current seismic codes (EC-8 and EAK-2000) with spectra of recorded motions
from the 1st event of 1/26/14.
11-27
11.5.4 Comparison of elastic response spectra for various ground types, based on
current seismic codes (EC-8 and EAK-2000) with spectra of recorded motions
from the 2nd event of 2/3/14.
11-27
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Chapter 11 Page
11.5.5 Typical pre-1953 masonry buildings in Cephalonia.
11-29
11.5.6 Pre-1953 masonry construction: (a) partial collapse of a Chavriata house
(38o11'0.67''N, 20
o22'54.93''E), 50 m from station CHV1; (b) collapse of
building Chavriata; (c) collapse of 2-story house in Havdata (38o12'11.62''N,
20o23'09.01''E); (d,e) partial collapse of secondary-use buildings; and (f,g)
adjacent buildings with no damage in (g) that had reinforced concrete ties at
the top.
11-30
11.5.7 Arogi-type buildings post-1953: (a) typical Arogi house in Livadi; (b)
Chavriata old school (38o11'00.67''N, 20
o22'54.93''E) with cinder block
construction with recording station CHV1; (c) details of encased reinforced
cinder walls with cement based mortar.
11-31
11.5.8 (a) Locations of CHV1 accelerometer in Chavriata old school building
(38o11'00.67''N, 20
o22'54.93''E) and four buildings within 45 to 52 meters
around it; (b) three buildings east of CHV1: partially collapsed stone house,
Arogi house, and two-story RC building.
11-32
11.5.9 Exterior (top) and interior (bottom) damage of the old school building in
Chavriata (38o11'00.67''N, 20
o22'54.93''E) where the CHV1 accelerometer is
located.
11-34
11.5.10 Two-story reinforced concrete frame building next to the old school in
Chavriata 45 m from the CHV1 accelerometer (38o11'0.67''N, 20
o22'54.93''E)
that experienced no structural damage.
11-33
11.5.11 Three-story building in Lixouri (with partial 4-story extensions) probably
constructed before 1984 following the 1959 code (38o12'14.17''N,
20o26'01.45''E). Collapse of some infill walls on 3rd and 4th floors
(incomplete, no door/window frames) and cracks at column-beam joints on 4th
floor.
11-34
11.5.12 Three-story building in Lixouri (Aravantinou Krasopatera St., 38o11'36.81''N,
20o26'11.42''E), probably built before 1984. The two upper floors did not
appear to suffer any structural or infill wall damage. The columns and shear
walls (or wide columns) of the 1st floor were severely damaged (soft-story
failure).The structure was later demolished.
11-34
11.5.13 (a) Three-story hotel building in Argostoli (38o10'80.00''N, 20
o29'14.40''E)
designed in 1989 using the supplementary provisions to the 1959 building
code; (b) width of the construction join opening; (c) broadening of joint after
the 2nd event.
11-35
11.5.14 Two-story RC frame with infills in 2nd story in Aghios Dimitrios
(38o14'36.51''N, 20
o25'41.91''E). The building plan is rectangular with one side
twice as long as the other.
11-36
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Figure
Chapter 11 Page
11.5.15 Typical buildings in the city of Lixouri designed according to the current
seismic code EAK-2000 had no visible damage.
11-37
11.5.16 Two-story house in Livadi (38o15'24.81''N, 20
o25'31.77''E), east of the Lixouri-
Argostoli road. (a) infill wall cracking from the exterior; (b) infill wall failures
from the interior.
11-37
11.6.1 Two-story house in Livadi (38o15'26.13''N, 20
o25'21.38''E). Damage is evident
in every column of the 2nd floor and in some infill panels. No damage to the
1st floor was visible from the exterior.
11-38
11.6.2 Top: sketch of the building plan view in Aghios Dimitrios (38o14'36.51''N,
20o25'41.91''E) and pictures showing the structure and its connection to the
foundation. Bottom: sketch of the building elevation. Colors indicate the three
phases of the construction.
11-40
11.6.3 Tilted 2-story building in Aghios Dimitrios (Arogi house on 1st floor and 1978
RC clay-brick infill frame on 2nd floor). Failed columns and walls of the 1st
story showed few stirrups along the columns and only 4 longitudinal
reinforcing bars in the cross section (38o13'50.45''N, 20
o25'49.78''E).
11-41
11.6.4 Public low income housing complex. Top: severe damage of the three story
buildings built in 1962. Top right: lack of shear reinforcement. Center: public
housing blocks/units. Buildings with red roof on the lower portion are
undamaged two-story houses built after 2000 with the current seismic code.
Bottom: Repairable damage at two-story buildings built in 1978.
11-42
11.6.5 Typical drawings collected for the 2-story RC building shown on Fig. 11.5.7,
about 50 m from CHV1 accelerometer in Chavriata (38o11'00.67''N,
20o22'54.93''E). Construction was done in two phases, in 1978 with an addition
in 2000. The building suffered no visual structural damage.
11-43
11.6.6 The administration Lixouri building (left) and photos of instrumentation with
special accelerometer array (right).
11-44
11.6.7 Instrumentation layout of Administration building at Lixouri.
11-45
11.7.1 Cephalonia International Airport terminal building (ID #14, coordinates
38°7'10.0''N, 20°30'17.7''E): (a) aerial photo; (b) nonstructural damage after the
2014 events resulted in closing the terminal for three weeks.
11-47
11.7.2 Lixouri Town Hall. (ID#3 in Table 11.7.1; coordinates 38°12'3.53"N,
20°26'14.92"E). (a) before the 2014 events; and after the 2nd event: (b) column
damage; (c) overturning of statue.
11-47
11.7.3 Open construction joint at Argostoli Port Authority (ID#8 in Table 11.7.1;
coordinates 38o10'44.8''N, 20
o29'23.3''E).
11-48
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Figure
Chapter 11 Page
11.7.4 (a) Merchant Naval Academy building (ID#10 in Table 11.7.1) in Argostoli
(coordinates 38°11'4"N, 20°29'9"E; photo from kefalonia.net.gr); (b)
Observation following the 2nd event of lack of shear reinforcement and
corrosion of rebars.
11-48
11.7.5 Argostoli Archeological Museum (ID#11 in Table 11.7.1; coordinates
38°10′40″N 20°29′17″E). (a) photo taken after the 2000 rehabilitation but
before the 2014 events (mygreece.travel); (b) concrete spalling; and (c) minor
cracking at short columns. Both photos taken after 2nd event.
11-49
11.7.6 Lixouri “Mantzavinateio” General Hospital (ID #1, 38o10'44.8''N,
20o29'23.3''E): (a) historic photo of structural frame completion prior to 1953;
(b,c) structural and geotechnical investigations for 2004-12 seismic retrofit; (d)
evacuation after 1st event (inkefalonia.gr, 2014). Following assessment, the
hospital was deemed safe and operations resumed few days after the 2nd event.
Retrofit and historic information and photos a,b,c from Barthakis (2014).
11-50
11.7.7 Examples of satisfactory behavior of Argostoli administrative public buildings:
(a) Prefecture building (ID #13); and (b, c) Court House (ID #4, coordinates
38°10'37"N, 20°29'18"E).
11-50
11.7.8 “Petritsio” high school, Lixouri (School ID#1, 38°12'12.87"N, 20°26'15.43"E):
(a) prior to 2014; after 2nd event: (b) concrete spalling at external beam; (c)
beam-column joint failure.
11-51
11.8.1 Façade of typical Greek Orthodox Basilica church.
11-52
11.8.2 Typical church nave and iconostasis.
11-52
11.8.3 Church locations inspected during reconnaissance efforts (top) with details in
the western part of the Paliki peninsula (bottom).
11-53
11.8.4 Freestanding Tower belfry in Chavriata (38o10'57.47''N, 20
o23'14.4''E).
11-54
11.8.5 Belfry incorporated into walls.
11-54
11.8.6 Collapse of masonry retaining wall at courtyard of The Virgin Mary church at
Chavriata (ID#1 38o10'57.47''N, 20
o23'14.4''E): (a) condition before the 2014
events; (b) damage after 1st event; (c) collapse after 2nd event.
11-55
11.8.7 Typical damage of stone gables in the churches of: (a, b) The Virgin Mary of
Rongoi (ID#9) – (a) shows original condition prior to the 1953 earthquakes; (b)
The Virgin Mary at Kechrionas (ID#6); and (c) Aghios Ioannis Theologos at
Kontogenada (ID#24).
11-57
11.8.8 Collapse of stone gable due to loss of continuity between stone wall and gable
through installation of a RC lintel in the churches: (a) Aghios Nikolaos at
Aghia Thekli (ID#11); (b) Aghios Vlasios (Blaise) at Dematora (ID#11).
11-58
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11.8.9 Typical damage to Category 4 (strengthened masonry) churches to the top part
of the walls due to inadequate overlap of the lintel reinforcment.
11-58
11.8.10 Typical damage in Category 5 churches: Collapse of the outer stone leaf of the
west gable, at a church strengthened with internal RC wall.
11-58
11.8.11 Typical damage to Category 4 churches at top part of the walls of a
strengthened masonry church due to inadequate overlap of the lintel
reinforcment.
11-59
11.8.12 Damage in Category 7 church: Permanent out of plane displacement of
approximately 7 cm at the top of the walls along the long sides of the structure.
11-59
11.8.13 (a) Collapse of RC belfry top due to column failure (38o14'32.25''N,
20o28'26.40''E); (b) Detail of deformed rebars.
11-59
11.8.14 Category 1 Church of Aghia Marina at Soulari (ID#43): (a) before the
earthquakes (b) Collapse of bell tower (c) Partial collapse of the east stone
gamble.
11-60
11.8.15 Category 6 church experienced moderate damage of the RC frame infills. The
roof tiles located at center of the building were displaced but the ones closer to
the edges remained intact.
11-60
11.8.16 Severe nonstructural damage was observed in many churches: (a) fallen objects
and out of plain deformation of iconostasis; (b) damage due to falling stones.
11-61
11.9.1 Base anchorage failure at heavy stair railings in Lixouri.
11-65
11.9.2 Heavy, unbraced storage units with the potential to block means of egress in
the National Bank branch of Lixouri. (GPS coordinates: 38°10'27.3''N,
20°29'26.4''E).
11-65
11.9.3 Freestanding fences without foundations or reinforcement were damaged.
(GPS coordinates: (a) 38°11'0.8''N, 20°22'53.9''E, (b) 38°12'41.0''N,
20°26'1.4''E).
11-66
11.9.4 Glazing failure due to lack of proper design for lateral frame deformation.
11-66
11.9.5 Mitigation method for bracing interior partitions as recommended (FEMA, E-
74).
11-67
11.9.6 Lack of support for ceiling tiles and recessed light fixtures in the ground level
of the National Bank branch of Lixouri. (GPS coordinates: 38°10'27.3''N,
20°29'26.4''E).
11-67
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11.9.7 Poorly anchored sidewalk lighting columns in: (a) Lixouri port (Easy Facilities
team members George Tsalakias and Angeliki Psychogiou in the photo) and
(b) Argostoli (GPS coordinates: (a) 38°12'7.2''N, 20°26'18.2''E; (b)
38°12'1.0''N, 20°26'18.2''E).
11-68
11.9.8 Ceiling brace buckling in the Eurobank branch of Argostoli: (a) horizontal strut
and (b) vertical brace. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
11-69
11.9.9 Mitigation option to provide diagonal bracing for ceiling systems in FEMA E-
74.
11-69
11.9.10 Roof tiles damage (GPS coordinates: (a) 38°13'46.2''N, 20°25'48.0''E; (b)
38°13'45.6''N, 20°25'48.7''E).
11-70
11.9.11 Collapse of tiled roof in Livadi (38°15'29.19''N, 20°25'26.72''E). Photo by V.
Plevris of ASPETE team.
11-70
11.9.12 Typical parapet gable frame failures in Lixouri.
11-71
11.9.13 Architectural marble veneer damage due to building pounding.
11-72
11.9.14 Improperly anchored gutter pipes with rigid connections. (GPS coordinates: (a)
38°12'7.2''N, 20°26'19.8''E; (b) 38°11'0.1''N, 20°22'55.9''E).
11-73
11.9.15 Dislocated drain pipe at the perimeter of a 2-story R/C building located near
the shore south of Lixouri. (GPS coordinates: 38°11'36.08''N, 20°26'19.90''E).
11-74
11.9.16 Rooftop AC unit that fell off brick supports (GPS coordinates: 38°10'27.0''N,
20°29'26.5''E).
11-74
11.9.17 Mechanical external AC equipment with adequate bracing that suffered no
damage in Argostoli.
11-75
11.9.18 Well-braced cable trays in second floor mechanical space in the Eurobank
branch of Argostoli. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
11-75
11.9.19 Differential settlement in power transformer pillar (GPS coordinates:
38°11'55.63''N, 20°26'20.56''E). See also SSI Section of Chapter 8.
11-76
11.9.20 Desktop computers and accessories without anchorage or support. Team
member Ramon Gilsanz of GMS in the photo (GPS coordinates: 38°12'8.4''N,
20°26'17.4''E).
11-77
11.9.21 Rotational movement of a heavy bank teller desk with no anchorage (GPS
coordinates: 38°12'6.6''N, 20°26'17.4''N).
11-77
11.9.22 Overturned statues at the entrance of Lixouri City Hall. (GPS coordinates:
38°12'3.53''N, 20°26'14.92''E).
11-78
GEER/EERI/ATC Cephalonia, Greece 2014 List of Figures Report Version 1 xliii
Figure
Chapter 11 Page
11.9.23 Sliding and rotation of a heavy bank vault with no anchorage on the floor or
ceiling. (GPS coordinates: 38°12'7.8''N, 20°26'19.2''E).
11-79
11.9.24 Rotational movement of heavy bank vault at the Eurobank branch of Argostoli.
(GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
11-79
11.9.25 Measurements taken (by Dimitri Kopanos of Easy Facilities team) at a row of
heavy vaults at the Eurobank branch of Argostoli show approximately 2.5 cm
of displacement. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
11-80
11.9.26 Bookcases braced to one another for support but lacked shelving restraints.
(GPS coordinates: 38°10’27.3”N, 20°29’26.4”E).
11-81
11.9.27 File cabinet with no anchorage (GPS coordinates: 38°12'7.8''N, 20°26'19.2''E).
11-82
11.9.28 National Bank branch of Lixouri located in the front row of buildings parallel
to the shoreline (GPS coordinates: 38°12'7.8''N, 20°26'19.8''E). See also
Chapter 9 for this case study.
11-82
11.9.29 Corner hooks installed after the 1st event at top of large storage units and
bookcases at the National Bank branch of Lixouri prevented movements in the
2nd event. (GPS coordinates: 38°12'7.2''N, 20°26'19.8''E).
11-83
11.9.30 Simple rod restraints installed by a restaurant owner (shown here with team
members) at Havdata village prevented toppling of bottles. (GPS coordinates:
38°12'14.3''N, 20°23'12.0''E).
11-83
11.9.31 Shelving with simple string restraints at a gas station and supermarket in
Lixouri.
11-84
11.9.32 Lack of seismic protection for rolling restaurant shelves and refrigerator units
in Lixouri.
11-84
11.9.33 Cephalonia International Airport (38°7'10.0''N, 20°30'17.7''E).
11-85
11.9.34 Interior conditions of the airport. (GPS coordinates: 38°7'10.0''N,
20°30'17.7''E).
11-86
11.9.35 Exterior of the airport, no significant structural damage was recorded. (GPS
coordinates: 38°7’10.0”N, 20°30’17.7”E)
11-86
GEER/EERI/ATC Cephalonia, Greece 2014 List of Figures Report Version 1 xliv
Figure
Chapter 12 Page
12.1 Results of detailed assessment of 2,770 buildings (see Chapter 11 for details).
12-1
12.2 Temporary housing options included a cruise ship (photo by reconnaissance
teams).
12-4
12.3 Temporary housing options of tents (left AP, N. Stamenis, vcstar.com) or
public facilities and churches for the elderly (right, from the web).
12-4
12.4 Assistance by the Greek Red Cross immediately after the events. Photos from
Patras volunteers of the Red Cross and Good Samaritans (Σώμα Εθελοντών,
Σαμαρειτών, Διασωστών και Ναυαγοσωστών). (Photos frompatrasevents.gr)
12-5
12.5 Distribution of bottled water to Lixouri residents following the 2nd event
(photo by reconnaissance teams).
12-5
12.6. Fundraising efforts in Athens and Sydney, Australia.
12-6
12.7. The bottle of water from the Aegean sea that was emptied at Lixouri in the
Ionian sea to symbolize their connection and mutual support in the aftermath of
the Cephalonia earthquakes of 2014. Artwork by archaeologist Maria Rota,
photo from inkefalonia.gr.
12-7
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List of Tables
Table
Chapter 2 Page
2.2.1 Cephalonia focus towns of the GEER/EERI/ATC reconnaissance and their
coordinates.
2-8
Note: No tables are included in Chapters 1, 3, 4, 6, 12 and 13.
GEER/EERI/ATC Cephalonia, Greece 2014 List of Tables Report Version 1 xlvi
Table
Chapter 5 Page
5.1.1 Information on source parameters of strong (M≥6.0) earthquakes in the area of
Cephalonia from 1469 to 1983 (Papazachos and Papazachou, 2003).
5-4
5.1.2 Modified Mercalli (MM) intensities and corresponding effects.
5-5
5.1.3 Venetian documentary sources of information regarding the Ionian islands,
available from the State Archives of Venice (ASVe, 1712-1764). Modified
from Albini, et al. (1994).
5-7
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Table
Chapter 7 Page
7.1.1 Accelerographic stations and ground motion parameters within epicentral
distances of 200 km from 1st event (1/26/14, Mw6.1). Station location, code,
owner, geographical coordinates, epicentral and hypocentral distances, azimuth
and PGA (cm/s2) for N/L, E/T, Z/V components.
7-6
7.1.2 Highest PGA values and their components recorded during the 1st event at
stations ARG2, VSK1, LXRB, SMHA at epicentral distances of 13, 34, 10, 29
km, respectively.
7-8
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Table
Chapter 8 Page
8.1.1 Eurocode EC-8 and ASCE7-05 site classification. 8-13
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Table
Chapter 9 Page
9.3.1 Summary of statistics from cemeteries: Entries 1 through 17 are in Paliki
peninsula (west part of Cephalonia), ordered from North to South. Entries 18 to
26 are on the main (east) part of the island. Light red indicates toppling rate
over 65%; light yellow from 30-65%; and light green less than 30%.
Generalized geologic setting: A = Conglomerate, sandstone and limestone and
B = Conglomerate and brecciated limestone with marls.
9-31
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Table
Chapter 10 Page
10.1.1 Potable water pipe network material and length in the town of Lixouri. 10-5
GEER/EERI/ATC Cephalonia, Greece 2014 List of Tables Report Version 1 li
Table
Chapter 11 Page
11.5.1 Eurocode EC-8 and ASCE7-05 ground types and site classification.
11-26
11.7.1 Public reinforced concrete buildings visually inspected during reconnaissance.
11-46
11.7.2 Educational buildings visually inspected during reconnaissance and assessed
by Ο.Σ.Κ..
11-51
11.8.1 Cephalonia Orthodox Churches, including name, location, century of
construction and repair, Category of Load Bearing (LB) system and Degree of
Damage (DD) from the 2014 events.
11-56
11.9.1 Nonstructural components damage observations and construction or design
deficiencies by Category of components: architectural, building utilities,
furniture and contents.
11-64
CHAPTER 1
Introduction
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
1 Introduction Two major earthquakes with moment magnitudes of Mw = 6.0 and Mw = 6.1 hit the
Cephalonia Island of Greece on January 26th and February 3rd of 2014, respectively. Cephalonia
has a remarkable seismic history that can be traced back to antiquity. In 1953, the island was
destroyed by a sequence of destructive shocks that caused more than 450 deaths. No lives were
was lost during the 2014 earthquakes. The majority of the structures performed remarkably
well considering they were subjected to ground motions that were often more than twice their
elastic code design values probably due to significant site and topographic effects. However,
damage to nonstructural elements was significant enough to affect life, business operations,
and economy.
The reconnaissance mission of the Cephalonia earthquakes was unique for two main
reasons: First, it brought together the local, highly qualified earthquake engineering community
with the United States GEER/EERI/ATC group to form a multidisciplinary team of more than
70 people, who documented geotechnical, structural, and nonstructural observations. Second,
the resiliency of the building stock, geostructures, and communities that responded
successfully to one of the highest sequence of ground motions ever recorded in Europe
provided the opportunity to focus on collecting data of successful performance in addition to
failures − a new generation of reconnaissance.
The efforts after the Cephalonia earthquakes has yielded a number of invaluable datasets,
lessons, and suggestions for future research. This report presents reconnaissance team
observations on:
(i) seismological and recorded motions (ii) geotechnical aspects (iii) rigid blocks behavior (iv) structural response (v) infrastructure lifelines (vi) nonstructural components response (vii) economical and societal aspects.
Data collected, including instrumentation and design documentation, can be used in
combination with much needed in-situ geotechnical testing and 3-D mapping to further
understand the recorded ground motion. The information will also allow us to analyze and
explain the successful response of the built and natural environment.
GEER/EERI/ATC Cephalonia, Greece 2014 1 - Introduction Report Version 1 1-1
CHAPTER 2
Cephalonia Island and Areas
Covered
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐1
2.1 Cephalonia island Cephalonia is an island known for its natural beauty (Fig. 2.1.1), located in the Ionian Sea
of Greece, next to the island of Ithaca, where the kingdom of Odysseus was in the Homeric
poems of Odyssey and Iliad (Fig. 2.1.2). It is the sixth largest island in the country; the largest
of the Ionian islands with area of 786 m2 and population of 35,800 people according to the
2011 census.
Figure 2.1.1. Natural beauty of Cephalonia island (photo from web).
The capital of the prefecture of Cephalonia and Ithaca is Argostoli, home to 8,000 people.
The name is derived from the Greek words "argo" and "stolos", which mean "slow fleet", since
the port has been in operation since ships used oars to navigate. Lixouri is the second major
town on the island, and combined with Argostoli they account for almost two thirds of the
prefecture's population. The name originates from "lixis" and "ourion", which mean
"termination of helpful stern wind", since offshore of Lixouri the southern stern winds drop
due to the existence of tall mountains close by (keffyroots.com , 2014).
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐2
Figure 2.1.2. Maps showing Cephalonia island (a) in Europe and (b) in Greece (nationsonline.org); and (c) map of the island showing the capital Argostoli and the town of Lixouri (kefallonia.gov.gr).
(a)
(a)
Ionian sea
N
CEPHALONIA
ITHACA
Argostoli
Lixouri
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐3
The island was first inhabited
around 10,000 BC. Based on Greek
mythology, "Kefalos" (Fig. 2.1.3),
a refugee from Athens, came to
Cephalonia and conquered the
western peninsula of the island (the
southwest quadrant of present day
Paliki) and, over a period of time,
the entire island. King Kefalos had
four sons; Pali, Sami, Krani and Proni. He awarded his sons portions of the island, all of which
gradually became autonomous democracies with their names still on towns of present-day
Cephalonia. Kefallinia, as it was called by Herodotus, has also been suggested as the Homeric
Ithaca, home of Odysseus, as opposed to the smaller island named Ithaca today. Indeed, in the
Iliad Homer mentioned the Cephallenians as the people who lived there and the hypothesis of
both islands being connected as one state under Cephalonia is being explored. According to
another hypothesis, the island of Cephalonia was two different islands, with the Paliki
Peninsula being ancient Ithaca and the remaining of Cephalonia being ancient Same.
According to this hypothesis, the thin strip of sea separating the two islands is the channel that
geographer Strabo (64/63 BC – c. AD 2) described when he visited the area (Fig. 2.1.3), that
has been filled since with sediments, catastrophic rockfalls, co-seismic uplift events and
relative sea-level change (Underhill, J. 2009).
Figure 2.1.3. Image of King Kefalos from the Greek mythology (keffyroots.com, left). Map of the hypothesis that present-day Cephalonia was two islands and that the Paliki Peninsula was ancient Ithaca (odysseus-unbound.org). Names shown are hypothesized ancient names used by Homer (right).
I am Odysseus, Laertes' son, world-famed
For stratagems: my name has reached the heavens.
Bright Ithaca is my home: it has a mountain,
Leaf-quivering Neriton, far visible.
Around are many islands, close to each other,
Doulichion and Same and wooded Zacynthos.
Ithaca itself lies low, furthest to sea
Towards dusk; the rest, apart, face dawn and sun.
Odyssey 9.19-26
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Figure 2.1.4. Old Argostoli port sketch from book of travels by Andre Grasset de Saint-Sauveur (1800).
Being at the cross roads of the Western and the Eastern worlds (Fig. 2.1.2), Cephalonia has
experienced occupations by a number of different rulers. The island still exhibits traces of all
the cultures that have been present on the island throughout its history that is expressed in the
rich literature and music local history. From 1082 until 1479 AD (13 years before Columbus
discovered America), the Normans dominated Cephalonia, followed by Turkish occupation in
1479 AD. In 1500 AD, twenty one years later, the Venetians captured St. George’s castle, 7
km from Argostoli (Fig. 2.1.5), and ruled for the next 300 years. During this period, the cities
of Argostoli and Lixouri began to grow. In 1757 AD, the Venetian Governor’s House was
moved from St. George’s castle to Argostoli, thus elevating it to capital of Cephalonia.
Figure 2.1.5. St. George’s castle from 12th century A.C., standing today near Argostoli (web photo).
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐5
In 1797 Napoleon abolished the Venetian State and the French, Russians, Turks and
English ruled the Ionian islands over the next 18 years. In 1850 AD the first Greek Parliament,
named the Ionian Parliament, was formed based on free elections. For the next 14 years the
Cephalonians struggled to unite with unoccupied Greece (parts of which were still under
Turkish occupation), which they achieved in 1864 AD. During World War II, the island was
occupied by both Italians and Germans and immediately after, a Civil War broke out in Greece.
Just a few years later, the earthquakes of 1953 AD hit the island, took hundreds of lives, and
destroyed most of the homes.
The Ionian Islands, as described in Chapters 5 to 7 of this report, are located in one of the
most tectonically active places in the world. Ten km west of Cephalonia the seabed drops from
a depth of 300 m to 3 km. Consistently, every few decades there is a major earthquake in the
area and big parts of the shoreline have been reclaimed using debris from the earthquakes.
During the 2014 seismic events, liquefaction phenomena were mainly triggered in waterfront
areas of Argostoli and Lixouri that reclaimed the sea following the destructive 1953 earthquake
sequence and essentially destroyed most of the island’s buildings. The urban area of Argostoli
before the 1953 destruction was virtually reconstructed by Pavlidis et al. (2010), shown on Fig.
2.1.6 with the antithesis after the destruction in Fig. 2.1.7 (with social welfare stamps as insert).
More details on historic earthquakes are provided in Chapter 5.
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐6
Figure 2.1.6. Argostoli before the 1953 earthquakes (from virtual walkthrough, Pavlidis et al., 2010).
Figure 2.1.7 Argostoli after the 1953 earthquakes (53vorini-gr). Social welfare stamps issued by Greece after the1953 earthquakes are shown on the bottom right insert (catawiki.com).
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐7
In recent years, construction and tourism are on the rise, and Cephalonia is one of the most
visited islands in Greece that includes an international airport. The famous bays of Myrtos (Fig.
2.1.8), Athera (north), Lourdata (south) attract many visitors that enjoy the unique combination
of roman, venetian and byzantine ruins, side by side with beautiful beaches.
Figure 2.1.8. Myrtos bay beach.
The island’s interesting morphology is known for its lakes and caves. Fig. 2.1.9a shows the
Drogarati cave, a large stalagmitic cavern of rare beauty and Fig. 2.1.9b shows the nearby semi-
underground lake of Melissani, with the characteristic deep blue waters. Local traditions
include wine production and culinary specialties. The island has rich biodiversity with few sites
listed in the EU Natura 2000 network. Sightseeing includes museums (Archaeological, Naval
and Environmental, Natural History, Ecclesiastical) and many notable churches dating back to
the renaissance that have survived numerous earthquakes as described in Chapters 5 and 11.
Figure 2.1.9. (a) Stalagmitic cavern of Drogarati; (b) Melissani lake (students.ceid.upatras.gr).
(a) (b)
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐8
2.2 Focus Reconnaissance Locations The epicenters of the 2014 earthquakes were located off the southwest coast of the island
for the 1st event and around the town of Lixouri for the 2nd event. The earthquake damage was
mainly concentrated within the Paliki peninsula area, and more specifically in the vicinity of
two of the four main ports of the island, Argostoli and Lixouri. All of our reconnaissance teams
focused their work in that area. Few of the teams extended their visits to towns and ports in the
eastern region to cover the whole island, only to verify that in this area, damage from the
earthquake was negligible. The reconnaissance focus towns and their coordinates are listed in
Table 2.2.1 and mapped on Fig. 2.2.1, where the first map shows the area of significant damage
concentration, and the second the area of no major damage.
Table 2.2.1. Cephalonia focus towns of the GEER/EERI/ATC reconnaissance and their coordinates.
Visited Town
Atheras 38.31794 20.416595
Zola 38.310538 20.469251
Makriotika/ Aghios Gerasimos 38.309041 20.556465
Agkonas 38.301944 20.49036
Kardakata 38.280027 20.469138
Livadi 38.256958 20.422909
Sami 38.251415 20.647169
Aghia Thekli 38.244734 20.385005
Kourouklata 38.243057 20.475852
Vlichata 38.242204 20.393102
Skineas 38.242204 20.393102
Aghios Dimitrios 38.230482 20.429838
Grizata 38.220997 20.645586
Lixouri 38.202221 20.436967
Soullari 38.184739 20.416078
Drapano 38.181888 20.498616
Lepeda 38.178671 20.438256
Vouni 38.178065 20.40316
Kontogennada 38.175368 20.569218
Havdata 38.175368 20.569218
Havriata 38.175368 20.569218
Argostoli 38.173168 20.489973
Aghios Nikolaos 38.167527 20.71506
Poros 38.153965 20.771284
Coordinates
GEER/EERI/ATC Cephalonia, Greece 2014 2‐Cephalonia Island and Areas Covered Report Version 1 2‐9
Figure 2.2.1. Cephalonia locations visited by the GEER/EERI/ATC reconnaissance teams. Top map shows the main focus towns around the Paliki peninsula at the western part of the island where most of the damage was observed. Bottom map shows remaining towns at the eastern part, where minor or no damage was identified.
CHAPTER 3
GEER/EERI/ATC Team
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
3 GEER / EERI / ATC Team The 2014 Cephalonia GEER/EERI/ATC reconnaissance efforts were a collaboration of a
multidisciplinary international team of more than 70 members affiliated with different
institutions, universities and private companies. This Chapter explains the role of each
contributor in this mission and the next chapter explains how the information is presented.
USA TEAM
USA Mission to Cephalonia
The first main shock Mw 6.1 event in Cephalonia on January 26th, 2014 caught the attention
of members of the Geotechnical Extreme Events Reconnaissance (GEER), due to the well-
known history of sequential earthquakes in the island. Consideration was given to the
possibility of a second shock, considering the destructive earthquake sequence of 1953
(described in Chapter 5).
When the second Mw 6.0 event hit Cephalonia on February 3rd, GEER immediately
activated a reconnaissance team, with funding by the National Science Foundation (NSF),
under the leadership of Dr. Sissy Nikolaou, senior associate and director of geo-seismic
department at Mueser Rutledge Consulting Engineers (MRCE) and GEER Advisory Panel
member. The USA team included Professor Dimitrios Zekkos of University of Michigan and
Professor Dominic Assimaki of Georgia Institute of Technology.
At the same time, the Earthquake Engineering Research Institute (EERI) activated its
Learning from Earthquakes (LFE) Program, and in collaboration with the Applied Technology
Council (ATC), supported the USA team with the participation of Mr. Ramon Gilsanz of
Gilsanz Murray Steficek (GMS), board member of EERI-NYNE Chapter and past president of
ATC. Dr. Nikolaou, Dr. Zekkos, and Mr. Gilsanz arrived in Cephalonia on February 7th, 2014.
The USA team met daily with the contributing local teams to coordinate reconnaissance
activities and discuss findings of the previous day. Several of the Greek collaborators were
already on the island and had performed reconnaissance even after the first event. The USA
team spent a week in Greece documenting geotechnical, structural, and nonstructural effects
of the Cephalonia earthquake sequence and organizing the structure and assignments of this
report. The USA team consisted of members of universities, organizations, and private firms,
all listed in this Chapter. External reviewers are denoted by (E).
GEER/EERI/ATC Cephalonia, Greece 2014 3-Reconnaissance Team Version 1 3-1
USA Team Funding Agencies
GEER support was funded in part by NSF Grant No. CMMI-0825734, with key contacts:
GEER Jonathan D. Bray, PE, Faculty Chair in Earthquake Engineering Excellence, University of California at Berkeley, and GEER Steering Committee Chair J. David Frost, PE, Professor, Georgia Institute of Technology and GEER Steering Committee Member Christine Z. Beyzaei, PE, Doctoral Student, University of California at Berkeley, and GEER Recorder
EERI support was funded by the LFE program with key contacts:
EERI Ken Elwood, PhD, Professor, University of British Columbia, EERI Board Member and LFE committee chair Jay Berger, EERI Executive Director Marjorie Greene, EERI Special Projects Manager
ATC supported this mission with key contact:
ATC Chris Rojahn, PE, ATC Executive Director
Collaborating Universities
The following USA universities supported this mission (see also Chapter 4 for roles).
BERKELEY Jonathan D. Bray, PE, Faculty Chair in Earthquake Engineering Excellence, Civil and Environmental Engineering, University of California at Berkeley, CA Christine Z. Beyzaei, PE, Doctoral student
CORNELL Thomas D. O'RourkeE, Hon.D.GE., NAE, Thomas R. Briggs Professor, Civil & Environmental Engineering, Cornell, Ithaca, NY
DREXEL Aspasia ZervaE, Professor, Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, PA
GATECH J. David Frost, PE, Director of GT Savannah & Professor, Civil and Environmental Engineering School, Georgia Institute of Technology
Dominic Assimaki, Associate Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology
ILLINOIS Youssef HashashE, Professor & John Burkitt Webb Endowed Faculty Scholar, Civil & Environmental Engineering, University of Illinois at Urbana-Champaign
UB Andrew WhittakerE, SE, Professor, Chair, Civil, Structural and Environmental Engineering, University at Buffalo, NY Michael C. ConstantinouE, Professor, Civil, Structural, and Environmental Engineering, University at Buffalo, NY
UCLA Jonathan P. Stewart, PE, Professor and Chair, Civil and Environmental Engineering, University of California, Los Angeles
UM Dimitrios Zekkos, PE, Associate Professor, Civil and Environmental Engineering, University of Michigan, Ann Arbor Adda Athanasopoulos-ZekkosE, Assistant Professor, Civil and Environmental Engineering, University of Michigan
Note: E denotes External reviewer GEER/EERI/ATC Cephalonia, Greece 2014 3-Reconnaissance Team Version 1 3-2
USA Engineering Firms
The following private USA engineering firms contributed with staff participation and
offered their resources.
GMS Gilsanz, Murray, Steficek, LLP, New York, NY Ramon Gilsanz, PE, SE, F.SEI, Founding Partner Eugene Kim, PE, Associate Joseph Mugford, PE, Associate Connie Yang, Staff member James Rosenmann, Structural Intern
HDR HDR, Inc. Chris SklavounakisE, PE, Associate Vice President
MAS Mosaic Architectural Solutions, Orange County, CA Philip J. Richter, PE, Principal
MRCE Mueser Rutledge Consulting Engineers, New York, NY Peter W. Deming, PE, Partner, Mueser Rutledge Consulting Engineers, New York, NY Sissy Nikolaou, PhD, PE, Sr. Associate, Geoseismic Dept. Director Michael Law, PhD, PE, GE, Associate Cheryl MossE, Senior Geologist Dimitrios Iliadelis, PE, Senior Structural Engineer Jesse Richins, PE, GE, Senior Geotechnical Engineer Menzer Pehlivan, PhD, Geotechnical Engineer Lysandra Lincoln, Geotechnical Engineer Nonika Antonaki, Geotechnical Engineer Mojtaba Malek, PhD, Structural Engineer Adam Dyer, PE, Geotechnical Engineer Kyriakos Barbagianis, Structural Engineer Allan Amador, Geotechnical Engineer Edward Phelps, Geotechnical Engineer
Note: E denotes External reviewer
GEER/EERI/ATC Cephalonia, Greece 2014 3-Reconnaissance Team Version 1 3-3
GREEK TEAM
The Greek universities and institutions related to the earthquake engineering field
volunteered to participate in this reconnaissance by documenting geotechnical, structural,
nonstructural and socioeconomic effects of the two main Cephalonia earthquake events and
providing information, or acting as external reviewers. Some of the Greek teams had already
been on the island since the first event, while most of the teams joined the USA group and
performed reconnaissance studies after the second event. Several practicing engineers
volunteered their time with representatives on site and participated in data collection and report
preparation. The Greek team is presented by academic, institution, or company affiliation.
Greek Team Funding Agencies
The following funding resources supported some of our Greek team members, with further
details in the Acknowledgments of this report.
ESF and NSRF Achilleas Papadimitriou and Panos Tsopelas of UTH and Nikos Klimis and Manos Psaroudakis of DUTH were co-financed by European Union’s Social Fund (ESF) and Greek national funds through the Operational Program "Education & Lifelong Learning" of the National Strategic Reference Framework (NSRF) – Research Program Thales, Investing in knowledge society through European Social Fund. The UTH members were funded by Thales grant MIS375618: "Mitigation of seismic liquefaction in the foundation soil of existing structures via pore fluid enrichment with environmentally safe nano-particles." The DUTH members were supported by Thales grant ESF Project 85330 entitled: "Characterization of site conditions in Greece for realistic seismic ground motion simulations: pilot application in urban areas."
FORENSEIS George Gazetas of NTUA. Support by Research Project "FORENSEIS" (Investigating Seismic Case Histories and Failures of Geotechnical Systems), implemented under "ARISTEIA" Action of "Operational Programme Education and Lifelong Learning", co-funded by the European Social Fund (ESF) and national resources.
REAKT Dimitris Pitilakis of AUTH-LSDEE. Support by European Research Project “Strategies and tools for Real Time Earthquake Risk Reduction (REAKT) Grant No. 28286
DUTH Nikos Klimis and Manos Psaroudakis of DUTH were funded by the Geotechnical Division of Civil Engineering Dept. of Democritus University of Thrace, in addition to the support by ESF/NSRF above.
TEE George Bouckovalas & Ioannis Psycharis of NTUA were funded by the Technical Chamber of Greece (TEE) for their reconnaissance visits.
UB-UK George Mylonakis of UPATRAS was funded for his travel by the Queens School of Engineering of the University of Bristol.
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Collaborating Greek and European Universities
The following universities (listed alphabetically) supported this mission and report with
participation of members whose role is explained in Chapter 4.
ASPETE School of Pedagogical & Technological Education, Athens Panagiotis Pelekis, Associate Professor, Department of Civil Engineering Educators Vagelis Plevris, Assistant Professor of Earthquake Engineering, Department of Civil Engineering Educators
AUTH Aristotle University of Thessaloniki, Greece Costas Papazachos, Professor of Geophysics, School of Geology, Department of Geophysics Spyros B. Pavlides, Professor of Neotectonics and Palaeoseismology, Department of Geology Alexandros Chatzipetros, Lecturer, Department of Geology George Papathanassiou, Postdoctoral Researcher, Laboratory of Engineering Geology, Department of Geology
AUTH-DSE AUTH, Division of Structural Engineering, Greece Anastasios G. Sextos, Assistant Professor
AUTH-LSDGEE AUTH, Lab of Soil Dynamics & Geotechnical Earthquake Engng Dimitris Pitilakis, Assistant Professor Kyriazis Pitilakis, Professor Anna Karatzetzou, Doctoral Candidate Konstantinos Mouratidis, Researcher
DUTH Democritus University of Thrace, Civil Engineering Dept., Greece Nikolaos Klimis, Associate Professor, Head of Laboratory of Soil Mechanics & Foundation Engineering Manos Psaroudakis, Civil Engineer DUTH, MSc UPatras
HUA Harokopion University of Athens, Greece Issaak Parcharidis, Associate Professor in Remote Sensing, Department of Geography
NTUA National Technical University of Athens, Greece George Gazetas, Professor, Director of Soil Mechanics and Dynamics Laboratory, School of Civil Engineering Elli Vintzilaiou, Professor, Director of Structural Engineering, School of Civil Engineering George BouckovalasE Professor, Department of Geotechnical Engineering, School of Civil Engineering Ioannis Psycharis, Professor of Earthquake Engineering, Department of Structural Engineering, School of Civil Engineering Harris Mouzakis, Assistant Professor, Department of Structural Engineering, School of Civil Engineering Vasilis Tsouras, Associate Professor, Architectural Research Unit
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Evaggelia Garini, Postdoctoral Researcher, Soil Mechanics and Dynamics Laboratory, School of Civil Engineering Tilemachos Beriatos, Professional Civil Engineer Alkis Papathanasiou, Professional Civil Engineer Kostas Rouchotas, Professional Civil Engineer
TU-K Technical University of Kaiserslautern, Germany
Christos VrettosE, Professor and Director of Soil Mechanics and Foundation Engineering Division
UPATRAS University of Patras, Department of Civil Engineering, Greece George Athanasopoulos, Professor of Geotechnical Engineering Stephanos Dritsos, Professor of Structural Engineering Nicos MakrisE, Professor of Structural Engineering George Mylonakis, Professor of Geotechnical Engineering Costas Papantonopoulos, Associate Professor of Geotechnical Engineering Anastasios Batilas, Doctoral Candidate Xenia Karatzia, Doctoral Candidate Vasileios Kitsis, Doctoral Candidate Fotini Lyrantzaki, Doctoral Candidate Stavroula Skafida, Doctoral Candidate Vasileios Vlachakis, Doctoral Candidate Elpida Katsiveli, Postgraduate Student Olga Theofilopoulou, Postgraduate Student Eva Agapaki, Undergraduate Student
UTH University of Thessaly, Department of Civil Engineering, Greece Marina Moretti, Assistant Professor of Structural Engineering Achilleas G. Papadimitriou, Assistant Professor of Geotechnical Engineering Panos Tsopelas, Professor of Structural Dynamics and Earthquake Engineering
Note: E denotes External reviewer
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Greek Engineering Firms
The following private engineering firms contributed with staff participation and offered resources.
DIA Diatonos Mechaniki, Nafpaktos, Greece Fotis G. Pantelis, Professional Civil Engineer, Founder and Owner Dionysios Ch. Moschonas, Professional Civil Engineer Katerina Ch. Sypsa, Professional Civil Engineer
EF Easy Facilities SA, Athens, Greece Angeliki Psychogiou, Managing Director and President George Tsakalias, Vice President Dimitris Kopanos, Professional Civil Engineer, Project Manager
GENG Geoengineer.org, Athens, Greece Dimitrios Zekkos, PhD, PE, Founder Vasiliki Dimitriadi, Geotechnical Engineer Ilias Giannoutsos, IT division Kostis Tsantilas, IT division
OTM Omilos Technikon Meleton, SA, Athens, Greece Aris Gazetas, Professional Civil Engineer
Public Organizations
The following Greek public organizations contributed significantly in numerous ways.
LEEPKA 35th Ephorate of Prehistoric and Classical Antiquities Antonis Petropoulos, Professional Civil Engineer
EPPO-ITSAK Institute of Engineering Seismology & Earthquake Engineering Christos Karakostas, PhD, Research Director Vassilios Lekidis, PhD, Research Director Konstantia Makra, PhD, Senior Researcher Basil Margaris, PhD, Researcher Konstantinos Morfidis, PhD, Researcher Christos Papaioannou, PhD, Research Director Manos Rovithis, PhD, Researcher Thomas Salonikios, PhD, Senior Researcher Alexandros Savvalidis, PhD, Senior Researcher Nikos P. Theodulidis, PhD, Researcher
NOA-IG National Observatory of Athens-Institute of Geodynamics Ioannis Kalogeras, PhD, Seismologist and Researcher Director Melis N., PhD, Research Director Evangelidis C., PhD, Assistant Researcher Ganas A., PhD, Research Director Papanikolaou M., Associate of IG
EYDAP The Athens Water Supply and Sewerage Company George Sachinis, Head of Operations Kostas Papadakis, Supervisor, Electromechanical Department Cleio Eleutheriou, Head of Water Operations
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PROFESSIONAL SOCIETY AND INSTITUTIONS MEMBERS
This reconnaissance mission brought together professionals of multidisciplinary
backgrounds, affiliated with various professional societies listed below. The team included 13
members of GEER, 32 members of EERI, 2 past presidents and the executive director of ATC,
15 members of Seismological Society of America (SSA), and 25 members of Hellenic Society
of Earthquake Engineering (ETAM). Additionally, US Geological Survey (USGS),
Multidisciplinary Center for Earthquake Engineering Research (MCEER), and Structural
Engineering & Earthquake Simulation Laboratory (SEESL) were represented.
GEER Bray J.D., Steering Committee chair Frost J.D., Steering Committee member O'Rourke T.D., Advisory Panel Member Nikolaou S., Advisory Panel Member Assimaki D., Member Athanasopoulos-Zekkos A., Member Hashash Y., Member Papaioannou C., Member Papathanassiou G., Member Pitilakis D., Member Stewart J.P., Member Zekkos D., Member Christine Z. Beyzaei, Recorder
EERI Ken Elwood, EERI Board Member and LFE Committee Chair Stewart J.P., LFE Advisory Committee, Earthquake Spectra Editor
Jay Berger, EERI Executive Director Marjorie Greene, EERI Special Projects Manager Antonaki N., Student Member
Assimaki D., Member Barbagianis K., MemberS Deming P.W., MemberS Dyer A., MemberS Gazetas G., Member Gilsanz R., MemberS, NYNE Chapter Board Member Hashash Y., Member Iliadelis D., MemberS Kim E., MemberS Lekidis, V., Member Lincoln L., MemberS, NYNE Chapter Event Coordinator Makris N., Member Malek M., MemberS Moss C.J., MemberS Mugford E., MemberS Mylonakis G., Member Nikolaou S., MemberS, NYNE Chapter President, IDC Committee
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Papaioannou Ch., Member Pehlivan M., MemberS, NYNE Chapter Academic Liaison Psycharis I.N., Member Richins J., MemberS, NYNE Chapter Board Member, Treasurer Richter P., Member Rosenmann J., Student Member
Sextos A., Member Yang C., MemberS Zekkos D., Member Zerva, A., Member Note: S denotes Subscribing firm
ATC Rojahn C., Executive Director Gilsanz R., Past President Richter P.J., Past President
SSA Assimaki D., Member Deming, P., Member Evangelidis C., Member Gazetas G., Member Hashash Y., Member Kalogeras I., Member Margaris B., Member Melis N., Member Mylonakis G., Member Nikolaou S., Member Papadimitiou A., Member Papaioannou Ch., Member Stewart J.P., Member Theodulidis N., Member Zerva, A., Member
ΕΤΑΜ Pitilakis K., President Vintzilaiou E., Vice President Sextos A., Secretary Gazetas G., Board Member Psycharis I.N., Board Member Bouckovalas G., Member Garini E., Member Karatzetzou A., Member Klimis N.S., Member Lekidis V., Member Makra, K., Member Makris N., Member Margaris B., Member Moretti M., Member Mouzakis H., Member Mylonakis G., Member Nikolaou S., Member Papathanasiou A., Member Pitilakis D., Member
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Plevris, V., Member Rovithis M., Member Theodoulidis N., Member Tsopelas P., Member Vrettos Ch., Member
USGS Holzer T., Senior Geologist Leith W., Senior Science Advisor & NEHRP Secretariat
MCEER Whittaker A., Director
SEESL Constantinou M.C., Deputy Director
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CHAPTER 4
Technical Documentation
and Contributions
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4 Documentation and Contributions The 2014 Cephalonia events revealed invaluable technical information in a broad range
of topics of interest to earthquake engineering and public safety. In this chapter, we explain
the technical information obtained through reconnaissance and how this information is
presented in this report.
The 2014 Cephalonia GEER/EERI/ATC reconnaissance efforts were a collaboration of
a multidisciplinary team of more than 70 members affiliated with different institutions,
universities and private companies. The Greek earthquake engineering community
practically came together for this effort, either as participant in the field, co-author or co-
editor of the report, or external reviewer. This community is highly qualified and has
historically made significant contributions to the field of earthquake engineering. An
impressive number of members of GEER (13), EERI (32), ATC (3), SSA (15) and Greek
ETAM (25) were included, many in leadership positions in these organizations.
The amount of information collected was substantial, so chapters were divided in
sections with specific technical focus within the topic of the chapter. The technical part of
the report is essentially covered in chapters 2 and 5 to 12. The content of each technical
chapter and its sections are presented here, along with the names of the dedicated people
who contributed with authorship capacity in its preparation. Contributing authors of each
section are listed with their institution affiliation. The institutions appear in alphabetical
order, and the names of contributing authors are listed in the order provided by their
institutions to the editors. Where co-editors are listed as co-authors, it means that their work
went beyond the editorial task into an actual contribution in the content of a section.
External reviewers are listed at the end of their section, with the editorial note that in large
part the external review work is ongoing and will be completed in the next version. In many
sections, the contributions were large and complex enough to grant the need to have
dedicated leaders that put the material together before it was delivered to the editors. For
these sections, the leader or co-leaders are indicated by an asterisk (*).
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CHAPTER 2 CEPHALONIA HISTORY AND AREAS COVERED
This chapter gives background on the Cephalonia island including a roadmap to names, location, and coordinates of the towns that were the focus of reconnaissance, prepared by:
GATECH Dominic Assimaki MRCE Sissy Nikolaou, Nonika Antonaki, Dimitrios Iliadelis UMICH Dimitrios Zekkos
CHAPTER 5 SEISMIC HISTORY AND HAZARD
Section 5.1 presents a review of history of earthquakes, their impact and seismic hazard mapping of Cephalonia. Section 5.2 is in progress and will present comparisons of intensity distributions to regional probabilistic hazard studies. Chapter 5 is authored by:
EPPO – ITSAK Christos Papaioannou
CHAPTER 6 GEOLOGY AND SEISMOTECTONICS
6.1 Geology and Geomorphology. The geology, geomorphology, faulting, and sea reclamation history of Cephalonia island are provided with contributing authors:
AUTH Alexandros Chatzipetros (*), Spyros Pavlides (*) MRCE Sissy Nikolaou, Menzer Pehlivan
External reviewer: MRCE Cheryl J. Moss
6.2 Seismotectonics. This section is in progress regarding seismotectonic mechanisms, geometry of ruptured area, and epicenter locations. The authors of this section are:
EPPO-ITSAK Basil Margaris AUTH Costas Papazachos
CHAPTER 7 SEISMOLOGICAL AND STRONG MOTION ASPECTS
7.1 First Main Event of January 26, 2014. The station network and strong ground motion records are presented. Section 7.2 is underway with seismological details of the 2nd event of February 3, 2014 (currently plots of selected records are shown, provided by P. Pelekis and G. Athanasopoulos). The co-authors of Sections 7.1 and (upcoming) 7.2 are:
ASPETE Panagiotis Pelekis EPPO-ITSAK Basil Margaris, Christos Papaioannou,
Alexandros Savvaidis and Nikos Theodouldis NOA-IG Ioannis Kalogeras, Nicos Melis, Christos Evangelidis UCLA Jonathan Stewart UPATRAS George Athanasopoulos, George Mylonakis,
Vasileios Vlachakis, Anastasios Batilas
7.3 Remote Sensing Interferometry. Remote sensing interferometry after the 2nd main event are presented in this section, with lead author I. Parcharidis in collaboration with:
HUA Issaak Parcharidis (*) MRCE Lysandra Lincoln, Menzer Pehlivan NTUA George Gazetas
For Chapter 7, external reviewer is: DREXEL Aspasia Zerva
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CHAPTER 8 GEOTECHNICAL OBSERVATIONS
8.1 Site Effects. Possible amplification and topographic effects based on few data and comparisons with codes were compiled by lead authors D. Assimaki and G. Gazetas, with:
AUTH George Papathanasiou GATECH Dominic Assimaki (*) MRCE Menzer Pehlivan, Sissy Nikolaou NTUA George Gazetas (*) UTH Achilleas Papadimitriou
External reviewers: DREXEL Aspasia Zerva ILLINOIS Youssef Hashash
8.2 Liquefaction, Ports and Waterfront. Observations with focus on the ports of Lixouri, Argostoli, and Sami and the broader Paliki peninsula are compiled under the leadership of D. Zekkos, G. Athanasopoulos, and G. Mylonakis, with their co-authors:
ASPETE Panagiotis Pelekis AUTH George Papathanasiou, Sotiris Valkaniotis, Spyros Pavlides AUTH-LSDGEE Kyriazis Pitilakis, Dimitris Pitilakis, Anna Karatzetzou,
Konstantinos Mouratidis EPPO-ITSAK Konstantia Makra, Manos Rovithis, Alexandros Savvaidis GATECH Dominic Assimaki GENG Vasiliki Dimitriadi MRCE Menzer Pehlivan, Sissy Nikolaou NOA-IG Athanasios Ganas, Marios Papanikolaou NTUA George Gazetas, Evangelia Garini, Kostas Rouchotas ROUCH Lefteris Rouchotas UMICH Dimitrios Zekkos (*) UPATRAS George Athanasopoulos (*), George Mylonakis (*), Anastasios
Batilas, Xenia Karatzia, Vasileios Kitsis, Fotini Lyrantzaki, Stavroula Skafida, Olga Theofilopoulou, Vasileios Vlachakis
UTH Achilleas Papadimitriou External reviewers:
NTUA George Bouckovalas UMICH Adda Athanasopoulos-Zekkos
8.3 Earth Retaining Structures. Section 8.3 summarizes the performance of earth, masonry, and concrete retaining walls, compiled by:
AUTH-LSDGEE Dimitris Pitilakis, Anna Karatzetzou, Konstantinos Mouratidis DUTH Nikolaos Klimis, Manos Psaroudakis EPPO-ITSAK Manos Rovithis and Konstantia Makra MRCE Jesse Richins NTUA George Gazetas and Evangelia Garini UMICH Dimitrios Zekkos (*) UPATRAS George Athanasopoulos (*), Olga Theofilopoulou, Vasileios Kitsis,
Stavroula Skafida, Vasileios Vlachakis, Anastasios Batilas, Costas Papantonopoulos, Eva Agapaki, Elpida Katsiveli, George Mylonakis
UTH Achilleas Papadimitriou
External reviewer: TU Kaiserslautern Christos Vrettos
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8.4 Landslides and Rockfalls. Earth landslides, embankment settlements and rock failures were prepared by leaders C. Papantonopoulos and G. Mylonakis with co-authors:
AUTH-LSDGEE Dimitris Pitilakis DUTH Nikolaos Klimis, Manos Psaroudakis EPPO-ITSAK Manos Rovithis, Konstantia Makra GATECH: Dominic Assimaki MRCE Jesse Richins, Sissy Nikolaou NTUA George Gazetas, Evangelia Garini, Telemachos Beriatos UPATRAS Costas Papantonopoulos (*), George Mylonakis (*),
Eva Agapaki, Elpida Katsiveli UTH Achilleas Papadimitriou
External reviewer: NTUA George Bouckovalas
8.5 Bridges. Observations compiled by A. Papadimitriou and contributions by: AUTH-LSDGEE Kyriazis Pitilakis EPPO-ITSAK Manos Rovithis, Konstantia Makra GATECH: Dominic Assimaki MRCE Sissy Nikolaou, Menzer Pehlivan UTH Achilleas Papadimitriou (*)
External reviewers: DREXEL Aspasia Zerva HDR Chris Sklavounakis
8.6 Embankments and Landfills. Road embankments and landfills observations were compiled by A. Papadimitriou with his co-authors:
AUTH-LSDGEE Dimitris Pitilakis, Anna Karatzetzou DUTH Nikolaos Klimis. Manos Psaroudakis EPPO-ITSAK Manos Rovithis, Konstantia Makra MRCE Jesse Richins, Nonika Antonaki UMICH Dimitrios Zekkos UPATRAS George Athanasopoulos, Olga Theofilopoulou, Vasileios Kitsis UTH Achilleas Papadimitriou (*)
External reviewer: TU Kaiserslautern Christos Vrettos
8.7 Settlement and Soil-Structure Interaction. Performance of 10 documented structures with focus on SSI effects were prepared under the leadership of G. Mylonakis with the following co-authors:
AUTH-DSE Anastasios Sextos DIA Katerina Sypsa EF Dimitri Kopanos MRCE Sissy Nikolaou UMICH Dimitrios Zekkos UPATRAS George Mylonakis (*), George Athanasopoulos, Anastasios Batilas, Xenia Karatzia, Vasileios Kitsis, Fotini Lyrantzaki,
Olga Theofilopoulou, Vasileios Vlachakis UTH Achilleas Papadimitriou
External reviewer: TU Kaiserslautern Christos Vrettos
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CHAPTER 9 RIGID BLOCKS
Chapter 9 presents a synthesis of the findings of all reconnaissance teams regarding rigid block response including types of damage, controlling parameters and spatial distribution of damage compiled under the leadership of George Gazetas with contribution of the following co-authors:
AUTH-LSDGEE Dimitris Pitilakis, Anna Karatzetzou, Konstantinos Mouratidis DIA Fotis Pantelis, Dionysios Moschonas, Katerina Sypsa DUTH Nikolaos Klimis and Manos Psaroudakis EPPO-ITSAK Manos Rovithis, Konstantia Makra MRCE Sissy Nikolaou, Menzer Pehlivan NTUA George Gazetas (*), Evangelia Garini, Telemachos Beriatos,
Kostas Rouchotas UMICH Dimitrios Zekkos UPATRAS George Mylonakis, George Athanasopoulos, Costas
Papantonopoulos, Eva Agapaki, Olga Theofilopoulou, Elpida Katsiveli, Vasileios Kitsis
UTH Achilleas Papadimitriou
9.2 Detailed Reconnaissance; 9.3 Statistics of Failures in Cemeteries. These sections of Chapter 9 present detailed reconnaissance data from cemeteries and monuments. The above team members are co-authors in their compilation, prepared under the leadership of:
AUTH-LSDGEE Dimitris Pitilakis (*), Anna Karatzetzou, Konstantinos Mouratidis
For Chapter 9, external reviewer is: UPATRAS Nicos Makris
CHAPTER 10 INFRASTRUCTURE NETWORKS
10.1 Potable and Wastewater Networks. Section 10.1 presents the EYDAP Organization, the action plan, and restoration of damaged potable and wastewater networks after both events. Contributing authors of this section are as listed below:
EYDAP Kostas Papadakis, Cleio Eleutheriou
Translation and editorial compilation was performed by:
MRCE Dimitrios Iliadelis, Sissy Nikolaou UMICH Dimitrios Zekkos
External reviewers are: CORNELL Thomas D. O’Rourke ILLINOIS Youssef Hashash
10.2 Transportation Road Network. Section 10.2 presents observations related to road transportation network performance and traffic disruptions during the two main seismic events and their aftershocks. Contributing authors of this section are as listed below:
MRCE Dimitrios Iliadelis, Sissy Nikolaou UTH Achilleas Papadimitriou (*)
External reviewer is: HDR Chris Sklavounakis
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CHAPTER 11 STRUCTURAL OBSERVATIONS
The multiple contributions in Chapter 11, particularly Sections 11.1 to 11.7, were edited by P. Tsopelas of UTH prior to submittal to the editors.
11.1 Main Structural Observations. Typical structural damage in Paliki peninsula by:
NTUA Ioannis Psycharis
11.2 Building Inventory and Construction Types. This section presents building types according to load bearing system by co-authors:
EPPO-ITSAK Vassilis Lekidis, Thomas Salonikios, Christos Karakostas, Kostas Morfidis
11.3 Damage Assessment. Surveys and assessment data are summarized by:
GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford MRCE Dimitrios Iliadelis, Lysandra Lincoln OTM Aris Gazetas UPATRAS Stefanos Dritsos (*) UTH Marina Moretti (*)
11.4 Typical Damage Patterns by Construction Type. Section 11.4 presents structural observations for masonry, reinforced concrete, and other buildings per era of construction with contributions by:
NTUA Ioannis Psycharis (*), Elli Vintzilaiou (*), Alkis Papathanasiou GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford MRCE Dimitrios Iliadelis, Sissy Nikolaou UTH Panos Tsopelas
11.5 Structural Behavior Based on Seismic Codes. A brief review of Greek seismic codes with comparison to US codes is presented, along with observations based on seismic code effective at year of construction. Contributing authors of this section are:
AUTH-DSE Anastasios Sextos ASPETE Vagelis Plevris EPPO-ITSAK Thomas Salonikios, Vassilis Lekidis, Christos Karakostas,
Kostas Morfidis GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford MRCE Dimitrios Iliadelis, Sissy Nikolaou, Mojtaba Malek UTH Panos Tsopelas (*), Marina Moretti (*)
11.6 Special Cases of Structural Interest. This section presents structural observations for structures with multiple additions, public low income housing, typical available drawings and building instrumentation, by the following co-authors:
ASPETE Vagelis Plevris AUTH-DSE Anastasios Sextos EPPO-ITSAK Vassilis Lekidis, Christos Karakostas DIA Fotis G. Pantelis GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford MRCE Dimitrios Iliadelis, Sissy Nikolaou UTH Panos Tsopelas (*), Marina Moretti
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11.7 Public Buildings. Reconnaissance information for public administrative, critical, and school structures are compiled by the lead author A. Sextos and his co-authors:
AUTH-DSE Anastasios Sextos (*) GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford LEEPKA Antonis Petropoulos MRCE Sissy Nikolaou, Dimitrios Iliadelis UTH Marina Moretti
11.8 Churches. Classification, damage rating, and performance of churches are compiled by H. Mouzakis and participation of his co-authors:
AUTH Anastasios Sextos EPPO-ITSAK Vassilis Lekidis, Thomas Salonikios, Kostas Morfidis LEEPKA Antonis Petropoulos NTUA Haris Mouzakis (*), Elli Vintzilaiou, Vasilis Tsouras
11.9 Nonstructural Components. Observations of damage to nonstructural components in buildings that did not have significant damage with contributions by:
DIA Fotis G. Pantelis, Dionysios Ch. Moschonas, Katerina Ch. Sypsa EF George Tsakalias (*), Dimitris Kopanos, Angeliki Psychogiou GMS Ramon Gilsanz, Eugene Kim, Joseph Mugford MRCE Sissy Nikolaou, Lysandra Lincoln, Peter Deming OTM Aris Gazetas
For the entire Chapter 11, external reviewers are:
ATC/MAS Philip J. Richter NYCDOB Gus Sirakis UB Michael Constantinou UB Andrew Whittaker
CHAPTER 12 COMMUNITY PREPAREDNESS AND RESPONSE
Chapter 12 presents results of damage assessment surveys, government response and offered financial aid, earthquake insurance data, and provided community housing and support. Contributing authors of this section are as listed below:
EF George Tsakalias, Angeliki Psychogiou GATECH Dominic Assimaki GMS Ramon Gilsanz MRCE Nonika Antonaki, Sissy Nikolaou, Dimitrios Iliadelis UMICH Dimitrios Zekkos UPATRAS Stefanos Dritsos UTH Marina Moretti
CHAPTER 5
Seismic History and Hazard
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5.1 Historical Earthquakes INTRODUCTION
Cephalonia has a remarkable seismic history which can be traced back to antiquity. This
section presents macroseismic data and the high historic seismicity of the region. The effects
of the 18 strongest earthquake events (6.3 ≤ M ≤ 7.4) since the middle of the 15th century are
listed. The main seismotectonic feature of the greater geographic region of Cephalonia, the
Central Ionian Islands area, is the Cephalonia Transform Fault (CTF) is shown on Figure 5.1.1
(Scordilis et al., 1984) and also discussed in the Geology Section (6.1) of this report.
Figure 5.1.1. Key seismotectonic features of the broader Aegean area. The Cephalonia Transform Fault (CTF) is shown within the black rectangle (modified after Scordilis et al., 1984).
Current ongoing studies compare observed and theoretically estimated intensity
distributions from historical records to regional probabilistic seismic hazard studies. Findings
of these studies will be incorporated in a future version of this report.
CTF
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HISTORIC SEISMIC HAZARD MAPPING
The Cephalonia island has been located within the highest seismic zoning in all revisions
of seismic hazard mapping of Greece. Three versions of such maps, dated from 1939 to 2001
are presented on Figure 5.1.2.
Figure 5.1.2. Seismic hazard maps of Greece published in: (a) 1939; (b) 1995; and (c) 2001 (referenced in current Greek Seismic Code). Cephalonia region shown in dashed green rectangle.
(a) (b)
(c)
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The first seismic hazard map of Greece was published in 1939 in the Technical Chronicles
Magazine (Vol. 184). Shown on Figure 5.1.2a, the 1939 mapping assigned 3 different zones to
Cephalonia with design acceleration values ranging from 0.08 to 0.16 g. A revised version of
this map was adopted in the seismic code of 1956 which included the Aegean sea islands of
Dodecanese that merged with Greece after World War II. The seismic hazard zonation of Figs.
5.1.2b, c formed the basis for the 1995 and current national seismic codes, respectively.
HISTORIC EARTHQUAKE RECORDS [14691983]
Recognizing the importance of historical macroseismic observations in evaluating seismic
hazard and mitigating seismic risk, the Geophysical Laboratory of the Aristotle University of
Thessaloniki (AUTH), has been archiving macroseismic data since the 1980s. Papazachos and
Papazachou (1989) have published a catalogue of strong earthquakes (M>6.0) in the Aegean
and surrounding area between 550 BC and 1986. Papazachos et al. (1997a,b) successively
published an updated catalogue of these earthquakes including macroseismic data from
bulletins of the Observatory of Athens (1900-1939 and 1950-1996) resulting into a database of
37,000 macroseismic observations from 900 earthquakes. The database has proven invaluable
for studies on attenuation relations, development of synthetic isoseismal maps, estimating
upper bound intensity of rupture zones, and performing probabilistic seismic hazard studies
(Papazachos and Papaioannou, 1998; Papazachos et al., 1998).
Using information from this database, the regional seismic hazard map based on
macroseismic intensity observations over the past six centuries is currently being revised,
specifically incorporating use of: (i) macroseismic intensity to estimate the magnitude and
epicenter of the causative earthquake for each historic reference, and (ii) early analogue
recordings to estimate source parameters of several strong events from the past 150 years.
Earthquake information for the 18 strongest (M 6.0) historical events of magnitude
between 6.3 and 7.4 since the second half of the 15th century AD, are summarized on Table
5.1.1 and discussed in the following paragraphs. Historic data of earthquakes with available
macroseismic intensities at long distances (low intensities) were used and macroseismic effects
at short distances. The low intensities were used to calculate the earthquake magnitude and the
scaling relation by Papazachos & Papaioannou (1997) was applied to assess the macroseismic
intensity near the epicenter. Since macroseismic effects on old buildings near the epicenter are
known, a relation between them and the intensity estimated in a modern macroseismic scale
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was attained. Generally, these effects correspond to the five high intensities of the Modified
Mercalli (MM) scale, shown on Table 5.1.2. Available macroseismic intensities were used to
determine the maximum macroseismic intensity, Io, at the center of the rupture zone using the
Papazachos (1992) methodology, which showed that all historic events had Io VIII, while
recorded earthquakes after 1960 had an Io cutoff value of VI.
Table 5.1.1. Information on source parameters of strong (M≥6.0) earthquakes in the area of Cephalonia from 1469 to 1983 (Papazachos and Papazachou, 2003).
DateTime
1469 Spring 38.30 20.50 7.2 Cephalonia IX
1636 30-Sep IXmidnight (Makropoulo)
1638
IX(Lixouri)
X(Lixouri)
February 4 X4:19 (Lixouri)
January 24 X16:22:51 Asprogerakas
January 27 IX1:09:56 (Exogi)
August 715:04:03August 12 X+
9:23:52 (Argostoli)September 17 VII
14:07:15 (Chavriata)January 17 VI12:41:31 (Argostoli)
Year Latitude Longitude Magnitude
1658
16-Jul
August 24 38.20 20.40
38.20 20.40
38.10 20.30
August 28 38.10 20.501714
1741
1759
June 23
June 13
38.15 20.40
1912 38.11 20.67 6.8
1867 38.39 20.52 7.4
1766
1767
1862
July 24
38.30 20.40 6.5March 14
1915
1915
1953
38.36 20.60 6.6
38.50 20.62 6.7
1972
1983 38.10 20.20 7.0
Locality max Intensity Io
Cephalonia
Cephalonia
Cephalonia
Cephalonia 7.0
VIII
Cephalonia VIII6.4
6.4
7.2
38.21 20.31 6.3
6.4
38.20 20.50 6.3
July 22
38.10 20.40 7.0
38.30 20.40 7.2
Lixouri VIII
Argostoli VIII
Cephalonia IX
38.30 20.80 7.2 Cephalonia
Cephalonia
Cephalonia
Ithaca
Ithaca IX
Cephalonia
Argostoli IX
Cephalonia
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Table 5.1.2. Modified Mercalli (MM) intensities and corresponding effects.
Figure 5.1.3 shows the spatial distribution of epicenters of the earthquakes in Table 5.1.1.
Colored circles represent data of the early instrumental period (after 1900), while grey circles
show epicenters of the historical (prior to 1900) period. Clearly most of the epicenters are at
the western part of the island. Key features and references for these events are provided in the
following paragraphs.
Figure 5.1.3. Epicenters of strong (M ≥ 6.0) earthquakes at the broader area of Cephalonia since 1469. Historical events in gray circles and instrument-based epicenters in colored circles.
MM Intensity Effect
Intensity VIICracks (fissures) in many structures (houses, walls, castles, etc). Minor damage in several structures. Collapse of some weak structures and non-structural components.
Intensity VIIISignificant damage in many structures. Destruction of several structures. Collapse of some ordinary structures.
Intensity IX Extensive damage. Destruction of many structures. Collapse of several structures.
Intensity X Extensive destructions. Collapse of many structures.
Intensity XI Collapse of almost all structures.
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1469, Spring season, 38.3o N, 20.5o E, h = n, M 7.2, Cephalonia (IX)
According to Papazachos & Papazachou (2003), information for the 1469 strong
earthquake is given by George Frangis and other sources (Aravantinos, 1856; Barbiani &
Barbiani, 1864). In the spring of 1469, numerous earthquakes occurred and were strongly felt
in the Ionian islands of Lefkada, Cephalonia and Zante (Zakynthos), with disastrous effects.
Many of the state buildings collapsed killing many of the inhabitants. In Cephalonia, the walls
were entirely destroyed and a small town entirely collapsed. The 1469 shock was felt in Epiros.
Aftershocks continued for many months and kept the inhabitants at unrest.
1636, September 30, 38.1o N, 20.3o E, h = n, M 7.2, Cephalonia (IX, Makropoulo)
The 1636 earthquake caused severe destruction in Cephalonia based on Papazachos &
Papazachou (2003). It devastated the villages Eikosmia, Eleio, Makropoulo, Valta, Koronoi,
Solomata, Heraklio, and Pyrgio. In the mountain Ainos many trees were uprooted, while the
chapel of Aghios Eleftherios remained undamaged. Omala experienced minor damage, but the
area around the fortress, including Livatho, Argostoli, and Lixouri, suffered significant
damage. The earthquake caused rockslides and the Acropolis to sink in the sea at the location
where Kakkava appears. 520 people lost their life. A captain of a ship observed an intense sea
wave out of Cephalonia. The aftershocks continued up to the spring of 1637 (Perrey, 1848;
Mallet, 1854; Schmidt, 1867a; Partsch, 1890; Romas, 1975).
1638, July 16, 38.2o N, 20.4o E, h = n, M 6.4, Cephalonia (VIII)
Based on Papazachos & Papazachou (2003), a note in the historical record of Cephalonia
(Pentogalos, 1973; Mouyiaris, 1994) mentioned that the 1638 earthquake completed the
disaster of the 1636 earthquake. It completely destroyed the buildings which survived the 1636
earthquake and several new structures and resulted in the collapse of the archiepiscopate
building.
1658, August 24, 38.2o N, 20.4o E, h = n, M 7.0, Cephalonia (IX, Lixouri)
Similar to the 2014 events, the 1658 earthquake hit the Paliki peninsula as described in
Papazachos & Papazachou (2003) based on information by Schmidt (1867), Partsch, (1890)
and Tsitselis (1960). In Lixouri, 500 houses collapsed and 20 people were killed. In the month
following the mainshock, almost all village houses in the peninsula area collapsed and about
300 more people died. A whole hill with a church disappeared and the monastery of Gera was
severely damaged.
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1714, August 28, 38.1o N, 20.5o E, h = n, M 6.4, Cephalonia (VIII)
Reports by Barbiani and Barbiani (1864) and Chiotes (1886-87) summarized in Papazachos
& Papazachou (2003) state that the 1714 earthquake of Cephalonia was very strong and caused
overturn and collapse of about 280 houses. Gaps were evident on the earth’s surface at several
locations and new hot springs were created. The inhabitants stayed outdoor for two months.
Albini et al. (1994) states that “A damaging earthquake in Cephalonia is mentioned in a
18th century history of Epirus (Michael, XVIII) after the earthquake in Patras of 27 July 1714
[Old Style Julian calendar, OS]. On 28 August 1714 (OS), another more dreadful earthquake
occurred in Cephalonia, where the Venetian admiral was at anchor with his fleet. The earth
opened, hot water flowed out; 280 houses were destroyed, water issued from the earth, and the
inhabitants lived two months in the gardens”. However, this event has not been mentioned in
the examined contemporary dispatches originating from the Ionian Islands and addressed to
the Venetian authorities (Daltri & Albini, 1991).
Table 5.1.3. Venetian documentary sources of information regarding the Ionian islands, available from the State Archives of Venice (ASVe, 1712-1764). Modified from Albini, et al. (1994).
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The Provveditore Generale da Mar Agostino Sagredo stayed for some time in Morea and
was back in Corfu on August 20th, according to the Venice State Archives (ASVe, 1714a). He
was substituted by Daniele Dolfin, who visited Cephalonia early in October (ASVe, 1714b).
In that period the Venetian governors were focused on the war with the Ottoman Empire for
the control of Morea. There is no mention of this earthquake in the dispatches and letters of the
Provveditore of Cephalonia and of the consul in Patras to the Cinque Savi alla Mercanzia
(ASVe, 1693-1722; ASVe, 1712-1764) presented in Table 5.1.3 (Albini et al., 1994). The
earthquake was reported in the European press (Theatrum Europaeum, 1714) where the events
in Patras and Cephalonia are amalgamated into one shock dated September 3rd, 1714 N.S.
(referring to New Style Julian Calendar, N.S.). This erroneous information is repeated by other
contemporary sources (Amato, 1715).
1741, June 23, 38.15o N, 20.40o E, h = n, M 6.4, Lixouri (VIII)
Papazachos & Papazachou (2003) report that the earthquake destroyed houses in the
northwest part of Cephalonia, especially in Lixouri, Argostoli, and Kastro (Aghios George).
The parochial temple in Lixouri was completely destroyed in addition to some public buildings.
In the fortress of Assos, many buildings collapsed and the remaining were severely damaged.
The aftershocks continued for five months causing extra damages in the west part of
Cephalonia (Albini et al., 2000). Albini et al (1994) states that “On 23 June 1741 (N.S.) an
earthquake affected the Ionian Islands” In the southwest part of the Cephalonia Island, all the
houses, particularly those in the districts of Lixouri, Argostoli, and Borgo (Castro, now called
Aghios Georgios) were shattered. The parish church of Lixouri collapsed, as did a number of
public buildings. In the fort of Assos many dwellings collapsed and the rest of the buildings
were ruined, apparently without loss of lives (ASVat, 1743a). Venetian documents do not
supply the date and briefly describe the damage in Argostoli and in the Assos Fortress (ASVe,
1741b). There is no evidence that the earthquake was felt elsewhere. It was followed by
aftershocks that continued intermittently for five months (ASVe, 1741a), causing great concern
and additional damage in the western part of Cephalonia (ASVat, 1743a).
1759, June 13, 38.2o N, 20.5o E, h = n, M 6.3, Argostoli (VIII)
A journal entry of a monk reported that earthquakes began on June 2nd 1759 and lasted until
June 5th (Papazachos & Papazachou, 2003). The shock was felt in Zante (Tsitselis, 1960) and
Albini et al. (1994) mention these earthquakes in the western part of Cephalonia (Fig. 5.1.4).
Tsitselis (1904) states that according to a local contemporary note "earthquakes began [in
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Cephalonia] on the June 2nd [1759 O.S.] and continued until June 5th; the one which happened
at noon destroyed many houses and the other on the 3rd caused the collapse of most houses in
the villages and in the town." A dispatch from the Venetian authorities in Cephalonia mentions:
"in the night between June 13 and 14 [N.S.], at about six hours, there was a violent earthquake,
which was followed by a series of weaker shocks ... The following morning, about 16 hours
later, there occurred a much stronger shock that produced great ruin" (ASVe, 1759a).
Figure 5.1.4. Effects of the earthquakes of June 1759 (from Albini et al., 1994).
The damage of the two shocks was concentrated in the district of Paliki and Lixouri, where
most of the houses, windmills, and churches collapsed and a few lives were lost (ASVe,
1759b). In Argostoli the shock was strongly felt but did not cause significant damage. The
severe damage of country villages is stressed by the Provveditore Generale da Mar, Francesco
Grimani, in his 12 September dispatch (ASVe, 1759c). The main shock was felt strongly in
Zante (AGP, 1628-1807). There is no evidence that the earthquake was felt at Arta and Patras
(ASVe, 1728-1794; ASVe, 1712-1764). Strong aftershocks continued to be felt in Cephalonia
until June 5th (Tsitselis, 1904).
1766, July 24, 38.1o N, 20.4o E, h = n, M 7.0, Cephalonia (IX)
The violent shock of 1766 occurred at 5 am, followed by three more earthquakes on the
same day (Papazachos & Papazachou, 2003). Houses, churches, and monasteries collapsed, no
bell towers remained standing and 20 people were killed. Sulfur smell covered the island. Many
inhabitants moved to Moria and others stayed outdors all summer. On October 18th, about 3
months after the mainshock, a resident of Cephalonia wrote that the earth had not quieted down.
(Perrey, 1848; Barbiani & Barbiani, 1864; Katrames, 1880; Partsch, 1890; Tsitselis, 1960).
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Albini et al. (1994) state the occurrence date as July 22nd (N.S.) and reports the a destructive
earthquake in Cephalonia, preceded by a foreshock before dawn, had the main shock occurred
one hour after sunrise on 11 July 1766 (O.S.) lasting, with intermissions, three minutes. The
earthquake was followed by three other shocks in the same day. The western part of Cephalonia
suffered the most (Albini et al., 1994). A manuscript note from Michalitzata (Vergotis, 1867)
says that most of the houses in t Paliki were destroyed and those left standing were damaged.
Damage extended to Assos (ASVe, 1766e, f), Lixouri (ASVe, 1766b) and Argostoli, where,
among others, the Latin church of San Nicolò in Argostoli (ASVe, 1766d) and a number of
manor houses were ruined (Fig. 5.1.5). An estimated 20 people were killed in the island.
Figure. 5.1.5. Localities damaged by the whirlwind of 31 May [square] and by the earthquake of July 1766 [circle] (from Albini et al., 1994).
1767, July 22, 04: 38.3o N, 20.4o E, h = n, M 7.2, Cephalonia (X, Lixouri)
The 1767 event is reported as the strongest felt earthquake up to that time in Cephalonia
(Barbiani & Barbiani, 1864; Stamatelos, 1870; Katramis, 1880; Partsch, 1887; Maragakis,
1977; Kavasakales & Polymenakos, 1988; and Newspaper Neologos Patron dated 29.09.1953.
Based on the available information, Papazachos & Papazachou (2003) mention that felt seismic
activity started a month before the mainshock and intensified on July 11th. The earthquake
occurred in the early morning of July 22nd and destroyed most of the Cephalonia houses and
damaged many of the remaining ones. In Lixouri, all houses collapsed and 50 people were
killed. Another event occurred on July 24th, with same intensity as the first, but smaller
duration, resulting in collapse of damaged stone houses and churches.
Similar to the 2014 events, the villages on the west of Paliki peninsula suffered the most
severe damage with evidence of landslides, liquefaction, and large open cracks on the ground
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surface (one reaching 100 m in length and 1 m in width). A total of 2,642 houses were destroyed
and 2,946 were damaged. The total death toll was 253 in the whole island. In the monastery of
Bardianon (south of Lixouri) all buildings collapsed up to their foundations. A new wooden
church was built in replacement, while the overall damage was restored in 1770.
1862, March 14, 38.3o N, 20.4o E, h = n, M 6.5, Argostoli (IX)
Based on information by Barbiani (1864), Sieberg (1932), and Montandon (1953),
Papazachos & Papazachou (2003) mentioned that the violent shock destroyed Argostoli and
caused some damage in Lixouri. Some damage was also observed in Corfu but no damage was
observed in Zante, where another shock was felt on March 26th.
1867, February 4, 04:19, 38.39o N, 20.52o E, h = n, M 7.4, Cephalonia (X, Lixouri)
According to Papazachos & Papazachou (2003), large destructions occurred in villages
located in the western part of Paliki peninsula, where Lixouri is located and where only two
houses were saved. The villages Katoe, Anoe, Nisochori, Thynnios, Dellaportata, Kouraklata,
Metaxata, Kaligata, Schoenias, Aghia Thecla, Poriorata, and Baroskes were entirely destroyed.
A total of 2,612 houses were destroyed, 2,946 suffered damage and at least 224 people were
killed. Withdraw of the sea was observed before and after the earthquake. A minor sea wave
was observed. Fissures of the ground were observed and the widest of these crossed the
pavement of Lixouri, where all houses collapsed. Phenomena of liquefaction and rock falls
were observed, similar to the 2014 events.
In Argostoli, houses located on the seaside, suffered damage and four of them were
destroyed entirely. The earthquake caused much smaller damage in Ithaca and in Lefkada,
where two villages were destroyed. Negligible was the damage in Zante (Zakynthos), Corfu,
and in the neighboring mainland. The felt area was elliptic in shape, defined by Epidamnos
(Dyrrachio), Olympus of Thessaly, Pagases, West Euboea, Kea, Maleas, Tarado, and Otrado
of Italy. Just before the earthquake, a horse in Argostoli cut its bonds, got out from the stable
and started to run. The earthquake was preceded in the night by other shocks. Aftershocks
continued daily for months until the end of April, some felt as far as Athens (Schmidt, 1867b;
Vergotes, 1867; Spanopoulos, 1867; Ioseftypaldos, 1868; Alisandratos, 1962).
1912, January 24, 16:22, 38.11o N, 20.67o E, h=n, M 6.8, Cephalonia (X, Asprogerakas)
The 1912 earthquake partly destroyed Cephalonia and Zante (Zakynthos) according to
Papazachos & Papazachou (2003). Large parts of the Cephalonia villages of Asprogerakas,
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Poros (Pronos), Scala, and Chionata (Elios) and some villages in the northern part of Zante
were destroyed. In Poros (very near Asprogerakas), 8 people were killed and 40 were injured.
In Argostoli, two fissures, 5 to 7 cm wide and 70 to 110 m long, were observed in the dock,
while in the cobbled street of Zante observed fissures were about 20 m in length. Some damage
was also observed in Ithaca. In Gastoune, 10 houses had major cracks and in the village of
Roviata a house collapsed. The earthquake shook almost all of Greece and was very strongly
felt in Lefkada, Messologhi, Agrinio, and Kyparissia. The aftershocks continued up to April
and some of these were strong enough to cause additional damage in the already damaged
houses. (AOA, 1916; Eginitis, 1916a). The largest aftershock occurred three hours after the
mainshock (h= 19:52:35, M5.9). Isoseismals are cited by Goulandris (1916), in the atlas of
UNESCO (Shebalin et al., 1974b) and by Papazachos et al. (1997b).
1915, January 27, 01:09:56, 38.36o N, 20.60o E, h = n, M 6.6, Ithaca (IX, Exogi)
Information on the sequence of 1915 events were compiled by Papazachos & Papazachou
(2003), according to which the villages of Exogi and Kolieri many houses collapsed and the
remaining were seriously damaged. The neighboring villages also suffered serious damage.
Many small fissures, 3 to 5-m long with EW or NW-SE direction were observed in Ithaca.
Ground subsidence of up to 60 cm was observed in several locations. The earthquake was
violently felt all Ionian islands, western Greece and northwest Peloponnese. The earthquake
was felt as two shocks in the town of Kyparissia, while reports of preceding sounds were
reported in the town of Magoulades at the island of Corfu. The felt area reached Avlona and
the Italian coast (Lecce, Otranto, Alessano) (Eginitis, 1916b; Michailovic, 1951). It was
followed by aftershocks, the largest of which occurred on February 20th (h = 08:13:24, M5.0)
and was strongly felt in Lefkada. Isoseismals of the earthquake are cited in the atlas of the
Geophysical Laboratory of the AUTH (Papazachos et al., 1982, 1997b).
1915, August 7, 15:04:03, 38.50o N, 20.62o E, h = n, M 6.7, Ithaca (IX)
During the 1915 earthquake, in the Cephalonia villages of Exogi, Kolieri, Platithrias,
Kolyvia, Stavros, Sami and Aghioi Saranda of Ithaca, out of 350 houses, 50 collapsed, 100
became uninhabitable and more than 100 were significantly damaged (Papazachos &
Papazachou, 2003). Cracks 2 to 15 m long and 10 cm wide with NW-SE direction were
observed on the ground surface. In the area of Platithrias ground subsidence occurred. In
Lefkada island no major damage was observed in the main town, while 4 houses of Vasiliki
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village became uninhabitable. In the same island, a large part of Aghios Petros suffered large
destruction, especially villages of Kontaraena, Eughiros, and Nydri. A part of the cape Doukato
tumbled down to the sea. Large rocks fell from the mountains of Stavrota and Vournika.
In Cephalonia, villages located in the opposite side of Lefkada suffered serious damage. In
the village of Feredinata, from the 130 houses, 30 overturned. Just before the earthquake, the
sea between Cephalonia and Lefkada was upset and two opposite large waves were formed
and directed south. In Lefkada, the earthquake was preceded by noise, which came from the
sea. In Preveza, many houses were seriously cracked, while small damage was reported in the
island of Paxoi. The felt area was spread in great distances, reaching from Corfu, Ioannena,
Karditsa, Larisa, Volos, Lamia, Trikala, and Kyparissia to the coast of Hepiros and Albania
(Avlona), as well as in the Italian coast (Lecce, Otranto, Dica, Alessanso, Callipole, Tarisano)
(AOA, 1926; Michailovic, 1951). The mainshock was followed by a large number of
aftershocks, the largest of which occurred on August 11th (h= 09:10, M6.4) and caused
considerable damage. Isoseismals of the earthquake are cited in the atlas of the Geophysical
Laboratory of University of Thessaloniki (Papazachos et al., 1982, 1997b).
1953, August 12, 09:23:52, 38.3o N, 20.8o E, h = n, M 7.2, Cephalonia (X+, Argostoli)
The 1953 earthquakes were a sequence of destructive shocks, the largest of which occurred
on August 12th with a surface wave magnitude Ms = 7.2 (Papazachos & Papazachou, 2003).
Many foreshocks occurred, two of which were particularly destructive. The first foreshock
occurred on August 9th (h = 07:41, Ms = 6.4) and the second on August 11th (h = 03:32, Ms =
6.8). It was followed by many aftershocks the largest of which occurred (h = 12:05, Ms = 6.3)
on the same day as the main shock. Significant damage was caused in all Ionian islands and
mainly in Cephalonia, Zante, and Ithaca, which were almost entirely totaled. Out of 33,300
houses in these islands, 27,659 collapsed, 2,780 were seriously damaged, 2,394 were slightly
damaged, and only 467 survived. 455 people were killed, 21 disappeared, and 2,412 were
injured. In the island of Lefkada, 122 houses were seriously damaged and 341 were lightly
damaged. The damage expanded in Aetolia and Elia, where 18 and 46 settlements were
damaged, respectively. In total, 60 houses of Aetolia were destroyed and 293 suffered damage,
while in Elia 50 houses were destroyed and 1546 suffered damage. Clear traces of upward
motion was observed at several locations in the east and south coast of Cephalonia. The largest
intensities (IX-X) were observed in the Cephalonia towns of Argostoli, Lixouri, Valsamata,
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Asprogerakas, Havdata, and Aghia Efthimia. In Zante intensities were between (IX) and (IX+).
The mainshock was also felt in lower Italy (BGINOA, 1953; Galanopoulos, 1955). Isoseismals
of the mainshock and largest foreshocks are cited in Papazachos et al. (1982). Photos from the
1953 earthquakes are shown on Figs 5.1.6 to 5.1.10.
Figure. 5.1.6. Damage to Argostoli waterfront after the 1953 earthquakes (kefalonitikanea.gr, 2013).
Figure. 5.1.7. Massive collapse of Cephalonia housing stock following the 1953 earthquakes (web).
Figure. 5.1.8. Temporary tents used to house thousands of homeless and serve as hospitals for the injured under very difficult conditions after the 1953 earthquakes (ionian-island.co.uk/greece).
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Figure. 5.1.9. Damage to the Argostoli obelisk monument “Kolona” (GPS coordinates 38°10'26.25"N, 20°29'45.59"E) following the 1953 earthquakes (ionian-island.co.uk/greece). The monument was rebuilt. Its upper drum toppled after the 2nd event of 2014 (see Bridges Section 8.5 of this report).
Figure. 5.1.10. Photograph of mother and child at Argostoli port following the 1953 earthquakes (t53vorini-gr.blogspot.com).
1972, September 17, 14:07, 38.21o N, 20.31o E, h=n, M6.3, Cephalonia (VII, Chavriata)
The 1972 M 6.3 earthquake caused damage in the southwest part of Cephalonia
(Papazachos & Papazachou, 2003). 108 old houses had to be demolished and 57 buildings and
two bridges had significant cracks. No life was lost and only one person was injured. The most
significant damage and overall intensities were observed in the Cephalonia towns of Chavriata
(VII), Damoulianata, Kouvalata, Aghia Thekla, Matzouvinata, Skinea, and Delaportata (VI+)
(BGINOA, 1972). Isoseismals are cited in the Atlas of the Geophysical Laboratory of the
University of Thessaloniki (Papazachos et al., 1982, 1997b). Foreshocks preceded, the largest
of which occurred on August 14th (h = 19:22, M4.4) and a large number of aftershocks
followed, the largest of which occurred on October 30th (h = 14:32, M5.4).
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1983, January 17, 12:41:31, 38.1o N, 20.2o E, h = n, M 7.0, Cephalonia (VI, Argostoli)
The 1983 large M 7.0 earthquake had epicenter in the Ionian sea area southwest of
Cephalonia (Papazachos & Papazachou, 2003), causing generally small damage (Intensity VI)
in the island. The largest aftershock occurred on March 23rd (h=23:51, M 6.4) and caused larger
damage in Cephalonia (VI in Aghia Thekla) due to the proximity of the epicenter to populated
areas. The recorded Peak horizontal Ground Acceleration (PGA) values were 173 and 142
cm/sec2 (0.17 and 0.14 g) from the main event in two lateral directions, and 180 and 219
cm/sec2 (0.18 and 0.22 g) from the March 23rd aftershock (Theodulidis et al., 2004).
Isoseismals of the January 17th event are given by Papazachos et al. (1997). Comparisons of
the recorded ground motions from the 1983 earthquake are presented in Chapter 7 of this report.
5.2 Seismic Hazard Evaluation {in progress} Future versions of this report will present comparisons of observed and theoretically
estimated intensity distributions from historical records to regional probabilistic seismic hazard
studies.
CHAPTER 6
Geology and Seismotectonics
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Report Version 1
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐1
6.1 Geology and Geomorphology INTRODUCTION
The geological structure of Cephalonia Island is characterized by mostly carbonate rocks
belonging to either the Pre-Apulian or Ionian geotectonic zones. An elongated post-Miocene
basin, the remnants of which cover about half of the Paliki peninsula, interrupts the continuity
of the bedrock formations. The geomorphology is characterized by Northwest-Southeast (NW-
SE) trending morphological structures (ridges, valley, shorelines, etc.), attributed to the
structural fabric of the island.
GEOLOGY
Cephalonia is located at the westernmost part of Greece. Geologically, the island is within
the outermost edge of the External Hellenides zone (Fig. 6.1.1), which is an active part of the
ongoing subduction of the African plate under the Eurasian one (Fig. 6.2.1).
Figure 6.1.1. Geological zones of Greece including the External Hellenides zone which includes the island of Cephalonia (modified from Himmerkus et al., 2007)
The Hellenides zone consist the southernmost part of the Alpine mountain chain in Europe.
The geotectonic evolution of this zone reflects the conditions associated with the closure of
Tethys Ocean, a process still in progress to date.
Cephalonia
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐2
Figure 6.1.2. Simplified active plate tectonic activity. Black arrows indicate plate motions relative to Eurasia and small white arrows show direction of internal extension over the greater Aegean area (modified from Papazachos and Papazachou, 2003; also in GEER Report No. 013).
The formation of the Hellenides zone is mostly a result of the Alpine orogeny with the
regional rock classified as pre-Alpine, Alpine and post Alpine ones, predating, concurrent and
postdating the main orogenic phase respectively. The Hellenides zone of a general NNW-SSE
trend (Fig. 6.1.1), divided into several geotectonic subzones, depending on the bedrock’s age
and formation history (Figs. 6.1.3, 6.1.4). In general, the geotectonic zones in Greece can be
grouped into three distinct groups:
Hellenic Hinterland: Paleozoic and Mesozoic crystalline rocks in NE Greece, representing the pre-Alpine bedrock. They have being intruded by granitoid Tertiary incursions and exhumed through a core complex mechanism.
Internal Hellenides: Rocks with a wide range of age and origin that are considered to represent the remnants of Neotethys and Paleotethys Ocenas, i.e., ophiolites and associated sedimentary rocks, together with old crustal fragments forming the Pelagonian continental block. They are also intruded locally by granitic volumes.
External Hellenides: In the outermost rocks of the Hellenic Arc, this group is the youngest sequence of Alpine rocks, exclusively of marine sedimentary nature. The age of the rocks typically start at Triassic and end with the deposition of flysch, whose age is gradually younger towards the West, indicating a gradual uplift.
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Figure 6.1.3. Generalized map of geotectonic units of Greece. In general, the zones are younger moving towards West. The bedrock of Cephalonia consists of Ionian and Pre-Apulian Units (IGME, 1985)
Post-Alpine sediments overlie pre-existing Alpine and pre-Alpine rocks in basins, the most
important of which is the Meso-Hellenic Trough, a wide and long NNW-SSE molassic basin
in northern and central Greece. Many basins in Greece are f tectonic origin, being formed by
neotectonic normal faults. It has to be noted that the term “post-Alpine” refers to sediments
that have been deposited after the main paroxysmal phase of the Alpine orogeny. Since this
phase is progressively younger toward the West, as the emergence ages show, this term is also
applied in a different way in various parts of the Hellenides zone; a Miocene sediment for
example is considered as post-Alpine in central Greece, while it is one of the latest Alpine
members of the Pre-Apulian sequence in Cephalonia.
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Figure 6.1.4. Neotectonic map of Cephalonia and Ithaca islands (modified from Lekkas et al., 1996).
The bedrock of Cephalonia Island mainly consists of carbonate rocks, divided into two
units as shown in Figure 6.1.4:
1. Pre-Apulian (Paxos) unit: This rock unit covers most of the island, consisting mainly of a thick sequence of carbonates (limestone and dolomite) of Triassic to Middle Miocene age, overlain by a much thinner fine clastic sequence of marl and pelite of Middle Miocene to Lower Pliocene age.
2. Ionian unit. This unit covers part of the southeastern coastal areas of Cephalonia and the entire Ithaca Island. It also consist of carbonates of Jurassic-Cretaceous age, while their contact with the Pre-Apulian unit is defined by a frontal thrust of a general NNW-SSE direction. The lowermost part of the Ionian consists of a Triassic evaporite series that acts as “lubricant” for the thrusting.
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The regional post-Alpine deposits are the following Pliocene to Holocene sediments units:
1. Lower Pliocene – Lower Pleistocene sedimentary sequence (Pl-Pt in Fig. 6.1.4) deposited in elongated basin in NNW-SSE direction, mostly of basal conglomerate, overlied by sandstone, marl and conglomerate covering most of the Paliki peninsula.
2. Middle Pleistocene – Marine calcarenite with a basal conglomerate, forming local coastal terraces.
3. Middle Pleistocene – Talus cones and lateral scree of cemented limestone blocks.
4. Holocene sediments – Fluvial loose sand and pebbles forming alluvial fans.
Figure 6.1.5. Topographical map of Cephalonia and Ithaca Islands, showing the main thrust separating the Ionian (IU) and Pre-Apulian Units (PU). The brown-shaded area (Pl-Pt) approximately marks the area covered by post-alpine (Lower Pliocene to Holocene) sediments in Paliki peninsula (IGME, 1985).
Most of the damage from the 2014 earthquakes was observed in the Paliki peninsula,
particularly within the Lower Pleistocene sequence and on younger Holocene alluvial deposits.
It is likely that the poor mechanical properties of these sedimentary sequences may have
generated significant soil amplification effects. Liquefaction was observed almost exclusively
in Holocene sediments, while rock falls and landslides occurred mainly in steep areas of
carbonate rock slopes.
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GEOMORPHOLOGY
The geomorphology of Cephalonia Island is characterized by steep bedrock slopes,
especially along its western shoreline. Ridges are controlled by lithology and tectonics
arranged in a NNW-SSE directions, the same as the dominant strike directions of the bedrock
formations. The Paliki peninsula, the area hit hardest by the earthquake, is elongated peninsula
and connects to the rest of the island at its northernmost part.
Figure 6.1.6. Cephalonia and neighboring islands: (a) slope map and (b) slope direction map.
(a)
(b)
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FAULTING
Cephalonia is crisscrossed by faults of various directions and kind (normal, reverse and
strike-slip ones), as shown in the neotectonic map of Figure 6.1.4. A well-documented offshore
active fault known as CTF (Cephalonia Transform Fault) is in very close proximity as shown
on Figure 6.1.7.
Figure 6.1.7. Main seismotectonic properties of the Aegean and surrounding regions. The study area is indicated by a rectangle. CTF = Cephalonia Transform Fault (modified from Karakostas et al., 2004).
The Greek Database of Seismogenic Sources (Gre.Da.S.S.) team has composed the main
active fault zones in the area, presented in Figure 6.1.8. These zones are associated with known
historical and instrumentally recorded large earthquakes. Their shape, direction and rake have
been critically calculated from existing seismological and structural information. The
seismogenic source GRIS 621, as identified by the Gre.Da.S.S. team in 2009, indicates a
segment capable of generating a magnitude Mw 6.1 earthquake, similarly to the 1st event of
January 26th, 2014.
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐8
The actual seismogenic area that includes the aftershock sequence and the 2nd main event
of February 3, 2014, is also in good agreement in size with the computed one, but its location
is shifted to the east. Chatzipetros et al. (2014) argue that this is a result of the pattern of faulting
during the earthquakes, i.e., the activation of associated dextral and reverse faults, rather than
the offshore zone itself. In any case, as field observations indicate, the causative faulting
mechanism did not reach the surface.
Figure 6.1.8. Seismogenic sources (i.e., active fault zones) in Cephalonia and surrounding areas, as mapped by the Gre.Da.S.S. team (Greek Database of Seismogenic Sources, gredass.unife.it). Yellow rectangular shapes represent surface projection of fault zones, and the arrows indicate the fault rake.
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐9
SEA RECLAMATION HISTORY
According to information provided by the local community, reclamation of the sea has been
historically taking place after each large earthquake. Residents who had experienced the 1953
catastrophic earthquakes, recall that the material used for the reclamation was debris from the
ruins left from these events.
Some background information is available for Argostoli, the capital and business center of
Cephalonia since the 18th century, with a main port shown on Fig 6.1.9 at is original state. The
city was destroyed from bombings during World War II in 1943 and the subsequent 1953
earthquakes. Recovery from these destruction took decades and was ongoing until the 1980s.
Figure 6.1.9. Argostoli port in 18th century (from ionian-island.co.uk).
Figure 6.1.10. Argostoli port in 1901 (modified from Pavlidis et al., 2010).
A virtual walkthrough of Argostoli before the 1953 earthquakes has been developed by
Pavlidis et al. (2010), incorporating historic data on the urban development of Argostoli.
Coastline of 1901 is shown on Fig. 6.1.10 and a 1949 topographic map is presented on Fig.
6.1.11. Aerial photos of 1940s and 2013 are shown on Figs. 6.1.12a,b, respectively.
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐10
Figure 6.1.11. Topographic map of Argostoli in 1948 (from Pavlidis et al., 2010).
Figure 6.1.12. Argostoli aerial photos in: (a) late 1940s (Pavlidis et al., 2010), (b) 2013 (Google Earth).
(a)
(b)
GEER/EERI/ATC Cephalonia, Greece 2014 6‐Geology and Seismotectonics Report Version 1 6‐11
Based on our discussions with the local residents, the port of Lixouri was damaged in 1953
in a similar manner to that observed in 2014 (Fig. 6.1.13). The damaged seafront was
demolished and then demolished materials together with the debris from damaged houses to
extend the port area. The difference in the width of the port area is visible in Fig. 6.1.13. Further
information will be provided in future versions of this report, as data on the sea reclamation
history is under investigation by our contributors.
Figure 6.1.13. Lixouri port following the earthquakes of: (a) 1953 and (b) 2014.
6.2 Seismotectonics Currently the seismotectonic mechanisms of the Cephalonia earthquakes are still under
investigation. Specifically, there is uncertainty related to the geometry of the ruptured area that
generated the two events, including the possibility of having a pair of closely-spaced parallel
dextral strike-slip faults with a trust component that ruptured in a sequence, whose aftershocks
are difficult to separate. Additionally, since the recording instruments are located in their vast
majority on the east of the island, there is uncertainty regarding to the location of the epicenters.
Some preliminary seismological information is provided in the next Chapter 7, primarily
focused on the 1st Mw 6.1 event of 1/26/14. In this Chapter, remote sensing interferometry after
the 2nd event is provided and currently being used to clarify the questions in the seismotectonic
aspects of these earthquakes. The following issues under investigation will be addressed in the
next version of this report: (i) magnitude and depth; (ii) activated fault; (iii) space-time
distribution of relocated events; and (iv) fault plane solutions and stress-field.
(a) (b)
CHAPTER 7
Seismological and Strong
Motion Aspects
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
PGA = 0.75 g
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐1
7 Seismological and Strong Motion Aspects INTRODUCTION
This chapter presents preliminary principal seismological and strong motion aspects of
the1st mainshock event in Cephalonia that occurred on January 26th, 2014 with moment
magnitude Mw of 6.1 and with epicenter off the southwest coast of the island. Seismological
information on the 2nd Mw = 6.0 mainshock event of February 3rd, 2014, with epicenter
around the Lixouri area, will be provided in the next version of this report, with only
selected available data included in Section 2 of this Chapter. Digital data of both
mainshocks recorded by the EPPO-ITSAK and NOA-IG stations were made available to
our team and are accessible at the web links:
itsak.gr/news/news/65 (EPPO-ITSAK)
gein.noa.gr/data/kefalonia/LXRB_20140126_135543_unc.dat (1st event, NOA-IG)
gein.noa.gr/data/kefalonia/SMHA_20140126_135543_unc.dat (1st event, NOA-IG)
gein.noa.gr/data/kefalonia/ARGA_20140203_030844_unc.dat (2nd event, NOA-IG)
gein.noa.gr/data/kefalonia/SMHA_20140203_030844_unc.dat (2nd event, NOA-IG)
At present there is uncertainty as to the geometry of the ruptured area that generated the
two events, including the possibility of having a pair of closely-spaced parallel dextral
strike-slip faults with a trust component that ruptured in a sequence, whose aftershocks are
difficult to separate. Some indication of this possibility comes from the remote sensing
interferometry presented in Section 3 of this Chapter. In addition, since the seismographic
network is almost exclusively located on the east of the island, some uncertainty exists as
to the location of the epicenters. These issues will be addressed in future versions of this
report.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐2
7.1 First Main Event of January 26, 2014 On Sunday January 26, 2014, 13:55 GMT (15:55 local time) a strong earthquake with
magnitude M 6.1 (HVR) occurred at the southwestern coasts of Cephalonia, about 9 km
southwest of the Lixouri town. According to the Seismological Center of the Aristotle
University of Thessaloniki (AUTH), it was a shallow crustal event with epicenter 38.161N,
20.340E and depth 10 km (geophysics.geo.auth.gr). At 18:45 GMT (20:45 local time) a
strong aftershock with magnitude M 5.5 followed the mainshock.
Figure 7.1.1 Epicenters of 1/26/14 1st mainshock (Mw6.1, red star), aftershock (Mw5.5, yellow star) and 48-hour aftershocks (M ≥4.0) (source: Geophysical Laboratory, AUTH). Instruments: EPPO-ITSAK accelerographs (yellow squares); seismographs (pink triangles). NOA-IG accelerographs (green squares) and permanent station VLS (green triangle). Focal mechanisms (source: Columbia University) and preliminary seismic fault (by Dr. Papaioannou, ITSAK) shown in red line.
The strike slip Cephalonia Transform Fault (CTF) (Scordilis et al., 1985) was related
to the focal mechanisms of both the mainshock (13:55 GMT) and aftershock (18:45 GMT)
events. CTF is a dextral strike-slip fault with a thrust component (Papazachos and
Papazachou 1997, 2003) shown as the grey focal mechanism on Fig. 7.1.1. In the same
figure, mainshock and aftershock epicenters are shown with red and pink star, respectively.
Focal mechanisms of the two events were determined by Columbia University
(www.globalcmt.org).
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From the aftershock distribution during the first two days following the mainshock, a
fault rupture length of about 18 km was established, corresponding to a moment magnitude
Mw of 6.1. The aftershock distribution of about 48 hours after the mainshock is shown also
shown on Fig. 7.1.1.
The ground shaking was strongly felt in Cephalonia and the neighboring Ionian islands
of Ithaki, Lefkada and Zakynthos. The overall felt area, shown on the macroseismic
intensity map of Figure 7.1.2, included a large part of continental Greece, south Italy and
Albania (source: European Mediterranean Seismological Centre, EMSC; emsc-csem.org).
Figure 7.1.2. Observed macroseismic intensities of the 1st mainshock event of 1/26/14 (EMSC, 2014).
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐4
INSTRUMENTATION AND STATION NETWORK
During the past three years, EPPO-ITSAK (Institute of Engineering Seismology and
Earthquake Engineering) and NOA-IG (National Observatory of Athens Geodynamic
Institute) have installed a dense network of continuous recording broadband accelerographs
of high resolution (24bits), with absolute GPS time throughout Greece. These instruments
are supported by existing accelerographs of previous generations (12-16bits digitizers).
Recordings of the network are transferred in real time at the central computing units of the
two institutions.
On the day following the 1st event, scientific and technical staff of EPPO-ITSAK
installed additional accelerographs and seismographs in Cephalonia to record potential
future earthquakes on natural and built environment (EPPO-ITSAK, 2014).
Collaboratively, additional instruments were installed by the Geotechnical Engineering
Laboratory of UPATRAS. The permanent strong motion stations (digital instruments) on
the Cephalonia and Ithaki Regional Unity were installed and run by EPPO-ITSAK, NOA-
IG and UPATRAS. The geographical distribution of the accelerographs of the three
institutes are shown on Fig. 7.1.3.
Figure 7.1.3. Permanent accelerographic stations installed by EPPO-ITSAK, NOA-IG and UPATRAS at epicentral distances up to 200 km. The epicenter of the 1st event is shown in red.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐5
Most of these instruments are of continuous mode that provide information on the
seismic source properties of the mainshock and its aftershocks. This continuous information
is significant as it can be used for ground motion prediction in the near field and site effects
studies. Some of the instruments are of trigger mode, but their resolutions are very high
providing high quality strong motion data.
Table 7.1.1 lists the installed and triggered accelerographic instruments within an
epicentral distance of 200 km as a result of the 1st mainshock event, including station
location, geographical coordinates, and owner (EPPO-ITSAK, NOA-IG, UPATRAS). The
epicentral and hypocentral distances, orientation of N/L, E/T and Z/V components (azimuth
from N) and corresponding PGA values.
STRONG GROUND MOTION RECORDINGS
In less than 10 minutes after the earthquake, preliminary shakemaps became publically
available with distribution of instrumental intensity, Peak Ground Acceleration (PGA) and
Velocity (PGV) (portal.ingeoclouds.eu/sitools/client-user/Shakemaps/project-index.html).
Figure 7.1.4. Shakemaps for the 1st mainshock event of Mw 6.1 in Cephalonia.
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STATION ORGANIZ LAT LON EPIC. HYPC. AZIM PGA AZIM PGA AZIM PGA
LOCATION OWNER (deg) (deg) D (km) D (km) N_L N_L E_T E_T Z Z
Aigio - Gen. Nosokomeio
AIG2 38.242 22.072 152 153 0o 2.34 90
o 2.39 Z-V 1.47
Akrata AKR1 38.154 22.313 173 173 0o 2.21 90
o 2.68 Z-V 1.41
Arxaia Olympia
AOL1 37.643 21.625 127 128 0o 4.36 90
o 6.38 Z-V 3.02
Argostoli ARG2 38.178 20.488 13 22 0o 349 90
o 424 Z-V 324
Vasilikades Cephallonia
VSK1 38.412 20.562 34 39 0o 95.0 90o 79.6 Z-V 55.1
Arta ART2 39.148 20.994 124 125 0o 3.46 90
o 4.24 Z-V 3.24
Astakos AST1 38.542 21.09 78 80 0o 15.44 90
o 25.54 Z-V 20.0
Ithaki ITC1 38.365 20.716 40 44 0o 56.54 90
o 60.44 Z-V 37.6
Ioannina IOA2 39.664 20.852 173 174 0o 3.58 90
o 4.47 Z-V 2.90
Ioannina IOA3 39.684 20.838 175 176 0o 3.62 90o 5.13 Z-V 1.85
Kato Axaia KAC1 38.138 21.548 106 107 0o 11.24 90
o 15.36 Z-V 5.52
Kalamata KAL3 37.025 22.103 200 201 0o 2.42 90
o 2.30 Z-V 1.19
Karditsa KAR2 39.366 21.92 192 193 0o 4.33 90
o 4.60 Z-V 1.19
Kalavryta KLV1 38.033 22.108 155 156 0o 3.75 90
o 4.90 Z-V 1.79
Kerkyra KRK1 39.618 19.916 166 167 0o 8.33 90
o 6.05 Z-V 2.84
Kyparisia KYP2 37.25 21.667 154 156 0o 1.92 90o 2.54 Z-V 0.97
Lefkada LEF2 38.83 20.708 81 83 0o 26.46 90
o 23.18 Z-V 16.2
Megalopolis MGP1 37.402 22.138 179 180 0o 2.85 90
o 3.08 Z-V 1.64
Mesologi MSL1 38.373 21.424 98 99 0o 26.53 90
o 17.75 Z-V 6.36
Patra - Nosk. Ag. Andreas
PAT4 38.234 21.748 123 125 0o 7.53 90
o 11.00 Z-V 5.44
Rio - Geniko Nosokomeio
PAT5 38.296 21.795 128 129 0o 5.50 90
o 5.41 Z-V 3.38
Petalidi PET1 36.964 21.926 193 194 0o 2.55 90o 2.04 Z-V 0.79
Preveza PRE2 38.958 20.755 96 97 0o 15.78 90
o 16.10 Z-V 7.18
Pylos PYL1 36.914 21.695 183 184 0o 0.48 90
o 0.84 Z-V 0.40
Pyrgos PYR2 37.667 21.451 112 113 0o 5.55 90
o 5.15 Z-V 3.13
Vasiliki Lefkadas
VAS2 38.63 20.608 57 60 0o 80.01 90
o 86.17 Z-V 61.4
OTE Zakynthou
ZAK2 37.788 20.9 64 67 0o 49.39 90o 49.31 Z-V 19.6
Reginne RGG1 38.719 22.709 215 216 0o 3.28 90
o 2.85 Z-V 2.30
EPPO ITSAK
CODE
Table 7.1.1. Accelerographic stations and ground motion parameters within epicentral distances of 200 km from 1st event (1/26/14, Mw6.1). Station location, code, owner, geographical coordinates, epicentral and hypocentral distances, azimuth and PGA (cm/s2) for N/L, E/T, Z/V components.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐7
Lefkada LEF1 38.826 20.702 80 82 70o 32.08 250
o 40.66 Z-V 22.1
Vartholomio Var2 37.864 21.208 83 85 270o 18.51 0
o 13.44 Z-V 7.12
Lixouri Town Hall
LXRB 38.201 20.437 10 20 180o 561.60 270
o 425.00 Z-V 562
Sami Town Hall
SMHA 38.251 20.648 29 34 220o 269.16 310
o 238.67 Z-V 183
Volimes VLMS 37.877 20.663 42 46 0o 51.48 90
o 99.50 Z-V 30.0
Meganissi Town Hall
MGNA 38.656 20.791 68 70 340o 27.04 70
o 28.84 Z-V 6.06
Lefkada OTE
LEFA 38.833 20.704 81 83 140o 54.07 230
o 39.73 Z-V 23.0
Lechaina Town Hall
LCHA 37.937 21.264 85 86 0o 18.99 90
o 19.58 Z-V 7.14
Rio Town Hall
RIOA 38.296 21.791 128 129 100o 5.20 190
o 5.93 Z-V 3.37
Arta Town Hall
ARTB 39.157 20.979 124 125 200o 8.08 290
o 9.49 Z-V 4.14
Parga Town Hall
PRGA 39.286 20.402 125 127 240o 23.79 330
o 26.53 Z-V 3.97
Zacharo Town Hall
ZARA 37.487 21.649 137 138 150o 3.77 240
o 4.09 Z-V 2.16
Ioannina JANA 39.656 20.849 172 173 0o 2.22 90
o 3.86 Z-V 1.76
Ithomi ITMA 37.179 21.925 177 178 0o 1.13 90
o 1.34 Z-V 0.78
Kassiopi Town Hall
KASA 39.746 19.935 180 181 310o 2.22 40
o 2.66 Z-V 1.42
Delfoi Town Hall
DLFA 38.478 22.496 191 192 230o 1.09 320
o 0.96 Z-V 0.64
Metsovo Town Hall
MTVA 39.77 21.183 193 194 200o 2.64 290
o 3.15 Z-V 1.85
Trikala Town Hall
TRKA 39.553 21.766 198 199 110o 2.99 200
o 3.88 Z-V 1.82
Sofdes Town Hall
SOFA 39.337 22.097 201 202 320o 5.81 50
o 5.88 Z-V 2.34
Kiato Town Hall
KIAA 38.014 22.75 212 212 40o 3.59 130
o 3.80 Z-V 2.05
VA-1 38.233 21.74 123 124 350o 10.10 80
o 10.60 Z-V 5.40
UP-1 38.269 21.748 124 125 0o 7.31 90
o 6.54 Z-V 3.96
UP-2 38.259 21.767 125 126 0o 8.71 90
o 9.26 Z-V 6.20
UP-3 38.249 21.748 123 125 0o 6.75 90
o 9.45 Z-V 3.43
UP-4 38.221 21.721 121 122 0o 16.29 90
o 17.17 Z-V 5.52
UP-5 38.22 21.743 123 124 0o 6.99 90
o 7.79 Z-V 3.72
UP-6 38.214 21.761 124 126 0o 5.26 90
o 6.02 Z-V 2.34
UP-7 38.249 21.735 122 124 0o 12.46 90
o 11.87 Z-V 5.25
UP-8 38.235 21.747 123 125 0o 8.55 90
o 11.18 Z-V 5.88
City of Patras
UPATRAS
NOA-IG
EPPO ITSAK
STATION ORGANIZ LAT LON EPIC. HYPC. AZIM PGA AZIM PGA AZIM PGA
LOCATION OWNER (deg) (deg) D (km) D (km) N_L N_L E_T E_T Z ZCODE
Table 7.1.1. (continued)
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐8
Strong ground motion preliminary reports were quickly published on the web
(itsak.gr/news). Acceleration time histories and corresponding response spectra for 5%
structural damping are presented on Figs 7.1.5 to 7.1.7. Calculations were made with SMA
(Kinemetrics, 1999) and ART (Guralp Systems, 2009) and ViewWare for accelerograms
processing (Kashima, 2005). Some key observations are discussed in this section and
summarized in Table 7.1.2.
Table 7.1.2. Highest PGA values and their components recorded during the 1st event at stations ARG2, VSK1, LXRB, SMHA at epicentral distances of 13, 34, 10, 29 km, respectively.
Argostoli Recording (ARG2): The highest PGA amplitude recorded was 424 cm/s2
(0.43 g) in the horizontal E direction. High SA values exceeding 1,000 cm/s2 (1 g), were
generated for short periods of T < 0.3 s. In addition, relatively high SA values greater than
>500 cm/s2 (0.51 g) for periods up to 0.7 s were apparent in the NS component (Fig. 7.1.5).
Vasilikades Recording (VSK1): The SA values from the VSK1 station were up to four
times lower than those of ARG2 as was the highest PGA at 0.1 g. The overall spectral shape
was also different particularly for structural periods T > 0.5 s. The strong ground motion
bracketed duration, for ground accelerations > 0.1 g, was about 9 s in both horizontal
components and 6 s in the vertical (Fig. 7.1.6).
Lixouri Town Hall Recording (LXRB): At LXRB station, the highest PGA recorded was
562 cm/s2 (0.57 g) in the vertical direction, perhaps due to close proximity to the epicenter,
compatible with observed roof-tiles displacements discussed in Chapter 11. SA reached
2,000 cm/s2 (~ 2 g) for short periods between 0.05 and 0.08 s in the vertical direction. For
the horizontal components, PGA amplitudes were 531 and 425 cm/s2 (0.54 and 0.43 g),
while SAs reached 1,300 cm/s2 (1.3 g) for periods between 0.5 and 1.0 s (Figs. 7.1.7, 8).
Sami Town Hall Recording (SMHA): Located 20 km from the epicenter, the SMHA
station, recorded PGAs up to 239, 269, 183 cm/s2 (0.24, 0.27, 0.17g) for L,T,Z components,
respectively. The maximum SA was calculated at 1,000 cm/s2 (~ 1g) at 0.3 s in the lateral
direction and 600 cm/s2 (0.61 g) at 0.1 s in the vertical direction (Figs. 7.1.9 and 7.1.10).
STATION ORGANIZATION EPICENTAL max
LOCATION OWNER DISTANCE (km) PGA (g)
Argostoli ARG2 EPPO-ITSAK 13 0.43 E(T)
Vasilikades VSK1 EPPO-ITSAK 34 0.10 N(L)
Lixouri Town Hall LXRB NOA-IG 10 0.57 V(Z)
Sami Town Hall SMHA NOA-IG 29 0.27 N(L)
CODE COMPONENT
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐9
Figure 7.1.5. Acceleration, velocity and displacement time histories recorded at Argostoli (ARG2) station (top). Corresponding response spectra of pseudovelocity PSV and acceleration SA (bottom) for the 1st mainshock event of 1/26/14, 13:55 GMT (Mw6.1). Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐10
Figure 7.1.6. Acceleration, velocity and displacement time histories recorded at Vasilikades (VSK1) station (top). Corresponding response spectra of pseudovelocity PSV and acceleration SA (bottom) for the 1st mainshock event of 1/26/14, 13:55 GMT (Mw6.1). Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐11
Figure 7.1.7. Lixouri (LXRB) station recordings of acceleration (left), velocity (middle) and displacement (right) time histories for the 1st mainshock event of 1/26/14, 13:55 GMT (Mw6.1). Figure 7.1.8. Acceleration response spectra from the Lixouri (LXRB) station recordings of Figure 7.1.7 (1st mainshock event of 1/26/14, 13:55 GMT, Mw6.1). Structural damping 5%.
Time t : s
A : mm/s2 V : mm/s D : mm
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐12
Figure 7.1.9. Sami Town Hall (SMHA) station recordings of acceleration (left), velocity (middle) and displacement (right) time histories for the 1st mainshock event of 1/26/14, 13:55 GMT (Mw6.1).
Figure 7.1.10. Acceleration response spectra from the Sami Town Hall (SMHA) station recordings of Figure 7.1.9 (1st mainshock event of 1/26/14, 13:55 GMT, Mw6.1). Structural damping 5%.
Time t : s
A : mm/s2 V : mm/s D : mm
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐13
GROUND MOTION ATTENUTATION
Figure 7.1.11 presents plots of the horizontal Peak Ground Acceleration (PGA) of all
strong motion recordings of the Greek stations as function of the stations distance from the
epicenter of the 1st mainshock. In this version, all recorded PGA values are plotted for both
horizontal components, regardless of the site conditions of the accelerographic stations. An
update will follow in the next version when more details on the site conditions are available.
The recorded PGA values are compared to calculated PGAs from the Ground Motion
Predictive Equation (GMPE) proposed by Skarlatoudis et al. (2003) for Greece. Median
and plus one standard deviation (σ) of the GMPE are shown in the same with blue lines.
Figure 7.1.11. Peak Ground Acceleration (PGA) of the two horizontal components recorded by all stations in the Greek network from the 1st event versus epicentral distance. Blue lines show median and +one standard deviation (σ) of Ground Motion Predictive Equation (GMPE) for Greece by Skarlatoudis et al., (2003). Red circles are L(N) components and open circles are T(E) components.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐14
COMPARISON TO 1983 CEPHALONIA EARTHQUAKE
The most recent large event on the causative fault occurred on January 17th, 1983 with
magnitude M 7.0. Despite its large magnitude, this event caused a macroseismic intensity
IMM = VI according the NOA Bulletin of Geodynamic Institute. A PGA of 0.17 g was
recorded at an epicentral distance of 35 km from Argostoli (Theodoulidis et al., 2004). At
the time, there was only a single recording instrument on the island.
Fig. 7.1.12 compares Spectral Accelerations (SA) recorded at that ground surface at
Argostoli from the 1st event of 1/26/14 (Mw6.1) and the single record of 1/17/1983 (M 7.0).
For periods shorter than 1.2 s, the 2014 SA values are higher than the corresponding 1983
SA values by a factor of 2 to 3. This difference could be attributed to the shorter hypocenter-
to-station distance of the 2014 event.
Figure 7.1.12. Acceleration response spectra of horizontal components of the 1st event of 1/26/14 (Mw 6.1) at the Argostoli station (in red) and the single record of 1/17/1983 (M 7.0) at a station located 35 km from Argostoli (in blue). Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐15
7.2 Second Main Event of February 3, 2014 Seismological data and details of the 2nd mainshock event of February 3rd, 2014 (03:07
GMT) with Mw = 6.0 and epicenter around the Lixouri area, will follow in the next version.
In this version, Figures 7.2.1 through 7.2.3 (compiled by Prof. Pelekis, ASPETE)
present acceleration time histories and corresponding response spectra and horizontal-to-
vertical spectral ratios from recordings of the 2nd event by the UPATRAS Geotechnical
Engineering Laboratory stations in Argostoli Port (38.180N, 20.490E), Fokata town
(38.127N, 20.527E), and Cephalonia International Airport (38.119N, 20.506E).
Additional information from the EPPO-ITSAK recordings of the 2nd event are presented
in the Site Effects section of the following Chapter.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐16
Figure 7.2.1. Acceleration time histories in the two horizontal (E-W, N-S) and vertical directions (Z) (top) and corresponding acceleration response spectra SA (bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by the UPATRAS Argostoli Port (38.180N, 20.490E) station during the 2nd mainshock event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof. Pelekis of ASPETE. Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐17
Figure 7.2.2. Acceleration time histories in the two horizontal (E-W, N-S) and vertical directions (Z) (top) and corresponding acceleration response spectra SA (bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by the UPATRAS Fokata (38.127N, 20.527E) station during the 2nd mainshock event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof. Pelekis of ASPETE. Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐18
Figure 7.2.3. Acceleration time histories in the two horizontal (E-W, N-S) and vertical directions (Z) (top) and corresponding acceleration response spectra SA (bottom left) and SA Horizontal to Vertical ratios of (bottom right) recorded by the UPATRAS Airport (38.119N, 20.506E) station during the 2nd mainshock event of 2/3/14, 03:07 GMT (Mw6.0). Plots compiled by Prof. Pelekis of ASPETE. Structural damping = 5%.
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐19
7.3 Remote Sensing Interferometry
The German satellite TerraSAR runs every eleven days over every area of the Earth at
a distance of 700 km and can capture ground surface deformations using high resolution
SAR Interferometry. When the 1st event took place on January 28th, 2014, TerraSAR was
on its way from the South to the North Pole. Professor Parcharidis of the Geography
Department of Harokopion University in Athens immediately notified the authorities and
requested that an urgent signal is sent to the satellite for a panoramic picture of the island.
Figure 7.3.1. Study area captured by the German satellite TerraSAR after the 2nd event of 2/3/14.
Indeed, TerraSAR captured the ground surface deformation at Cephalonia Island during
the period between January 28 and February 8, a period which included the 2nd event on
February 3rd, 2014. The study area is shown in Figure 7.3.1 (Parcharidis, 2014). The data
collected include an interferometric pair of SAR images acquired by the German
TerraSAR-X (TSX): two repeat observations dated January 28 time 16:23:21 UTC and
February 8 time 16:23:21 UTC, in fine-resolution single-polarization strip map mode
ascending, strip_003R with an incidence angle range of 19°-23° at HH polarization. The
TSX interferogram captured only the 2nd earthquake event of February 3rd. The resulting
data was used to produce an interferogram using the GAMMA software.
The data were analyzed by the Geography Department of Harokopion University
(HUA). Specifically, repeat-pass Interferometry was applied and the topographic phase was
removed using a high resolution (~ 5 m) Digital Elevation Model (DEM) derived from
airborne photogrammetry, with vertical accuracy better than 5 m. The flattened
interferograms were filtered using an adaptive noise filter with a small window size and
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐20
unwrapped by means of Minimum Cost Flow (MCF) algorithm using the qualitative
coherence (above 0.3) as a weight for the MCF solution. A baseline refinement was applied
for removing residual phase ramps.
Figure 7.3.2. Interferogram from ground surface deformation measurements between January 28th and February 8th (modified from Parcharidis, 2014).
The TSX data are in the strip map high resolution mode allowing us to measure wide
areas with a high spatial resolution of ~3 m. HUA produced an interferogram spanning
eleven days from January 28 until February 8, 2014 (perpendicular baseline 108 m),
sampling the co-seismic ground displacements of the February 3rd event in the ascending
geometry. The multi-look factor applied to the interferogram is 5×5 m2, which corresponds
GEER/EERI/ATC Cephalonia, Greece 2014 7‐Seismological and Ground Motions Report Version 1 7‐21
to pixels of ~15×15 m2 on the ground (Fig. 7.3.2). Note that the western most part of the
Paliki peninsula area is not covered by the TerraSAR-X stripmap image product used for
this study, that has a scene size 30 km width × 50 km length.
The interferogram exhibits a maximum motion of approximately 11 cm in the satellite
Line of Sight (LoS) towards the satellite sensor, in the center-south of Paliki peninsula
showing max deformation areas and a max LoS motion of about 7 cm away from the
satellite at North and East of the peninsula close to Lixouri city (Briole et al., 2014).
Figure 7.3.3. Interferometer map of Cephalonia after the 2nd event (modified from NEA, 2014).
The fault rupture was predominantly strike-slip (with some thrust component) and did
not emerge on the ground surface. From the study of satellite data it was realized that
maximum ground deformation occurred near the middle NS axis of the Paliki peninsula,
with the ground surface moving southward by a maximum of 12 cm. On the eastern coast,
Lixouri moved 6 cm in the opposite direction as did Aghios Dimitrios by 7 cm, both in the
North direction, as shown on Fig. 7.3.3 (NEA, 2014).
Most of the observed damage to rigid blocks and particularly the extensive
deformations and rotations in many cemeteries presented in great detail in Chapter 9 of this
report, took place during the 2nd event of February 3rd. These observations are consistent
with the assumption that the (blind) fault which triggered the 2nd event is located at the east
side of Paliki as shown with the bold black dashed line in Fig. 7.3.3.
CHAPTER 8
Geotechnical Observations
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Report Version 1
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8.1 Site Effects INTRODUCTION
Site effects, including both soil amplification and topography effects, are hypothesized to
have played a significant role in the unusually high ground motion amplitudes recorded during
the two main Cephalonia events of January 26th with magnitude Mw 6.1 and February 3rd with
Mw 6.0. The exceptionally large recorded ground motion amplitudes and the concentration of
earthquake-induced phenomena on both soils and structures in areas of thick young Holocene
alluvial deposits of poor mechanical soil properties are indicative of ground motion
amplification due to site effects. Moreover, the hypothesis of topographic amplification is
consistent with the presence of pronounced irregular topographic features in the immediate
vicinity of some stations. However, neither hypotheses can be verified at this point due to lack
of geophysical site characterization data and high-resolution Digital Elevation Models (DEM).
Figure 8.1.1 Strong motion stations referenced in this section (LXR1, ARG2 and CHV1) on the Cephalonia neotectonic map (modified from Lekkas et al., 1996).
Airport
Fokata
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Historically, site effects have played a significant role on losses caused by past earthquakes.
As described in Papathanassiou et al. (2005), ground failures and liquefaction-induced port
facility damages have repeatedly occurred in most of previous earthquakes. For example, the
1867 earthquake triggered liquefaction resulting in a subsidence of 1 m width and 100 m length
along the waterfront of Lixouri. At the Kouvalata village, there were observations of sand
craters and ejecta while in the village of Aghios Dimitrios, a sand crater with 1 m diameter and
0.5 m high was reported (Vergotis, 1867; Partsch, 1892). Liquefaction and lateral spreading
were major factors in the destruction caused by the 1953 earthquake sequence at the ports of
Lixouri and Argostoli (as described in Chapters 2 and 5), with similarities to the observations
documented in the 2014 events (described in Section 8.2).
STRONG GROUND MOTION RECORDING STATIONS
Strong ground motion stations referenced in this section are depicted on the neotectonic
map of Cephalonia of Fig. 8.1.1 and discussed in Chapter 7. Limited geotechnical information
was available during reconnaissance in the immediate vicinity of the stations that could verify
site effect observations and hypotheses. Therefore, discussions on site effects will mainly focus
on the recording stations of LXR1, ARG2 and CHV1 of EPPO-ITSAK in the towns of Lixouri,
Argostoli, and Chavriata. All three stations are within the same Triassic geologic zone (Fig.
8.1.1). As a result, their underlying profiles and site response characteristics may bare
similarities indicative of site amplification effects. Additional recordings became available
from UPATRAS and Prof. Pelekis of ASPETE that installed strong ground motion instruments
following the 1st event at the Argostoli Port, Fokata, and Airport (Fig. 8.1.1). The few examples
presented herein merit further studies incorporating in-situ subsurface investigations due to
their significance in advancing our understanding of site effects.
SITE AMPLIFICATION
Despite their (misleading) moderate magnitudes on the order of Mw ~ 6 that could also
indicate moderate ground motion levels, the Cephalonia events yielded exceptionally large
amplitudes of ground motion. To illustrate this fact, Figure 8.1.2 compares response spectra of
these recordings (LXR1 and CHV1) from the 2nd event with Mw = 6 and both at epicentral
distances not more than 1 to 2 km away from the intersection of the fault with the ground
surface, to those recorded by the Kobe 1995 (Mw 6.9) Takatori and the Northridge 1994 (Mw
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6.7) Rinaldi stations (Gazetas, 1996). All four records have similar magnitude-distance (M-R)
combination; yet, as shown on Fig. 8.1.2, their response spectra are quite different indicating
possible influence of local site effects. Note that the Takatori and Rinaldi records are among
the very few near-field ‘impulsive-type’ recordings (Garini et al., 2014), which are invaluable
design-level motions for structural analyses and design of critical infrastructure.
Figure 8.1.2 Response spectra (5% damping) of two of the strongest records obtained during the 2nd Cephalonia event, compared to two of the most widely referenced near-field strong motion records of Takatori and Rinaldi from the Kobe 1995 and Northridge 1994 earthquakes.
Available seismological and geological data that has been presented in preceding chapters
indicates possible forward directivity effects on the fault normal (EW) component of the LXR1
station (in Lixouri) recorded 2nd event, with a Peak Ground Acceleration (PGA) of 0.68 g (Fig.
8.1.2) . The fault parallel (NS) component of the same recording, on the other hand, was not
characterized by the same long period impulsive motion, although it had comparably large
amplitude with PGA of 0.61 g.
Comparison with World Records
0
0.5
1
1.5
2
2.5
3
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3
Τ : s
SA : g
Chavriata NS2014
Lixouri EW 2014
Takatori 000 1995
Rina ldi 228 1994
SPECTRAL ACCELE
RATIO
N SA : g
STRUCTURAL PERIOD T : s
Chavriata NS2014
Lixouri EW 2014
Takatori 000 1995
Rina ldi 228 1994
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Lixouri LXR1 Station Recordings
We examined the influence of local site effects from the LXR1 station recordings of the
2nd event using available nearby subsurface information, including: (i) a geotechnical
investigation at the nearby Lixouri port conducted shortly after the 2nd earthquake to assist with
the port repairs (Fig. 8.1.3) funded by the Ministry of Public Works, Port Division
(Geosymvouloi EPE, 2014) and (ii) a shear wave velocity, Vs , profile (Fig. 8.1.4) measured
previously in-situ by Spectral Analysis of Surface Waves (SASW) as part of a European
research project (Pelekis, 2014). The generalized soil profile based on the port investigation
consists of 5 to 20 m thick deposits of poor quality sandy silts and low plasticity clays. The
representative Vs profile of Fig. 8.1.4 has an estimated elastic fundamental frequency of around
7 Hz, or 0.14 s (Fig. 8.1.5a).
Horizontal to Vertical Spectral Ratios (HVSR) of the LXR1 recordings were calculated
based on the algorithm described by Theodulidis et al. (1996) and are shown on Figure 8.1.5b.
The HVSR showed similar amplification characteristics in both the EW and NS components.
The amplification observed through HVSR were at 1.2 Hz (0.83 s) and around 3~4 Hz
(0.33~0.25 s) for the EW and NS components, respectively. However, these frequencies are
significantly lower than the fundamental frequency of ~7 Hz (0.14 s) obtained from theoretical
linear elastic transfer function of the SASW Vs profile (Fig. 8.1.5a). The discrepancy in
fundamental frequencies indicates nonlinear soil behavior and can be also attributed to the fact
that the LXR1 station was located near the north end of the port, which according to the cross-
section in Figure 8.1.3b is characterized by shallow sediments. The SASW Vs profile used to
derive the transfer function was obtained at the south end, where the same cross section reveals
layers of low plasticity clay approximately 10 m thicker than the north end. The presence of
thicker low plasticity clay layer might be shifting the fundamental frequency of the site to lower
frequencies.
The significance of this large amplitude impulsive recording for predictions of near-field
ground motions merits further site characterization studies complemented with in-situ
measurements of dynamic soils properties and laboratory testing.
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Figure 8.1.3 Geologic cross section at the port of Lixouri, revealing the low strength alluvial deposits (CL) which may have contributed to the high recorded accelerations (Geosymvouloi EPE, 2014).
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Figure 8.1.4 Spectral Analysis of Surface Waves (SASW) testing location (top) and generalized shear wave velocity, Vs, profile (bottom). Data from Pelekis (2014).
Figure 8.1.5 (a) Elastic transfer function from rock outcrop to ground surface using the generalized Vs profile of Fig. 8.1.4, and (b) Horizontal to Vertical Spectral Ratio (HVSR) of the LXR1 recording of the 2nd event
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Argostoli ARG2 Station Recordings
The role of site amplification was also examined in the ground motions recorded at station
ARG2, whose response spectrum of E-W component is shown in Fig. 8.1.6. A shear-wave
velocity profile, obtained from the restoration study of the historical Debosset bridge
(discussed in detail in Section 8.5), was used for site characterization of the ARG2 station (Fig.
8.1.7). The comparison of the theoretical linear elastic transfer function (surface to rock
outcrop) based on the Vs profile of the site to the HVSR of ARG2 recordings from both events
revealed almost identical fundamental mode at approximately 2 Hz (0.5 s). However, the
comparison results are only indicative of nature of Argostoli due to the significantly large
distance between the ARG2 station and Debosset Bridge.
The good agreement between HVSR and linear site amplification suggests that nonlinear
response was not a dominant feature of the ground response at ARG2; in absence of dynamic
soil properties, however, this hypothesis has not yet been verified. Moreover, the difference
observed in the recordings of LXR1 and ARG2, with epicentral distances of 7 and 12 km,
respectively; indicate the influence of local site effects on recorded ground motions.
Section 7.2 presents another recording of the 2nd event main shock at the Argostoli port by
instruments that were installed by the UPatras. When compared to the response spectra of the
ARG2 motions, recorded motions from both stations have similar response in terms of
amplitude. Based on similar amplitude response recorded at both Argostoli stations, similar
subsurface conditions with minor variability might be expected between the stations.
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Figure 8.1.6. Acceleration response spectrum of E-W ground motion recording at ARG2 station of EPPO-ITSAK during the 2nd event for structural damping of 5%.
PERIOD T : s
0.0 0.5 1.0 1.5 2.0 2.5 3.0
SP
EC
TR
AL
AC
CE
LE
RA
TIO
N S
A :
g
0.0
0.2
0.4
0.6
0.8
1.0
1.2ARG2 Station (Argostoli)
E-W__ARG2
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Figure 8.1.7. Site response at station ARG2: (a) shear wave velocity Vs profile at the adjacent Debosset bridge by Rovithis et al (see Section 8.5); (b) idealized Vs profile; (c) HVSR at station ARG2 from both events (4 components); and (d) theoretical linear elastic surface-to-rock outcrop transfer function at Debosset bridge SW embankment
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3D SITE EFFECTS: TOPOGRAPHIC AMPLIFICATION COUPLED TO SITE RESPONSE
HVSR studies of the recordings at station CHV1 (at Chavriata, at an epicentral distance of
7 km) also revealed distinct peaks during the 2nd event. The geologic structure in the region
(see also Figure 8.1.1) is characterized by 50 to 80 m thick sediments (interchangeable layers
of weathered marls, limestone, and sandstone) overlying much stiffer Pre-Pliocene bedrock
(Fig. 8.1.8a). For a 70 m thick soil column of average shear wave velocity 500 m/s the
fundamental frequency would be around 1.78 Hz (0.56 s). It is therefore likely that the HVSR
peaks in Figure 8.1.8 (b) are manifestations of 1D (one-dimensional) site response.
On the other hand, the CHV1 station is located in a region with very strong topographic
relief as shown on the topographic map and ground surface topography of Figure 8.1.8 (c, d).
Thus, topographic amplification may also have contributed to the large accelerations recorded
at CHV1 with max PGA of 0.76g (see Fig. 8.1.2 and Chapter 7).
Recent studies on the relative contribution of site amplification and topography effects at
sites with similar surface and subsurface geologic features as CHV1 suggest that the
simultaneous triggering of site and topography effects (referred to as 3D site effects) can
generate accelerations much higher than what would have been predicted by mere
superposition of the effects of topography and 1D site response (Assimaki et al., 2005;
Assimaki & Jeong, 2013). Moreover, several studies have shown that for ground motions levels
above 0.5g recorded at sites with soft sediments such as CHV1, 1D nonlinear site response
frequently fails to physically explain how the soil can sustain ground motion amplitudes that
supersedes its strength in simple shear (Andrews et al., 2007).
The large accelerations at CHV1 provide a learning opportunity on 3D site effects and their
complex mechanisms of ground motion amplification. This insight in turn can lead to improved
predictions of extreme ground motions and their upper physical limits that can be applied to
improve design ground motions for critical infrastructure and critical facilities.
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Figure 8.1.8. (a, b) HVSR at station CHV1 (Chavriata), revealing consistent site response modes with the 50-80m sedimentary structure underlying the region; (c, d) topographic map and cross section across Chavriata, clearly showing irregular surface and subsurface topography that may have contributed to the large recorded ground accelerations.
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COMPARISONS WITH EUROPEAN AND USA CODE SPECTRA
The Eurocode 8 (EC-8, 2008) defines the seismic hazard at a site at the firm ground
conditions (ground type A) based on seismic zonation of the local National Authorities of each
country that uses EC-8 as their model code. The hazard is defined as a reference ground
acceleration ag on ground type A (rock with shear wave velocity Vs > 800 m/s) for an event
with approximate return period of 2,500 years, and modified for site conditions based on the
ground type. Table 8.1.1 presents the definition of ground types according to EC-8. Site factors,
S, associated with each ground type and average shear wave velocity at the top 30 m (Vs,30) are
applied to produce design spectra for the various ground types. In Greece, Cephalonia is on the
highest zoning level of the national code EAK (2000) with zoned ag of 0.36 g (Fig. 8.1.9).
EC-8 code-based acceleration spectra for Cephalonia developed for rock, and dense and soft
soil conditions are presented on Fig. 8.1.10.
Figure 8.1.9. Seismic hazard mapping of Greece according to EAK (2000) for ground type A (rock). There are three zones I, II, III with reference ground acceleration ag of 0.16, 0.24, and 0.36 g, respectively. Cephalonia belongs in Zone III with ag = 0.36 g.
Cephalonia
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Table 8.1.1 Eurocode EC-8 and ASCE7-05 site classification.
ASCE 7-05 is the basis of the International Building Code (IBC 2009), currently used as
model for most local state codes in the United States (US). The local seismicity is provided by
the national USGS seismic hazard mapping for Maximum Considered Earthquake (MCE)
hazard level and Rock B site conditions (Vs > 760 m/s). Mapping is provided for two Spectral
Acceleration (SA) parameters: Ss for short-periods (0.2 s) and (S1) for long periods (1 s). Site
factors Fa and Fv modify Ss and S1 respectively to produce MCE SA values adjusted for soil
conditions (see Table 8.1.1 for ASCE7-05 site classes).
An analogy between EC-8 and ASCE 7-05 for Cephalonia can be made by identifying a
US site in the US with the same level of reference acceleration ag of 0.36 g (or Ss = 2.5 × ag =
0.72 g). Based on the USGS seismic map of ASCE7-05, the city of Portland, Oregon has Ss =
0.72 g, and will be used for comparison. Figure 8.1.10 presents ASCE7-05 MCE response
spectra for Portland and rock, dense and soft soil conditions. When two different code spectra
are compared for Cephalonia and Portland, it appears EC-8 produces slightly higher SA values
for rock and stiff sites, and is significantly higher for soft site conditions for T < 2.3 s).
Ground Vs,30 Site Vs,30
Type (m/s) Class (m/s)
A Rock > 800 A Hard Rock > 1,500
B Deep - Very Dense 360 800 B Rock 760 1500
C Deep - Dense to Medium 180 360 C Very Dense Soil / Soft Rock 360 760
D Loose to Medium Dense < 180 D Stiff Soil 180 360
5-20 m thick E Soft Soil < 180
Vs30 same as Type C or D F Liquefiable Soil
EC-8 ASCE7-05
Description Description
E
GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnncal Observations Report Version 1 8‐14
Figure 8.1.10. Comparison of design acceleration response spectra obtained based on EC-8 and ASCE 7-05 design event for Cephalonia and Portland that are on equivalent level of seismic hazard zoning.
Figure 8.1.11 compares acceleration response spectra of three records from the 2nd event at
the stations of LXR1, CHV1, and ARG2 stations (at Lixouri, Chavriata, and Argostoli) to the
EC-8 spectra for ground types A (rock) and D (soft soil). Both components of the CHV1 record
and the EW component of the LXR1 record far exceed code-based spectra in the structural
period range of less than 1 s (CHV1) and greater than 0.8 s (LXR1). As discussed earlier in
this section, local site effects and directivity have likely contributed to these high amplification
effects that need to be confirmed with pertinent in-situ testing. The ARG2 station response
spectra are lower than the code-based spectra, which can be expected since this station is farther
away from the epicenter and is on stiffer site conditions as compared to the other two stations.
PERIOD T : s
0.0 0.5 1.0 1.5 2.0 2.5 3.0
SP
EC
TR
AL
A
CC
EL
ER
AT
ION
S
A :
g
0.0
0.5
1.0
1.5
EC - 8, Cephalonia
ASCE 7-05, Portland
Dense Soil
Soft Soil
Rock
GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnncal Observations Report Version 1 8‐15
Figure 8.1.11. Comparison of acceleration response spectra of recorded Cephalonia motions at (a) LXR1, (b) CHV1, and (c) ARG2 stations with EC-8 design spectra.
0
1
2
3
0
1
2
3
P E R I O D T : s
0.0 0.5 1.0 1.5 2.0 2.5 3.0
S P
E C
T R
A L
A
C C
E L
E R
A T
I O
N
SA
: g
0
1
2
3
EC8 Rock (Type A)
EC8 Soft Soil (Type D)
LXR1 Station (Lixouri)
CHV1 Station (Chavriata)
ARG2 Station (Argostoli)
SAmax =1.66g SAmax =1.50g
2.95g 2.76g
0.77g
1.05g
N-S__LXR1E-W__LXR1
E-W__CHV1
N-S__CHV1
N-S__ARG2
E-W__ARG2
GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnncal Observations Report Version 1 8‐16
CONCLUSIONS
Although analysis of Horizontal-to-Vertical Ratios (HVSR) of several ground motion
records revealed features of 1D site amplification, geotechnical site investigation data are
necessary for validation. Exceptions were the ground motions at station ARG2, which
systematically showed HVSR peaks consistent with the fundamental mode of an adjacent site,
for which shear wave velocity measurements were available. In addition, topography 3D
effects coupled to site response have likely contributed to the PGA = 0.76 g recorded at station
CHV1 and the large exceedance of its spectral acceleration values compared to code-based
values. This station presents an opportunity for learning about the complex mechanisms of
nonlinear 3D site response, and merits further investigation including site characterization and
high resolution topography mapping (e.g., through LiDAR). Finally, the large acceleration and
strikingly near-field features of the EW component recorded by station LXR1 during the 2nd
event provide a unique case study that merits further investigation as an opportunity to better
understand nonlinear site response from near-field motions.
GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐17
8.2 Liquefaction, Ports and Waterfront
INTRODUCTION
The two main shocks of the Cephalonia 2014 earthquake sequence (Event 1 and Event 2)
caused widespread liquefaction in the Lixouri and Argostoli ports (two of the four main ports)
and in adjacent waterfronts. Figure 8.2.1 shows the location of the four ports: Argostoli,
Lixouri, Sami, and Poros. Liquefaction was followed by lateral spreading, manifested by
opening of large cracks, predominantly parallel to the coastline with movement towards the
seafront. Marginal liquefaction and movement of pier blocks was also observed at the port of
Sami. No damage was observed in the port of Poros, which is located the farthest away from
the earthquake epicenters.
This section presents observations regarding the response of the waterfront in the former
three ports. The information presented in this section was gathered by: (i) the UPatras
reconnaissance team after the 1st and 2nd events, prior to the GEER/EERI/ATC team January
28-30 and February 5, (ii) collectively by the GEER/EERI/ATC team during February 8-10
(most data collected by UPatras, AUTH-LSDGEE, ITSAK, NTUA and UTH), and (iii) follow-
up reconnaissance visit by UPatras on February 18-19.
Figure 8.2.1. The four main ports in the island of Cephalonia: Argostoli, Lixouri, Sami, and Poros.
No damage Insignificant damage Moderate damage Significant damage
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐18
LIXOURI PORT
General Lixouri Port Area
The Lixouri port seafront is approximately 400 m long (Fig. 8.2.2). It was reportedly
constructed by reclaiming part of the sea using debris generated following the destructive M7.2
earthquake of 1953.
Figure 8.2.2. Google Earth photo of the Lixouri Port Area (GPS coordinates 38.20o, 20.44o).
Southern Pier
Main Pier “Davraga”
Plaza of National
Resistance
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐19
The yellow line in Fig. 8.2.2 outlines the location of the first cracks based on
reconnaissance after Event 2 that appears to coincide with the coastline prior to the 1953
earthquake. Liquefaction and lateral spreads in the Lixouri port and waterfront area were first
observed during Event 1. Eye witnesses in the port area reported that during Event 1 ejected
material reached a height of 1.5 m. Liquefaction and lateral spreads in the Lixouri port and
waterfront area were more extensive during Event 2.
Figure 8.2.3 shows an example of damage due to liquefaction and lateral spreading in
Lixouri’s quay wall following Event 1 (Fig. 8.2.3a) and following Event 2 (Fig. 8.2.3b). As
shown in Fig. 8.2.3, at this location the horizontal displacement was 9 cm and vertical
displacement was 6 cm after Event 1 (Fig. 8.2.3a). After Event 2, horizontal and vertical
displacements increased to 49 cm and 30 cm, respectively (Fig. 8.2.3b). Many sites that were
liquefied in Event 1 re-liquefied during Event 2 along the Lixouri waterfront. Figure 8.2.4
illustrates an example from the Lixouri port’s main pier, which was practically undamaged
following Event 1 (Fig. 8.2.4a), but suffered significant damage in some sections following
Event 2 (Fig 8.2.4b).
Lixouri Quay Wall
The quay wall of the Lixouri port is shown in Fig. 8.2.5. Soil ejecta found on the ground
surface and lateral spreading towards the seafront observed during reconnaissance surveys
were indicative of soil liquefaction along the Lixouri waterfront. Figures 8.2.6 through 8.2.13
present pictures of the soil ejecta and lateral spreading taken during reconnaissance surveys. In
many cases, the liquefied material was brown in color and by inspection appeared to be silty
sand or sandy silt. In some cases, grayey material was also observed (Fig. 8.2.7b). In several
occasions, the ejecta included coarse material, including coarse gravels (Figs. 8.2.7c, 8, 9, 13).
The gravel-size particles are part of the fill immediately below the ground surface. Samples of
soil ejecta were collected for classification testing. The ejecta in Lixouri port is in some places
coarser than the ejecta observed in the Argostoli port area, which may be indicative of higher
pore water pressures developed in Lixouri area.
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐20
Figure 8.2.3. Lixouri port movement following (a) Event 1 and (b) Event 2. (GPS coordinates 38.198767o, 20.439533o). George Athanasopoulos of UPatras is on the photo.
(a)
(b)
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐21
Figure 8.2.4. Damage to the main pier of Lixouri port, Davraga, following: (a) Event 1 and (b) Event 2 at (GPS coordinates 38.201500o, 20.441283o).
(a)
(b)
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐22
Figure 8.2.5. Temporary Exhibit: Quay wall of Lixouri port from postcard mailed in 1919 (Poulaki-Katevati, 2009). To be replace by Google Earth view of the quay wall. (FIGURE PENDING, SO THAT IT CAN BE UPDATED ONCE THE REST OF PHOTOS AND TEXT IS FINALIZED).
Figure 8.2.6. Soil ejecta with gravel size particles along the Lixouri port waterfont after Event 2. Note gravel size particles in the ejecta (GPS coordinates 38.19873o, 20.43934o).
Temporary Exhibit
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐23
Figure 8.2.7 Typical liquefaction ejecta in Lixouri port [GPS coordinates: a-(38.197531o, 20.439784o), b-(38.19988o, 20.43969o), c-(38.19922o, 20.43928o), d-(38.19873o, 20.43934o), 2/8/2014].
Figure 8.2.8. Example of seafront crack opening at the port of Lixouri. Note large particle size of the ejecta (38°11'55.38"N, 20°26'20.98"E).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐24
Figure 8.2.9. Extensive evidence of coarse-grained ejecta in the area of Lixouri port: (a) at quay wall (38°12'0.02"N, 20°26'22.62"E), and (b) towards the first row of buildings parallel to the shoreline (38°11'59.82"N, 20°26'21.76"E).
Figure 8.2.10. Remnants of liquefaction on the Lixouri coastal sidewalk (GPS coordinates: 38.199444, 20.439166).
(b)(a)
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Figure 8.2.11. Ejecta on Lixouri coastal sidewalk tiles (GPS coordinates: 38.199166, 20.439166).
Figure 8.2.12. Evidence of liquefaction at Lixouri coastal sidewalk (GPS coordinates: 38.199166, 20.439166).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐26
Figure 8.2.13. Evidence of liquefaction at a Lixouri coastal sidewalk (GPS coordinates: 38.199166, 20.439166).
Figures 8.2.14 through 8.2.33 present examples of displacement patterns observed at the
Lixouri port seafront. Measurements of cumulative horizontal displacement were performed
by the UPatras team along several cross-sections perpendicular to the shoreline, whose results
are currently being analyzed. Figure 8.2.20 shows two example cross-sections with
corresponding values of total horizontal displacement. Soil cracking observed in the Lixouri
coastal zone extended inland from the Lixouri waterfront to a maximum of two to three blocks
spanning about 100 m. Displacement measurements were made along cross-sections A-A' and
B-B', presented in Figs 8.2.32 and 8.2.33, respectively. The locations of the cross sections are
shown in Fig. 8.2.2. Cumulative horizontal displacement measured along these cross-sections
from points A and B are shown in Figs. 8.2.34 and 8.2.35, respectively. Total horizontal
displacement towards the sea estimated along cross-sections A-A' and B-B' were
approximately 1.5 m and 0.55 m, respectively. Longitudinal cracks parallel to the seafront were
observed as far as 100 m inland from the Lixouri waterline. However only small amount of
these displacements are due to lateral ground spreading, they are mostly due to inertia sliding
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐27
of the blocks constituting the quay wall, as well as, the differential settlement at the base of the
quay wall. Displacements due to lateral spreading were extending over a zone of about 15 m
behind the quay wall (Fig. 8.2.34). Whereas, displacements that can be attributed to inertia-
induced sliding and differential settlement (i.e. rotation) of the qual wall develop over a very
short distance from the quay wall, as shown in Fig 8.2.34 and 8.2.35 by the steep increase
observed in cumulative displacement near the quay wall.
Figure 8.2.14. 180 degrees panorama view of the displacement patterns at the Lixouri port in location: 38°11'53.53"N, 20°26'22.23"E.
Ejected material next to the displaced quay walls was not equally distributed in all
locations. The liquefaction ejecta are not as abundant as in the foreground where the quay wall
did not displace as much, due to the restraint provided by the small wharf located perpendicular
to it. The ramps made for the access of cars into the ferries provided adequate restraint to lateral
quay wall displacement as shown in Fig. 8.2.22a. Fig.8.2.26 shows that the displacement and
rotation of external corner quay walls were significantly more severe compared to the other
parts of the quay wall, showing the 3D geometry effects. Profound liquefaction ejecta evidence
was observed in the foreground, for the cases where the wall was displaced and significantly
damaged substantially as in Fig. 8.2.16. The outward horizontal displacement in Fig. 8.2.16
has been estimated from the sum of the widths of the cracks to be about 70 to 120 cm. This
observation in the Lixouri Port is consistent with previous studies that demonstrated that lack
of lateral outward displacement causes development of excess pore water pressures and
ultimately liquefaction (Dakoulas & Gazetas, 2008).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐28
Figure 8.2.15. Example of the displacement patterns at the Lixouri quay wall (38°11'52.99"N, 20°26'22.48"E).
Figure 8.2.16. Lateral displacement of the quay wall, and ejected liquefied soil. This is abundant where the wall has not displaced horizontally due to the small perpendicular wharf restraining it. (GPS coordinates: 38.199444, 20.439166).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐29
Figure 8.2.17. Vertical displacement observed behind the wavefront (marked with the yellow curve) and opening of a road-pavement joint (GPS coordinates: 38.199166, 20.439444).
(a)
(b)
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐30
Figure 8.2.18. Cracks in the road behind the quay wall and liquefaction remnants on the sidewalk (GPS coordinates: 38.199166, 20.439444).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐31
Figure 8.2.19. Vertical diaplacement behind quay wall exposing water network pipes (GPS coordinates: 38.199166, 20.439444).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐32
Figure 8.2.20. Lateral displacement of the quay wall towards the sea (GPS coordinates: 38.199166, 20.439444).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐33
Figure 8.2.21. Vertical settlement behind the quay wall reaching 70 cm (GPS coordinates: 38.199166, 20.439444).
70 cm
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐34
Figure 8.2.22. Across the Plaza of National Resistance (shown in Fig. 8.2.2), damage consisted mainly of lateral quay wall displacement and road cracks (GPS coordinates: 38.199444, 20.439444).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐35
Figure 8.2.23. Lateral quay wall displacement and road cracks in the southern part of Lixouri port (GPS coordinates: 38.199444, 20.439444).
Figure 8.2.24. Settlement behind the quay wall (GPS coordinates: 38.199722, 20.439722).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐36
Figure 8.2.25. Cracks in the southern part of the Lixouri port (GPS coordinates: 38.199722, 20.439722).
Figure 8.2.26. Settlement and cracks behind the quay wall (GPS coordinates: 38.199558, 20.439852).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐37
Figure 8.2.27. Uneven surface settlement due to lateral spreading and liquefaction of the wharf backfill (GPS coordinates: 38.199627, 20.440022).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐38
Figure 8.2.28. Light brown color sand liquefaction ejecta (GPS coordinates: 38.200000, 20.440000).
(a)
(b)
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Figure 8.2.29. Soil liquefaction remnants behind the quay wall and lateral displacement towards the sea front (GPS coordinates: 38.200277, 20.439383).
Figure 8.2.30. Cracks behind the wall and sand remnants of liquefaction ejecta (GPS coordinates: 38.201050, 20.439297).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐40
Figure 8.2.31. Auxiliary dock on quay wall, located to the north of main dock in the port of Lixouri: (a) from 2011 archives {www.panoramio.com/photo/3072045?source=wapi&referrer=kh.google.com}; and after the 2nd event: (b) front and (c) back (38°12'1.39"N, 20°26'21.85"E).
Figure 8.2.32. Lateral movement in Lixouri port along section A-A' of Fig. 8.2.2 being measured by Tasos Batilas and Xenia Karatzia of UPatras on 2/8/14 (GPS coordinates 38.19842 o, 20.43956 o).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐41
Figure 8.2.33. (a) Lateral spread in Lixouri port along section B-B' and (b) movement of quay walls (GPS coordinates: a-(38.20072o, 20.43920 o), b-(38.20077 o, 20.43940 o), 2/8/14).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐42
Figure 8.2.34. Plot of cumulative horizontal displacement vs. distance from point A (as shown in Fig. 8.2.2) at Lixouri port.
Figure 8.2.35. Plot of cumulative horizontal displacement vs. distance from point B (as shown in Fig. 8.2.2) at Lixouri port.
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐43
Lixouri Main (North) Pier Davraga
The performance of the main pier at the north of the Lixouri port of Davgara (Fig. 8.2.2)
varied from excellent to poor. Figure 8.2.36 illustrates the main pier and has annotated the
regions that exhibited significant damage.
Figure 8.2.36. Temporary Exhibit to be replace with Google Earth view of the Davraga Main pier [to be added after text and remaining photos are finalized).
Images such as the one shown on Fig. 8.2.37 caught significant media attention. The main
pier appeared to be largely undamaged following Event 1, but in some places suffered heavy
damage during Event 2. The pier has been constructed in phases. As a result, different sections
suffered variable levels of damage (Fig. 8.2.38 to 40), depending on the construction and
geometric aspects of the pier. Surveying measurements have been performed and results are
currently being processed by the UPatras team.
The largest outward displacement was observed in the main pier Davraga (Fig. 8.2.41
through Fig. 8.2.52). The initial portion of the pier, of about 50 m in length, exhibited the
largest displacement of about 1.5 m. The following 50 m portion displaced much less, perhaps
less than 0.5 m, apparently due to the much greater width of its blocks. Damage of this portion
took place only on the south side, since the north side, which serves as breakwater, had a very
shallow water depth and was supported by huge rock blocks (monoliths) playing the role of
the tripods that are used in major breakwaters.
Given the large displacements observed at the surface, exceeding 1 m in several locations,
and the large friction angles between blocks, it is likely that the base block translated
horizontally and rotated away from the backfill by a significant amount. This mechanism is
Temporary Exhibit
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐44
consistent with observations of quay wall behavior under strong seismic shaking during
previous events (Iai 2001, Dakoulas & Gazetas 2008). Whereas currently the relative amounts
of translation and rotation cannot be precisely determined, an assumed rotation of the base
block by about 10 degrees is considered sufficient to produce the observed displacement at the
top. The rubble fill behind the wall certainly liquefied, but the contribution of the liquefied soil
to the horizontal displacement of the quay wall is not clear, since the wall may have moved
simply due to its substantial mass, and the potential for significant compliance/limited strength
of the base material. Detailed measurements are required to assess the contribution of the
various mechanisms to the observed response. It is noted that no simple design
recommendations exist to date to limit the deformations of this particular type of structure to
high levels of seismic shaking experienced during the recent events.
Cross-sections through the eastern-most (Fig. 8.2.50) and most recently constructed (in
2007) part of the main pier, whose locations are shown in Fig. 8.2.36, are shown in Figs. 8.2.53
to 8.2.56 (data provided by Kostas Rouchotas of NTUA and sketches developed by Adam Dyer
of MRCE). The pier wall body consists of four blocks having total height of 7 m and width
ranging between 5 and 6.25 m. The design incorporated standard features such as drainage,
geotextile interfaces, rubble fill, etc.
Few years ago, the protection slab at the foot of the pier at its easternmost section was
accidentally damaged by a jack up drilling vessel that penetrated 2 m under the slab and
ruptured the geotextile, in an effort to keep the vessel stable during rough weather. The edge
column in that location fell during the earthquake, but it is unknown to what extent failure is
associated with this specific damage. Overall, however, this portion of the main pier has moved
much less than the other sections of the pier.
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Figure 8.2.37. Example of liquefaction damage and lateral spreading at the most damaged section of the main pier (38°12'5.12"N, 20°26'22.40"E).
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Figure 8.2.38. Most damaged section of the main pier (38°12'3.32"N, 20°26'22.92"E).
Figure 8.2.39. Another section of the damaged main pier (38°12'3.30"N, 20°26'23.02"E).
GEER/EERI/ATC GEER/EERI/ATC Cephalonia, Greece 2014 8‐Geotechnical Observations Report Version 1 8‐47
Figure 8.2.40. State of the main (Davraga) pier in Lixouri port): (a) Before the 2 events, from 2011 archives {www.panoramio.com/photo/59409701?source=wapi&referrer=kh.google.com}; (b) after the 2nd event (38°12'5.02"N, 20°26'21.73"E).
(a)
(b)
(a)
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Figure 8.2.41. Damage of quay wall in Davraga pier. Sailboats overturned (GPS coordinates: 38.201050, 20.439297).
Figure 8.2.42. Lateral spreading and differential horizontal displacement along Davraga main pier wall. Note the different wall width shown with white arrows (GPS coordinates: 38.201436, 20.440202).
≈ 2 m
1.2 m
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Figure 8.2.43. Horizontal displacement and rotation of wall of main pier (GPS coordinates: 38.201483, 20.439452).
Figure 8.2.44. Vertical settlement behind the wall of photo 8.2.43 (GPS coordinates: 38.201397, 20.439511).
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Figure 8.2.45. Southern side of main pier, the only side where damage was observed. Presence of large monoliths at the northern side had a positive effect by restricting lateral movement (GPS coordinates: 38.201666, 20.440000).
Figure 8.2.46. Lateral movement is greater behind the narrower wall of the main Lixouri pier (GPS coordinates: 38.201466, 20.440158).
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Figure 8.2.47. Cracks along main Lixouri pier dock surface (GPS coordinates: 38.201486, 20.441266).
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Figure 8.2.48. Rotation and lateral movement of main pier. Prof. G. Gazetas of NTUA shown on top photo (GPS coordinates: 38.201269, 20.440977).
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Figure 8.2.49. Vertical displacement of main pier marked with yellow arrow (GPS coordinates: 38.201269, 20.440977).
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Figure 8.2.50. Panoramic views of the eastern-most section of Davraga pier.
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Figure 8.2.51. Main pier: (a) opening of horizontal joint; (b) monolith breakers constraining lateral movement; (c) concrete slabs settlement; and (d) detail of vertical settlement in yellow arrows (GPS coordinates: 38.201611, 20.442094).
(a)
(b) (c)
(d)
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Figure 8.2.52. State of eastern most section of main pier of Lixouri port: (a) from 2011 archives, {www.panoramio.com/photo/49466386?source=wapi&referrer=kh.google.com} with jack up drilling vessel that reportedly caused pier damage, and (b) after the 2nd event (38°12'6.14"N, 20°26'32.08"E).
(a)
(b) (b)
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Figure 8.2.53. E-W cross section of eastern-most section of main pier of Lixouri Port. Data collected by Kostas Rouchotas of NTUA team. Sketch by Adam Dyer of MRCE.
Figure 8.2.54. N-S cross section of eastern-most section of main pier in Lixouri Port. Data collected by Kostas Rouchotas of NTUA team. Sketch by Adam Dyer of MRCE.
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Figure 8.2.55. Detailed drawing of the sketch of Fig. 8.2.53 developed from data by Kostas Rouchotas of NTUA team showing E-W cross section of eastern-most section of main pier of Lixouri Port.
Figure 8.2.56. Detailed drawing of the sketch of Fig. 8.2.54 developed from data by Kostas Rouchotas of NTUA team showing N-S cross section of eastern-most section of main pier in Lixouri Port.
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Lixouri South Pier and Lighthouse
The seismic settlement of the breakwater and lighthouse at the south entrance of the Lixouri
port is also of interest. As shown in Figs. 8.2.57 to 8.2.60, the lighthouse and the supporting
rip-rap appear to have settled. Discussions with the lighthouse operator, photos prior to the
earthquakes, and measurements indicate that: (a) the lighthouse had been settling since its
construction and (b) additional (currently unquantified) settlement took place during Event 2.
Figure 8.2.57. State of lighthouse at Lixouri breakwater tip: (a) from 2011 archive photo {www.panoramio.com/photo/50853069?source=wapi&referrer=kh.google.com}, and (b) after the 2nd event (38°12'3.70"N, 20°26'35.41"E).
(a)
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Figure 8.2.58. View of breakwater with the lighthouse (left: 38°11'53.97"N, 20°26'22.06"E; right: 38°12'4.90"N, 20°26'37.09"E).
Figure 8.2.59. Detailed view of the light-house’s settlement (a) From an online picture dated 5/8/09; and (b) after the 2nd event (GPS coordinates: 38.200897, 20.443222).
(a) (b)
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Figure 8.2.60. Light house settlement views (GPS coordinates: 38.200897, 20.443222).
The southern arm of the port serves as a small-boat marina and experienced from negligible
to minor damage. As shown in Figs. 8.2.61 and 8.2.62, in the first part of this marina, the quay
wall had neither cracks nor seaward displacement, apparently as a result of shallow water depth
of less than 2 m. In the most damaged section part of the marina (Figs. 8.2.63 and 8.2.64),
cracks appeared accompanying a 20 to 30 cm seaward displacement of the quay wall. The
displaced main quay wall and the liquefaction of the fill over a substantial distance from it
contributed to lateral spreading, and was demonstrated with cracks in the pavement and the
sidewalks over a distance of 2 blocks (Fig. 8.2.65).
Figure 8.2.61. Southern part of Lixouri port that experienced only minor cracks (GPS coordinates: 38.197944, 20.441044).
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Figure 8.2.62. Land reclamation on the outer side of the southern marina prevented lateral displacements of the shallow quay wall. The ejected liquefied soil on the reclaimed land is abundant (GPS coordinates: 38.197944, 20.441044).
Figure 8.2.63. Settlement of the coastal road and cracks on road surface (GPS coordinates: 38.198372, 20.439483).
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Figure 8.2.64. Detailed views of the south part of Lixouri port: (a) and (b) minor cracks behind the wall, (c) shallow water level (GPS coordinates: 38.198158, 20.442222).
(b)
(c)
(a)
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Figure 8.2.65. Sidewalk, pavement cracks and road settlement (GPS coordinates: 38.201102, 20.438855).
Some evidence of liquefaction was observed to the south of the port of Lixouri (Fig.
8.2.66), but is more limited. The limited number of liquefaction evidence may be attributed to
a number of rainfall events that might have “washed away” the soil ejecta.
Figure 8.2.66. Liquefaction zones observed along Lixouri port (GPS coordinates 38.20o, 20.44o).
Liquefaction zone
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ARGOSTOLI PORT
Historical Information
Argostoli is Cephalonia’s capital since 1757 (Fig. 8.2.67) with a population of 8,000
people, one-third of the island’s inhabitants. Historically, it has been reported that the entire
coastal area of Argostoli was destroyed (Figs. 8.2.68 and 8.2.69) following the catastrophic
series of the 1953 earthquake events with magnitude Ms of 7.3 and modified Mercalli intensity
of IX-X (Stiros et al., 1994, and Papagiannopoulos et al., 2012.)
Figure 8.2.67. Old painting of Argostoli port, ca. 1757 (ref: Wikipedia).
Figure 8.2.68. Argostoli port after the 1953 earthquake, looking west from above the town bridge (Bittlestone, 2005).
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Figure 8.2.69. Argostoli quay wall damage after the 1953 event (Papathanassiou & Pavlides, 2011).
The port was rebuild through reclamation of the sea using fill materials that were, to a large
extent, debris of collapsed or demolished masonry buildings (Fig. 8.2.67). New construction
on the reclaimed land zone used mostly reinforced concrete mat foundations (thickness ~ 0.60
m) with a foundation depth of probably not more than 1.5 m.
Liquefaction Observations
Following the 2014 earthquake events, the Argostoli port (Fig. 8.2.70) and adjacent
coastline experienced liquefaction and lateral spreading. The town’s waterfront is
approximately 1.1 km in length. Soil liquefaction was observed throughout the Argostoli
waterfront, most evident in particular areas. In general, the damage in the Argostoli port was
less severe than the damage in the Lixouri port, which was closer to the earthquake epicenter.
Liquefaction was manifested by soil craters and ejecta, and cracks in paved surfaces
surrounded by large amounts of ejecta (Fig. 8.2.71). No signs of liquefaction were observed
beyond an inland distance of 100 m from the waterfront.
Figure 8.2.70. Panoramic view of the Argostoli port following the two 2014 seismic events.
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Figure 8.2.71. Examples of soil craters and ejecta along the waterfront of Argostoli port GPS coordinates a-(38.18105o, 20.48955o), b-(38.118118o, 20.48954o), c-(38.180752°, 20.489990°), d-(38.17118o, 20.49600o)].
Photos of liquefaction manifestation surrounding the customs building in the Argostoli port
is shown in Fig. 8.2.72 through Fig. 8.2.75. One of the accelerograph stations installed after
the 1st event, on January 30th 2014, in the region by the Geotechnical Engineering Laboratory
of UPatras was placed inside the Customs Building of Argostoli, in close proximity to observed
liquefaction triggered by the 1st event. This instrument recorded the 2nd event, which caused
more extensive soil liquefaction at the same location (Fig. 8.2.72). This location represents an
interesting case of re-liquefaction, similar to the cases described in the 2010-11 New Zealand
earthquakes (GEER, 2011). The availability of recorded horizontal surface acceleration in the
vicinity of soil liquefaction, combined with site characterization data, has the potential to
generate another well-documented case history of soil liquefaction (Batilas et al., 2014).
(a) (b)
(c) (d)
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Figure 8.2.72. Ejecta material outside the Customs Building of Argostoli where the UPatras Geotechnical Engineering Laboratory strong motion station is located [GPS coordinates: a: (38.18010o, 20.48993o), b: (38.17998o, 20.48996o)].
Figure 8.2.73 presents evidence of ejecta in the area of the Port Authority complex of
Argostoli, where the abundance of gravel and the existence of even small cobbles (maximum
diameter of 3 cm) was observed. This is not typical for ejecta, which usually consist of finer
particles. However, it is not clear at this point, whether the gravelly soil did indeed liquefy or
if the gravelly particles were ejected out under the high water pressure. In any case, these
particle sizes are very uncommon for ejected material.
Figure 8.2.74 presents evidence of the maximum height of ejected soil-water mixtures in
the perimeter of one the Port Authority complex buildings at Argostoli. The measurement reads
clearly a height of 35 cm of ejecta, with finer soil mark evidence reaching a height of 50 cm,
indicative of the high pore water pressures.
(a)
(b)
(1/29/14)
(1/29/14)
(2/18/14)
(2/18/14)
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Figure 8.2.73. Evidence of ejecta in the Port Authority building area at Argostoli (38°10'47.85"N, 20°29'24.42"E).
Structural Settlements
Evidence of rigid body rotation due to differential liquefaction-induced settlements is
presented in Fig. 8.2.75 for a single story R/C frame building at the Port Authority complex in
Argostoli. The settlement is greater towards the sea (i.e., to the east), and led to rigid body
rotation of about 1o without causing structural damage. Additional settlement observations are
discussed in the Settlement and Soil-Structure Interaction section of this chapter.
Figure 8.2.74. Evidence of maximum height of ejected soil-water mixtures against the wall of a Port Authority building at Argostoli (38°10'47.50"N, 20°29'23.43"E).
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Figure 8.2.75. Rigid body rotation of a single story R/C frame building (at left) due to differential liquefaction-induced settlements at Port Authority complex in Argostoli (38°10'47.91"N, 20°29'23.47"E): (a) view towards the south, (b) view towards the north.
Lateral Movements
As a result of soil liquefaction and the presence of a free face, large cracks opened in the
port area of Argostoli as well as along the asphalt-paved coastal street of the town. The cracks
were, in general, parallel to the waterfront and their widths decreasing with increasing inland
distance from the waterfront. No signs of surface cracking were observed beyond the first row
of buildings adjacent to the coastal street. Measurements of crack widths were performed along
several cross-sections, perpendicular to the waterfront and the total displacement was recorded.
Significant lateral movements, extensive cracking and joint openings were observed
especially in the large dock of Argostoli port (38.181o, 20.489o), as shown in Fig. 8.2.76. The
length and the width of dock are approximately 210 m and 80 m, respectively. The maximum
lateral displacements was observed along line A-A' and was about 9 cm. At the north side of
the dock, the lateral displacement was approximately 6 cm while at the south was about 16 cm.
Fig. 8.2.77 through Fig. 8.2.80 illustrate the damage, and the measurements performed.
(a) (b)
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Figure 8.2.76. Google Earth photo of the central dock of Argostoli port. Red arrows indicate development of excessive cracking and lateral spreading.
Figure 8.2.77. Quay wall at dock of Argostoli port: (a) wall outward movement and (b) cracks due to lateral spreading dated 2/9/14. GPS coordinates: a-(38.17955o, 20.48987o), b-(38.17955o, 20.49011o).
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Figure 8.2.78. Outward movement of quay wall and vertical displacement in front of the main Argostoli port dock measured by Tasos Batilas of UPatras (GPS coordinates 38.18024o, 20.49034o, 9/2/2014).
Figure 8.2.79. (a) Photograph of lateral movement and (b) settlement of ground behind the quay wall (GPS coordinates 38.18137o, 20.48980o, 9/2/2014)
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Figure 8.2.80. Argostoli port cumulative horizontal displacement vs. distance from A (see Fig. 8.2.75).
Liquefaction and damage associated with lateral movement of the seafront was also
observed beyond the central dock, as shown in Fig. 8.2.81, and measurements have been
collected. The port quay wall displaced about 10 cm on average, creating a gap and separating
from the sidewalk, as shown in Figs. 8.2.82 through 8.2.84. The performance of the port quay
wall can be considered satisfactory given the PGA (Peak Ground Acceleration) levels in excess
of 0.35g that was recorded at the Customs building of the port.
Figure 8.2.81. Liquefaction observations at Argostoli coastal area (GPS coordinates 38.17o, 24.49o).
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Figure 8.2.82. Quay wall view south of the Argostoli Port Authority building complex: (a) from 2011 archives {www.panoramio.com/photo/57109645?source=wapi&referrer=kh.google.com} and (b) after the 2nd event (38°10'45.96"N, 20°29'22.51"E).
(a)
(b)
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Figure 8.2.83. Minor displacement of quay wall (GPS coordinates: 38.176938, 20.490008).
Figure 8.2.84. (a) Vertical settlement of the backfill soil and (b) signs of liquefaction on the road surface (GPS coordinates: 38.179525, 20.489597).
(a)
(b)
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Underwater Surveying
An underwater camera survey conducted following the earthquakes in the Lixouri and
Argostoli ports (provided by team member Kostas Rouchotas of NTUA), identified that the
quay wall blocks were as far as 30 cm apart (see Figs. 8.2.85 and 8.2.86), significantly higher
than the general acceptable range for seismic design between 2 and 5 cm.
Figure 8.2.85. Underwater view of a 30-cm gap between blocks in Argostoli quay wall.
Figure 8.2.86. Underwater view of 20-cm gaps between blocks in Argostoli quay wall.
Figure 8.2.87. Underwater view of scour under base block in Argostoli quay wall.
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Granular material from the backfill may have passed through these gaps and gradually
washed out, generating cavities in the retained mass that were stable under static conditions
possibly due to soil arching, but collapsed during earthquake shaking. It is also likely that
during the earthquake shaking, the high pore pressures generated in the liquefied soil backfill
were released through these openings. This mechanism would explain the settlement of the
backfill immediately adjacent to these blocks and the lack of sand boils on the ground surface.
In addition, block movements in the two ports were apparently aggravated due to the surveyed
scour depth of 10 to 20 cm, extending as far as 1 m under the base blocks (Fig. 8.2.87).
Figure 8.2.88. Visible evidence of soil liquefaction at southeast part of Argostoli port (GPS coordinates: 38.171197, 20.495725]
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Liquefaction was also evident on the ground surface on the south coast where the water
depth is of the order of 1 m, and the wall hardly displaced at all. The consequences were not
significant (Figs. 8.2.88 through 8.2.90).
Figure 8.2.89. Sand boils on the free surface, southeast part of Argostoli port (GPS coordinates: 38.171100, 20.495930).
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Figure 8.2.90. Sand boils on the free surface in the southeast part of Argostoli port (GPS coordinates: 38.171166, 20.496000).
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PORT OF SAMI
The effects of earthquake shaking during both events in Sami port, at an epicentral
distances greater than 25 km, were less severe to those observed at the Lixouri and Argostoli
ports that were closer to the epicenters (less than 10 km). Minor damage was observed in the
yellow-shaded areas of Figure 8.2.91.
Figure 8.2.91. Port of Sami. Detailed damage shown on Fig. 8.2.92 for the area in lower annotated circle, and in subsequent figures for the upper circle area which experienced more significant damage. Figure 8.2.92. Post-earthquake damage observation in the lower annotated circle area of Fig. 8.2.91 at the Sami port.
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Liquefaction-induced phenomena were not clearly observed in the port area of Sami. Only
minor displacements, opening of joints between concrete pier blocks and formation of new
cracks associated with settlement of pier blocks were observed and traces of what appeared to
be minor soil liquefaction (Figs. 8.2.91 to 8.2.94). Possible evidence of ejecta may have been
washed out due to significant rainfall in the days preceding the reconnaissance in this area.
Figure 8.2.93. Crack following the 2nd event at Sami port main pier (38°15'14.97"N, 20°38'50.56"E).
Figure 8.2.94. Joint opening between blocks at Sami port pier with possible ejected sandy soil material at the deepest water area of the pier. This was the only location where these questionable sandy ejecta were identified (38°15'14.93"N, 20°38'51.60"E).
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BROADER PALIKI PENINSULA
Scattered limited liquefaction phenomena were identified at three locations of Paliki
peninsula:: (i) a sand crater with diameter less than 5 cm in a stream bank that crosses plio-
pleistocene sediments was observed in Soulari (Fig. 8.2.95); (ii) brown coarse sandy material
ejected through a crack at the edge of a paved road in Kounopetra of south Paliki peninsula
(Fig. 8.2.96a); and (iii) a small amount of coarse sandy material ejected through a fissure with
width less than 2 cm inside a field between the villages of Atheras and Livadi (Fig. 8.2.96b).
Figure 8.2.95. Evidence of liquefaction in Soulari (38,18996; 20,41198).
Figure 8.2.96. (a) Evidence of liquefaction in Kounopetra (38,15726; 20,38534). (b) Ground cracking with limited evidence of sand boils in a field between Atheras and Livadi (38,298547; 20,418600).
(a) (b)
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CONCLUSIONS
Widespread soil liquefaction and re-liquefaction occurred in the coastal zones and ports of
Lixouri and Argostoli, as a result of earthquake shaking in both events 1 and 2, and was
documented by the reconnaissance teams in this section. Damage in the port of Lixouri was
more severe than the damage in the port of Argostoli. The observed difference in performance
can be partially attributed to the distance from the epicenters and the shaking intensity.
Liquefaction in the Lixouri port was abundant in the top backfill, which is made of sand with
gravels and occasionally, boulders. Liquefaction contributed to the quay wall displacement and
was accompanied by lateral spreading. Lateral spreading towards the sea direction together
with the inertia sliding of the blocks constituting the quay wall and the differential settlement
at the base of the quay wall resulted in a total seaward displacement exceeding 1.5 m in Lixouri.
The outward differential displacement of the quay wall in Argostoli was significantly lower.
The other two ports of Sami and Poros did not suffer significant damage. Very minor damage
was observed in the port of Sami, located about 25 km from the epicenter of the 2nd event, and
no damage in the port of Poros, which was located 35 km from the epicenter. Liquefaction
boils and ground failure probably associated with liquefaction was also observed away from
Lixouri in three locations in the Paliki peninsula.
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8.3 Earth Retaining Structures INTRODUCTION
The response of earth retaining structures subjected to strong ground motions has been the
subject of several case studies and growing evidence of good performance has lately
accumulated (Lew et al. 2010). In addition, recent experimental and numerical parametric
studies (Al-Homoud and Whitman 1999, Gazetas et al. 2005, Lee 2005, Al Atik and Sitar,
2010, Athanasopoulos-Zekkos et al. 2013) have demonstrated that, at least in the case of
yielding retaining walls, the large phase difference developed between the wall inertial force
and dynamic increment of earth pressure, may be the main factor contributing to their
satisfactory field response.
OVERVIEW OF RETAINING WALLS IN CEPHALONIA
The majority of earth retaining structures in Cephalonia is masonry, or even dry-stacked,
retaining walls ranging in height from 1.0 m to 5.0 m and used to support roadway cuts and
backfills adjacent to commercial or residential buildings. A smaller number of concrete walls
(of gravity or cantilever type) have also been used in newer construction. Retaining walls of
both types were subjected to strong ground motions during the two main earthquake events of
January 26 and February 3, 2014. Their response varied based on their distance from the
epicentral area and type. Stone masonry walls were in general more vulnerable compared to
concrete walls with a typical damage pattern being out-of-plane collapse, away from the
backfill. The stone masonry walls were typically made of limestone blocks with varying quality
of construction. In some cases the limestone blocks were simply dry-stacked, whereas in other
cases, different amounts of cement was used. Thus, besides the significant earthquake-induced
earth pressures and accelerations imposed on these walls, possible structural deficiencies and
poor condition of cement should be considered in interpreting the observed damages. Some
characteristic case histories of performance are presented in detail in the following.
This section summarizes reconnaissance observations made by the UPATRAS, NTUA,
ITSAK, DUTH, AUTH-LSDGEE and UTH teams during the periods of 27-30 January, 4-5,
8-12, 18-20 and 22-23 February of 2014. A total of 36 seismically-induced failures on retaining
walls were recorded mainly in the Paliki peninsula after the 1st event (EPPO-ITSAK, 2014)
and the 2nd event. The spatial distribution of recorded failures is shown on Fig. 8.3.1.
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Figure 8.3.1. Geographical distribution of 36 retaining wall failures following the 1st and 2nd events. Original figure shows stone masonry retaining walls (to be updated in next version).
MASONRY EARTH RETAINING WALLS
A multi-tiered wall supporting a backfill in Chavriata village is shown in Fig. 8.3.2 with a
schematic in Fig. 8.3.3. The Panayia Agriliotissa church was partially supported by the backfill.
Fig. 8.3.2a depicts the condition of the wall prior to the 2014 earthquakes from a 2007 archive.
The three-tiered wall sustained some damage during the 1st event (Fig. 8.3.2b) and was
significantly damaged and actually collapsed during the 2nd event (Fig. 8.3.2c). As a result,
lateral displacement and settlement of the backfill retained by the wall resulted in heavy
damage of the church. This retaining wall is in close proximity (about 200 m) to a strong motion
instrument that recorded a peak horizontal ground acceleration PGA of ~0.74 g during the 2nd
event. Fig. 8.3.4 and 8.3.5 are close-up views from the southwest and south, respectively.
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Figure 8.3.2. Retaining wall and historical church at Chavriata village: (a) before the 2 events, (b) following the 1st event; and (c) following the 2nd event; (38°10'57.52"N, 20°23'13.61"E). Photo (a) is from 2007 archives: www.panoramio.com/photo/50007113?source=wapi&referrer=kh.google.com
(a)
(b)
(c)
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Fig. 8.3.3. Schematic of the Panayia Agriliotissa Church, prepared by S. Valkaniotis (modified from Papathanasiou et al., 2014).
Of interest is also that immediately downhill of the failed multi-tiered masonry wall of
Figures 8.3.2 to 8.3.5 are two approximately 5-m high masonry walls with significant cement
between blocks that responded much better to the two events, despite being subjected to the
same intense shaking (Fig. 8.3.6).
As shown in Figure 8.3.6b, the first wall, in the foreground, is directly downhill the failed
multi-tiered masonry wall (note its debris to the right), while the second one, in the background,
starts at this location and is running towards the west, in parallel, but further to the west of the
wall in the foreground. The second wall displaced horizontally and as a result a longitudinal
crack to the pavement was observed. This wall is quite long, and its behavior further to the
west of the church is presented in the section of concrete retaining walls below. The
longitudinal crack also continued behind the first wall with smaller dimensions.
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Figure 8.3.4. View of the retaining wall and church (a) from the southwest; and (b) from the south following the 2nd event (38°10'57.52"N, 20°23'13.61"E).
Figure 8.3.5. Closer views of the damaged wall (GPS coordinates: 38.182500, 20.387222).
Figure 8.3.6. View of the masonry retaining wall, just downhill of the three-tiered plastered masonry wall in Chavriata (38°10'57.52"N, 20°23'13.61"E).
(a) (b)
(a) (b)
(a) (b)
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Another example of out-of-plane collapse of a stone masonry retaining wall was also
responsible for the closure of the road connecting the Vouni and Chavriata villages
(38.177692° N, 20.397458° E) as shown in Figure 8.3.7. Adjacent to the failed stone masonry
wall, a reinforced concrete retaining wall responded in a very satisfactory manner with no
obvious damage observed following the two strong earthquakes.
Figure 8.3.7. Extensive failure of stone masonry retaining wall followed by road embankment sliding failure with horizontal and vertical displacement. This major failure is on the roadway connecting the villages of Vouni and Chavriata (38.177692°N, 20.397458°E). The reinforced concrete retaining wall shown in yellow dotted circle suffered no damage although adjacent to the collapsed one.
In the church of Vouni village (38.177578oN ,20.403477oE) a multi-tiered, 4.7 m high (in
total), stone masonry retaining wall collapsed after the 2nd event of 2/3/14, as shown on Figure
8.3.8a. The tiers, starting from the lower one had a height of 1.2, 1.2, and 2.3 m. The length of
the failed section was approximately 20 m and engaged the lower two tiers. Partial collapse of
the wall had taken place during the 1st event of 1/26/14 (Figure 8.3.8b).
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Figure 8.3.8: (a) Collapse of lower two levels of a three-level stone retaining wall supporting the bearing soil of a Vouni village church (38.177578o N, 20.403477o E) after the 2nd event, and (b) partial collapse of the same wall following the 1st event.
Figure 8.3.9. Single-story building close to Kouvalata village (38.234484° N, 20.419554° E): (a) failure of stone masonry retaining wall followed by local landslide of the supporting bearing soil after the 1st event, and (b) progression of failure after the 2nd event.
(a)
(b)
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Failure of masonry wall was recorded following the 1st event near the Kouvalata village
(38.234484° N, 20.419554°E). The wall retained a natural slope upon which a single-story
structure was founded (Figure 8.3.9). The failure of the wall was accompanied with settlement
of the retained backfill that became more pronounced following the 2nd event. The heavy
rainfall that occurred during that period probably contributed to the evolution of this failure.
Another interesting case of masonry earth retaining wall involves a 3.3-m high wall
supporting the yard (“perivolos”) of Aghios Ioannis Chrysostomos church on steep ground in
Kourouklata village. The location of Kourouklata is approximately 10 km east of the epicenters
of the two events. The bell tower of this church was heavily damaged. Fig. 8.3.10 depicts the
yard of the church which underwent settlement and lateral displacement.
The church’s yard is retained by the masonry wall, which is flanked by concrete retaining
walls. It appears that the entire masonry wall moved and the backfill movement occurred only
behind the section retained by the masonry wall (Figs. 8.3.10, 11). The cracked ground parallel
to the wall was 24 m long. The cumulative vertical displacement of the ground was 20 cm in
the vertical direction (Fig. 8.3.12) and 21 cm in the horizontal direction. Interestingly, next to
the church lies a cemetery that is almost entirely destroyed by the earthquakes with toppling
observed in almost two thirds of the tombs.
On the road towards the Kourouklata village, there were also a few additional interesting
failures of stone masonry walls. A pair of failures is shown in 8.3.13 and 8.3.14. One was
located on the uphill side of the road, whereas the second one is located in the downhill side of
the road just a few meters apart from each other. Fig. 8.3.13 shows a view of the uphill wall,
which is 4.20 m high and has collapsed leaving the road pavement cantilevered. Fig. 8.3.4
shows a side view of the downhill wall. The natural stones were cemented. The wall has a
maximum height of 2.8 m and a thickness of 45 cm. A series of additional failures of short
retaining walls are shown also in Fig. 8.3.15 and 8.3.16.
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Figure 8.3.10. Damage at Kourouklata village church. (a) cracked ground in foreground with wall to the right and church in background; (b) ground deformations taken by Prof. G. Athanasopoulos, V. Kitsis and O. Theofilopoulou; (c) damage at cemetery behind the church; (d) concrete wall adjacent to masonry wall from lower elevation; and (e) view of wall damage (38°14'31.72"N, 20°28'25.40"E).
(a)
(b) (c)
(d) (e)
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Figure 8.3.11. Lateral soil movement, at Kourouklata’s church front yard (38.242113, 20.473955).
Figure 8.3.12. Vertical settlement of 20 cm behind the retaining wall (38.242113, 20.473955).
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Figure 8.3.13. Masonry wall damage towards Kourouklata village. (38°14'26.29"N, 20°28'35.14"E)
Figure 8.3.14. Another masonry wall damage towards Kourouklata village (38°14'26.29"N, 20°28'35.14"E).
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Figure 8.3.15. Retaining wall failures at several locations in Kourouklata village (38.241075N, 20.475602E).
Figure 8.3.16. Collapse of stone retaining wall in Kourouklata village. (38.241797, 20.473677).
Stone masonry retaining wall failures supporting roadways were also identified on the road
between Lixouri and Argostoli. Out-of-plane collapse was recorded in two successive locations
following the 1st event with an estimated failure length of 10 m and 20 m, respectively (Figure
8.3.17a). These failures progressed following the 2nd event that also caused failure at an
additional, third location (Figure 8.3.2b). In contrast, the adjacent reinforced concrete sections
remained essentially intact.
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(a)
(b)
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5 m
(c)
(d)
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Figure 8.3.17. (a) Extensive failure of stone masonry retaining wall followed by road embankment settlement close to Atheras Village (38.293224°N, 20.45217°E) after 1st event; (b) failure at 3rd wall location after 2nd event with adjacent concrete sections undamaged; (c), (d), (e) failure details.
A case of a relatively short, 1.2-m high, wall is shown on Fig. 8.3.18 near Argostoli. Despite
its low height, this wall was damaged as a result of earthquake shaking. However, it is not
known which of the two events caused the failure.
Figure 8.3.18. Failure of a short masonry wall near Argostoli (38°10'50.76"N, 20°29'54.01"E).
Another example of masonry wall failure near Lixouri is shown on Figure 8.3.19. A
stone/masonry wall failure in a cemetery in Livadi village is shown on Figure 8.3.20 and two
retaining wall failures in the cemetery of Lixouri are shown on Figures 8.3.21 and 8.3.22.
Another small wall failure at the Theotokos Kipouraion Monastery is shown on Figure 8.3.23
and a few failures in Aghia Thekla village, as shown on Figures 8.3.24 to 8.3.27.
(e)
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Figure 8.3.19. Failure of masonry wall supporting roadway outside of Lixouri (38°12'21.05"N; 20°24'54.89"E).
Figure 8.3.20. (a) View of stone/masonry retaining wall failure at the cemetery of Livadi village. (b) Close-up photo showing rotation of the wall face and tension cracks in the backfill (GPS coordinates: 38.255833, 20.420833).
(a) (b)
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Figure 8.3.21. Collapsed retaining wall at cemetery of Lixouri with close up (b-c) side views (GPS coordinates: 38.192400, 20.438725); (d-e) top views (38.192433, 20.438725).
(a)
(b) (c)
(d) (e)
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Figure 8.3.22. Failure of a small retaining wall at the back yard of the Lixouri cemetery’s church (GPS coordinates: 38.192911, 20.438625).
Figure 8.3.23. Partially failed small retaining wall in the backyard of the Theotokos Kipouraion Monastery (38.203194, 20.348219); (b, c): View from the backyard: collapse of retaining wall marked with red circle. (38.203327, 20.347747).
(a)
(b) (c)
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Figure 8.3.24. Retaining wall collapse in front of the “new” Aghia Thekla church (GPS coordinates: 38.245202, 20.384422).
Figure 8.3.25. Damage of stone walls in Aghia Thekla village (GPS: 38.245202, 20.384422).
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Figure 8.3.26. The old Aghia Thekla church (GPS coordinates: 38.244894, 20.386097).
Figure 8.3.27. A small retaining wall failure at the old Aghia Thekla church cemetery (GPS coordinates: 38.244944, 20.386433).
Note that related structural damage to churches is presented extensively in Chapter 11 of
this report.
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CONCRETE RETAINING WALLS
A number of concrete walls (gravity or cantilever types) were damaged as a result of the
strong motions induced by the two earthquake events. An interesting case of a gravity wall that
was heavily damaged during the 2nd event, in the town of Chavriata, shown on Fig. 8.3.28. This
wall is located in the vicinity of the strong motion station that recorded a peak value of
horizontal ground acceleration PGA equal to 0.74 g. The lower part of the wall is 2.1 m tall
and the upper part has a height of 1.8 m. The two portions appear to have been built at different
times as there is a cold joint between them with no tie-in steel reinforcement. The upper portion
of the wall appears to have been simply pushed and toppled.
Figure 8.3.28. Failure of concrete retaining wall along a cold joint. The upper and lower portions of the wall appear to have been built at different times (38°11'0.07"N; 20°22'54.18"E); (a, b) side views; (c, d) top view with tensile cracks of soil surface at hill top where the strong motion station is located.
At the same location, another reinforced concrete wall with a length of approximately 250
m and a height ranging from 3.2 m to 3.9 m retains the main paved road of the town (Fig.
8.3.29). The axis of the wall is curved in plan and has a general East-West strike. The wall did
not show signs of distress. A long section of the road retained by the wall was cracked and
settled vertically by 5 to 15 cm and displaced horizontally by about 3 to 7 cm.
(a) (b)
(c) (d)
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Figure 8.3.29. Cracked pavement due to wall movement with retaining wall on the left. (38°10'57.83"N, 20°23'9.40"E).
A case of a distressed cantilever type retaining wall is shown on Figure 8.3.30. The wall is
located on the roadway between Havdata village and Lixouri. It is not known whether this wall
was damaged during the Event 1 or Event 2. The wall is retaining a backfill, forming the yard
of a car body shop and has variable height ranging from 0.66 m to 3.1 m. The portion of the
wall with the maximum height tilted outwards and the backfill moved laterally about 12 cm
and also settled, defining the sliding plane. Water drains were provided close to the base of the
wall.
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Figure 8.3.30. Tilted cantilever retaining wall of variable height on the roadway between Havdata and Lixouri. (38°12'21.05"N, 20°24'54.89"E).
CONCLUSIONS
There were few, if any, major retaining walls in the Cephalonia island. The main shocks of
the 2014 earthquake sequence induced several mechanisms of instability (sliding, tilting,
toppling, and fracture with out-of-plane collapse) to a large number of masonry earth retaining
walls located in the meioseismal area of the Paliki peninsula. Most of the failures were
associated with simple non-engineered walls, or walls that were part of a steep terrain and their
collapse was the inevitable consequence of slope failure. The same behavior was observed,
albeit to a much lesser degree, to concrete walls (gravity and cantilever type) subjected to
strong horizontal (and vertical) motions. Most of the observed damage to retaining walls was
caused by the strong ground shaking associated with the 2nd event of 2/3/14.
8.4 Landslides and Rock Falls INTRODUCTION
Landslides and rock falls were observed mainly in the Paliki Peninsula west of the
Argostoli Bay and along the coastal zones between the Argostoli area and Myrtos Bay. The
north and east part of the island is practically free of these effects (Figs. 8.4.1). This is in
accordance with general observations about seismic intensity, as derived from strong motion
recordings, cemetery data, building performance, liquefaction observations, etc., as presented
in the other sections of this report.
This section summarizes observations made by several reconnaissance teams, including
AUTH-LSDGEE, UPatras, ITSAK, DUTH, and NTUA, following the two major events in the
time period between February 8 and February 23, 2014. The areas investigated are shown in
Fig. 8.4.1a and cover the meioseismal area and beyond (see also Section 2.2 with map, names
and coordinates of towns). The reconnaissance teams tried to document and identify damage
patterns influenced by a variety of factors, including vulnerability of materials, topographic
features, presence of precarious rocks, proximity to source, near-fault earthquake directivity
and site effects. It appears that most of the affected area may have been located on the hanging
wall of the rupture (pending release of fault trace by seismologists).
Figure 8.4.1.a Locations investigated (AT: Mt. Ainos Thrust, AEF: Aghia Ephymia Fault).
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GEOLOGY ALONG THE INVESTIGATED PATHS
The western part of Cephalonia island is separated from the central part by the Mt. Ainos
thrust with a NNE–SSW direction. The central part of the island is split into a northern and
southern area by the Aghia Ephymia Fault with a NNW–SSE direction. Details on the
geology can be found in Chapter 6 of this report.
The path from Argostoli north to Aghios Ioannis (between the villages of Kourouklata
and Kontogourata), goes along Upper Cretaceous pelagic limestones. Between Kontogourata
and the coast of Aghia Kyriaki, the path goes along the mount Ainos thrust which consists of
successive zones of Oligocene limestones followed by well-bedded pelagic marls and marly
limestones, Eocene thick-bedded limestones covered by alluvial deposits or scree. Similar
geologic formations exist at the central slope of Myrtos bay, which is on the Aghia Ephymia
Fault, while adjacent slopes dipping southwards and northwards consist of cretaceous pelagic
limestones. The paths going through the rest of the Paliki Peninsula cross areas of
conglomeratic and brecciated limestones and near Lixouri, yellowish sand, sandstones, sandy
limestones and upwards blue marls, covered by sandstones and sandy marls. Figure 8.4.1a
shows all locations visited by the reconnaissance teams. Figures 8.4.1c through 8.4.1d show
the field investigation paths followed by the UPatras team.
Figure 8.4.1.b Cephalonia path on 2/8/14 (black), 2/9/14 (red) of Paliki Peninsula and Argostoli Bay
by UPatras team. Geographical distribution of rock falls (yellow points) and road embankment
settlements (blue points).
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Figure 8.4.1.c Cephalonia path on 2/8/14 (black), 2/9/14 (red) of Atheras (south of Paliki Peninsula)
and Myrtos Bay by UPatras team. Geographical distribution of rock falls (yellow points) and road
embankment settlements (blue points).
Figure 8.4.1.d Cephalonia path on 2/17/14 (green) on the eastern part of Cephalonia by UPatras team.
Geographical distribution of rock falls (yellow points).
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ROCK FAILURES – ROCK SLIDES
Along the paths in Figs. 8.4.1(b,c,d), the reconnaissance teams observed one major rock
fall with debris slide in steep cliffs (Fig. 8.4.4) and a major deep-seated bedrock slump in a
natural slope undercut by a road (Fig. 8.4.2). In addition, numerous minor rock falls were
spotted along the road cuts, ranging from simple block falls to more extended rock falls
within various types of limestones (blocky, fractured and/or weathered).
In total, over 30 rock falls were recorded in the Argostoli–Katochori–Myrtos Bay path,
over 10 in the western part of the Paliki Peninsula and a limited quantity (possibly only 2) in
the eastern part of the island (Fig. 8.4.1). Indicative cases of local rock slides in consolidated
red conglomerates formations were observed north of Argostoli Bay close to Kardakata
Village (38.280957°N, 20.445637°E) and along the road network connecting Argostoli and
Sami village (38.205687°N, 20.607155°E), inducing damage to the road (Figs. 8.4.5, 8.4.6).
In the same region of Argostoli bay, rock slides were also observed (38.287065°N,
20.448024°E) in cracked limestone formations (Fig. 8.4.7). These rock slides were
significantly magnified after the 2nd
event of 2/3/14.
Figure 8.4.2. Rock slope failure in limestone in Monastery of Theotokou Kipouraion (38.202517° N,
20.348083° E, (a) UPatras team, 2/9/14, (b) NTUA team, 2/10/14).
(a) (b)
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Figure 8.4.3. Numerous weathered rock landslides/rock falls along the shore near Monastery of
Theotokou Kipouraion. (38.203327° N, 20.347747° E, NTUA team, 2/10/14)
Figure 8.4.4. Rock fall with debris slide in steep cliffs in Platia Ammos beach (38.213883°N,
20.353017° E, UPatras team, 2/9/14).
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Figure 8.4.5. Rock failure of conglomeratic or breciatic limestone on a cut slope between Moussata
& Vlachata villages on the Poros-Argostoli road axis (38.126874° N, 20.616777° E, DUTh,
2/22/14).
Figure 8.4.6. Rock slides in red consolidated conglomerate formations recorded at (a) Northern part
of Argostoli bay close to Kardakata Village (38.280957°N, 20.445637°E) and (b) road network
between Argostoli and Sami village (38.205687° N, 20.607155° E, ITSAK team, 1/28/14).
Figure 8.4.7. Rock slides in cracked limestone formations recorded at Northern part of Argostoli bay
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following the (a) 1st event (38.287065° N, 20.448024° E) and (b) 2
nd event (38.287018° N,
20.448027° E). Photos by ITSAK team on 1/28/14(a) and 2/10/14(b).
Many shallow rock failures, both minor and major, were observed along the steep cliffs
lining the west coast of Paliki (Figure 8.4.8). The more pronounced rock failures seemed to
be several disaggregated slides with debris flow observed at the Petani shoreline
(38.260941°N, 20.377410°E). One of these slides resulted in the closure of the road towards
the seashore. It should be mentioned that an indeterminate number of the high steep cliffs
above beautiful white beaches on the west side of Paliki are in a state near limit equilibrium,
most probably due to shallow decompression joints parallel to their slope and weathering.
Failure of these slopes followed by debris slides does not require intense seismic
accelerations, as opposed to slides - such as those shown on Figures 8.4.2 and 8.4.4 - which
indicate the action of intense accelerations.
Figure 8.4.8. Disaggregated slides with debris flow observed at the Petani shoreline (38.261705° N,
20.380166° E). Photo by NTUA team, 2/9/14.
A shallow rock slide with debris flow of weathered and severely fragmented limestone
was observed (Figure 8.4.9) on the local road of Argostoli between Kourouklata and
Kontogourata village (38.251408°N, 20.466813°E). The local road from Kardakata to Zola
village (en route to Aghia Kyriaki Bay) suffered numerous rock planar slides along the
limestone’s bedding. On the right side of the road, the orientation on the road cuts favored
rock planar sliding (Figure 8.4.10b), while on the left side only occasional wedge failures
emerged (Figure 8.4.10a) and no rock toppling or rock fragment detachments were observed.
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Figure 8.4.9. A shallow rock slide of a weathered and fragmented limestone with debris flow
(38.251408° N, 20.466813° E, (a) Date of picture taken by DUTh team is 2/22/14, and (b) by
UPatras team is 2/8/14) along the local road from Kourouklata to Kontogourata).
Figure 8.4.10. Rock failures (mostly planar slides along limestone’s bedding and only occasionally
wedge failures) along road cuts on the way from Kardakata to Zola village in Aghia Kyriaki bay
area (from 38.287181° N, 20.457548° E to 38.310356° N, 20.469258° E, DUTH team, 2/22/14).
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More important seemed to be the rock slope failures in Myrtos Bay, where four
important shallow disaggregated slides with debris flow occurred at the north and south part
of the Bay. On the east slope, two large blocks from the overtopping limestones rolled down
westwards on soil-topped slopes, causing total destruction of the descending road at three
points (38.337833°N, 20.532317°E). New movements were observed at the crest of the
slope on old slide mobilization planes, likely due to blocky limestone overlaying softer
material. Figure 8.4.11 shows the Myrtos bay area with debris flows at the North part
(center), a wedge type failure of crashed material (top left), two major rock blocks that
rolled down (bottom right) and the access road destruction from the 2nd
rock block (top
right). The arrows indicate the location of the details mentioned. Roll paths of the two large
rock blocks are shown in Fig. 8.4.11. Interestingly, cemetery monuments at a small distance
(~700 m) from Myrtos Bay had no damage at all. Similar shallow debris flows were
observed in various locations along the steep cliffs on the west coast of Paliki. One such
shallow debris flow was observed in Platia Ammos (Fig. 8.4.4), north of the Theotokou
Kipouraion Monastery.
Figure 8.4.11. Northern cliffs and eastern slopes of Myrtos Bay. Major wedge failure, shallow
rockslides and raveling; detachment and rolling down of the two major rock blocks with the
associated road pavement damage (38.337833° N, 20.532317° E, UPatras, 2/10/14).
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Figure 8.4.12. Roll paths A and B of the two rock blocks of estimated volume of 500 m
3 each
at Myrtos Bay (38.337833°N, 20.532317°E, ITSAK team, 2/19/14).
Rock falls were observed in Atheras village (38.317350o N, 20.418358
o E) at the
northern part of the Paliki peninsula, where 7 or 8 limestone boulders ranging between 0.5
to 2.0 m3 in volume were detected in the aforementioned village. In all these rock falls, no
human injuries or deaths were reported, whereas some cases of property damage were
recorded. For instance, the roof of a house, was partially destroyed by a boulder of almost 2
m3 (Figure 8.4.13). The potential trajectory of the rolling and bouncing boulder that was
detached from the upward mountain slope is roughly presented in Figure 8.4.13. In the same
figure, the tracks of points where the bouncing boulder struck are also shown: the 1st and the
3rd
strikes are located on limestone retaining walls.
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Figure 8.4.13. Possible trajectory of a limestone boulder of about 2 m3 that rolled over a natural slope
and bounced at least 3 times, passing through a tile roof of a house in Athera village. Tracks of
striking points where boulder bounced also shown (38.317365° N, 20.418548° E, DUTh team,
2/22/14).
Figure 8.4.14. Shoreline of Xi area (from 38.159537° N, 20.410148° E to 38.160405° N, 20.413083°
E) south of the Paliki peninsula where an extended slide (almost 250 m long) of a sandy marl
escarpment was observed (ITSAK team, 02/19/2014).
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An extended rock slope-type failure (almost 250 m long) of a sandy marl escarpment was
observed in the Xi area shoreline (from 38.159537° N, 20.410148° E to 38.160405° N,
20.413083° E) south of the Paliki peninsula (Fig. 8.4.14). Along the local road from Sami to
Poros, only two rock slides were observed with limited debris flow (Figs. 8.4.15 and 8.4.16).
Figure 8.4.15. Rock slope failure in road cut with gabions in fractured/weathered limestone.
Detached rock block crossed the road (eastern part of island: 38°11'33.51"N, 20°40'39.04"E, UPatras,
2/19/14).
Figure 8.4.16. Rock slope failure in a road cut with gabions in weathered/fractured limestones
(eastern part of island, 38°11'52.99"N, 20°40'21.80"E, UPatras team, 2/19/14).
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EARTH LANDSLIDES
Only two major earth landslides were observed; the first one, in the Soulari area, is
more developed with an important crack formation at the crest of the slope (Fig. 8.4.17).
According to locals, the specific landslide presented signs of instability due to rainfalls prior
to the earthquakes and may have existed for a long time. Thus, the slope was likely near limit
equilibrium and the observed patterns and displacements (~ 2.5 m) were related to the
earthquakes events reactivating an older slide plane. The second is an extended incipient
failure involving road embankment settlement and local stone retaining walls destruction
(Figs. 8.4.18, 19). The wider area of that slope was creeping even before the earthquake, and
had forced the construction of a heavy retaining wall and pavement repairs.
Figure 8.4.17. Major earth landslide in Soulari (38°11'5.66"N, 20°24'57.82"E, UPatras, 2/17/14.
Few other minor cases of slope movement were observed in the Soulari area. The first
case of mild slope movements in soils was observed at an isolated 15m high clayey hill in the
vicinity of the village of Soulari at the southern part of the Paliki Peninsula (Figure 8.4.20).
Measurements at the crest of the slope showed horizontal displacement of 15 cm towards the
East, and vertical displacement (settlement) of approximately 8 cm. Of interest in this case is
the fact that the 2-story reinforced concrete building adjacent to the slide suffered no damage
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(not even cracks in plaster covering the masonry infills). Another example of a small
landslide in a stiff-clayey slope outside of Soulari village is presented in Figure 8.4.21.
Figure 8.4.18. Plane view of the incipient landslide failure.
Figure 8.4.19. Area showing signs of incipient earth landslide failure. (a) Cracks on upper road
pavement (UPatras) and (b) stone retaining walls destruction after the 1st and 2
nd events (ITSAK), and
soil displacements at the toe (coordinates 38.293224°N, 20.45217°E, date 2/8/14).
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Figure 8.4.20. Crest of circular type of slope movement on a 15 m high hill near Soulari village
(38°11'19.73"N, 20°24'45.10"E), with slippage towards the East direction, (date 9/2/14).
Figure 8.4.21. Small landslides in stiff-clayey slopes, 400 m outside Soulari village. (38.184444° N,
20.411388° E, NTUA team, 2/10/14).
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ROAD EMBANKMENT VERTICAL DISPLACEMENTS
A total of 34 vertical displacements at the shoulder of road embankments were observed
mainly at the central part of the Paliki Peninsula. Figure 8.4.22 shows such major failure
recorded after the two events, followed by extensive cracking of the road in Havdata
(38.2028°N, 20.40445°E).
Figure 8.4.22. Road embankment settlement near bridge in Havdata (38.2028°N, 20.40445°E,
UPatras team, 2/9/14).
In Figure 8.4.22, the details show the kind and the extent of vertical displacements of the
embankment on both sides of a concrete bridge extending over an approximately 8 m deep
creek. The total length of the settled embankment was 32 m. Figure 8.4.23 shows the road
embankment settlement and surface cracks in the village of Chavriata near the south of the
Paliki Peninsula.
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Extensive road cracking and road embankment failure (Figure 8.4.24) were also observed
on the road network connecting Chavriata and Vouni villages in the south part of the Paliki
peninsula (38.287065°N, 20.448024°E) after the two major events.
Figure 8.4.23. Road embankment settlement in Chavriata (38.182733°N, 20.384067°E, date 2/9/14).
Measurements by UPatras team members Eva Agapaki, Elpida Katsiveli, and Costas
Papantonopoulos.
Figure 8.4.24. Road network connecting Chavriata and Vouni villages at the south part of the Paliki
peninsula (38.17856° N, 20.40081° E); extensive road cracking and road embankment failure
observed, respectively, after the: (a) 1st and (b) 2
nd events. Photos by ITSAK team on 1/28/14 (a) and
2/5/14 (b).
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CONCLUSIONS
Extended rockfalls, mostly within various types of limestones, and earthslides occurred in
the Paliki peninsula, many of which induced road damage, after the two major earthquake
events on 1/26/14 and 2/3/14. Important rock slides were observed in the coastal zone from
the Argostoli area to Myrtos Bay (with the most extensive rock slides noted in Myrtos Bay)
and in the steep cliffs west of the Paliki peninsula (Platia Ammos, Monastery of Theotokou
Kipouraion). Minor damage due to rock slides was observed in the eastern part of the island.
Earth landslides were generally limited with minor damage, with only two exceptional
landslides (the two indicative cases shown in this chapter), one in Soulari (the formation of
which may have preexisted) and the other in Chavriata, which resulted in extensive road
embankment settlements.
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8.5 Bridges INTRODUCTION
As in all islands of the Ionian sea of Greece, the bridge inventory of Cephalonia includes
mostly single, short-span reinforced concrete bridges. Notable exception to this rule is the
historic (1830) multi-span stone Debosset bridge, discussed in this section. Overall, bridges on
the island responded well to two main seismic events and their aftershocks. None of the bridges
collapsed or suffered severe enough damage to interrupt traffic. Among several tens of bridges
inspected (Fig. 8.5.1), only one suffered relatively significant damage on the approach
embankments, resulting to partial traffic interruption.
Figure 8.5.1 Locations of bridges inspected during reconnaissance and described in this section; the figures referenced correspond to the figure numbers of this section (for example, Figure 2 stands for Figure 8.5.2).
2‐4
!
5‐6
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HAVDATA BRIDGE
Severe damage was observed in the reinforced concrete Havdata bridge (38°12'10.30"N,
20°24'16.05"E), only one out of the several bridges inspected during reconnaissance. This
bridge is a reinforced concrete creek overpass over the asphalt country road, heading west from
Lixouri city to Havdata village (approximately 3.6 km from Lixouri and 2 km from Havdata).
It is 4-m long, spanning a 6-m deep creek, and is connected to the asphalt country road by 12-
m long access embankments on either side.
Fig. 8.5.2(a) shows longitudinal pavement cracking and severe settlement at the location
where the western access embankment adjoins the reinforced concrete bridge. Fig. 8.5.2(b)
shows the much less settled pavement at the respective location of the eastern access
embankment.
Settlements occurred at the southern side of the bridge, i.e., towards the downstream of the
overpassed creek. We observed significant differential settlement of neighboring access
embankments: up to 30 cm at the western embankment, versus a maximum of 8 cm at its
eastern counterpart. Settlements diminish at a transverse distance of 2.5 m from the
downstream side of the bridge (i.e., at the centerline of the road), whereas in the longitudinal
direction they essentially diminish at the end of the access embankments (almost 12 m from
the overpass edges).
Figure 8.5.2. Havdata bridge (38°12'10.30"N, 20°24'16.05"E): (a) western access embankment and (b) eastern access embankment.
Hence, settlements and pavement cracks appeared all along the embankments, reaching
maximum values at the connection to the bridge. The different settlement response in the two
access embankments can be attributed to the observation that the (southern) retaining wall of
the western embankment suffered downstream outward displacement of a maximum of 19 cm,
(a) (b)
30 cm 8 cm
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at the location where it adjoins (cold joint) the bridge (Fig. 8.5.3), whereas there was no
dislocation of its counterpart at the eastern embankment.
Figure 8.5.3. Havdata bridge (38°12'10.30"N, 20°24'16.05"E): Side view of outward (downstream) displacement of southern retaining wall of western access embankment.
From a structural point of view, the reinforced concrete Havdata bridge consisted of the
pier (with width equal to that of the deck) and the deck, which included a transverse beam. The
deck-beam section that rested on top of the pier has undergone small permanent drift, at least
in the southern embankment shown in Fig. 8.5.4. Whether there are steel studs between the two
bridge sections is unknown, but there is definitely no bearing (rubber or otherwise). Also, there
could have been some pounding between the retaining wall and the deck-pier and pier sections,
since the edges of the reinforced concrete sections had been chipped off.
Figure 8.5.4. Havdata bridge (38°12'10.30"N, 20°24'16.05"E). Side view of connection of southern pier to deck-beam sections of the bridge.
deckwall
pier
deck‐beam
retaining wall
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DEBOSSET BRIDGE
The performance of the Debosset bridge following the two main events is described in this
report due to the bridge’s landmark status and history of retrofit. Originally constructed in
1830, the historic multi-span Debosset stone bridge (38°10'26.25"N, 20°29'45.59"E) connects
the shorelines of Argostoli and Drapano at the southern side of Argostoli bay. It is comprised
by successive stone arches founded on stiff block-type stone piers. The bridge has a total length
of 750 m with height that varies between 2 to 4 m along its longitudinal axis (Fig. 8.5.5).
Figure 8.5.5. Debosset bridge connecting the Drapano and Argostoli shorelines (GPS coordinates 38°10'26.25"N, 20°29'45.59"E). Photo taken prior to the 1953 earthquakes (Poulaki-Katevati, 2009).
Following the severe Ms = 7.2 earthquake of 1953, the bridge sustained extensive damages,
inducing differential settlement of the deck and out-of-plane collapse of the arch walls and
filling material. Major parts of the bridge were reconstructed in the period 1960-70, using
reinforced concrete while maintaining the original architectural pattern, but modifying
substantially the material homogeneity and structural stiffness.
In 2005, a multidisciplinary research project for the seismic assessment and restoration of
the Debosset bridge was undertaken by the Laboratory of Soil Mechanics, Foundation and
Geotechnical Earthquake Engineering (LSMFGEE) of AUTH, under the auspices of the Greek
Ministry of Culture (Directorate for the Restoration of Byzantine and Post-byzantine
Monuments).
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As described in Pitilakis et al. (2006) and Rovithis & Pitilakis (2011), an extensive
subsurface investigation program was conducted along the bridge, including borings with
Standard Penetration Testing (SPT), and geophysical testing using the Crosshole Seismic (CS)
and Microtremor array methods. Locations of the testing and geologic section showing soil
stratigraphy and measurements of shear wave velocities, Vs , are presented Fig. 8.5.6. The
regional sandstone encountered at a depth of about 35 m below grade was characterized as
bedrock with Vs of 1 km/s, overlaid by soft surface silty clay deposit with Vs ranging between
140 and 170 m/s.
Figure 8.5.6 (a) Geotechnical and geophysical test locations along Debosset bridge, and (b) geologic section revealing soil profile along the line B1-B2 shown in (a) (sketch created by Adam Dyer of MRCE based on Pitilakis et al., 2006).
The 2005 bridge rehabilitation included use of micropile foundations to improve the soft
clayey foundation soil and incorporation of lateral tendons to increase the transverse strength
of the bridge, all completed before the 2014 earthquakes. Architectural restoration of the bridge
facades was also partially completed at the time of structural rehabilitation (Fig. 8.5.7b). The
rehabilitated Debosset bridge was inspected by ITSAK and AUTH-LSMFGEE reconnaissance
teams after both major events, during the periods of January 27-30, and February 10-12 and
18-20 of 2014. The inspection revealed no damage or visible defects on the bridge structure,
and overall satisfactory seismic performance, despite the high accelerations experienced in this
site, indicating the benefits of the seismic rehabilitation work.
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Figure 8.5.7. (a) Debosset bridge (38°10'26.25"N, 20°29'45.59"E); (b) Rehabilitated bridge with no observed damage following the major events of 2014; (c) Multi-drum obelisk (Kolona) monument intact after the 1st event; and (d) Toppling of upper drum of the obelisk induced by the 2nd event.
Figure 8.5.8. Obelisk “Kolona” monument (GPS coordinates 38°10'26.25"N, 20°29'45.59"E) in early 1900’s sketch (Poulaki-Katevati, 2009). The upper drum toppled after the 2nd 2014 event (Fig. 8.5.7d).
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The only damage within the opening of the bridge was observed at the multi-drum stone
obelisk monument locally known as “Kolona.” The monument was erected in 1813 in
appreciation of Great Britain by the local Cephalonian government (see 1900’s sketch of Fig.
8.5.8, modified from Poulaki-Katevati, 2009). While the monument remained intact after the
1st event of January 24, 2014, its upper drum toppled following the 2nd event of February 3,
2014 (Fig. 8.5.7d).
The quay wall adjacent to the Debosset bridge suffered permanent horizontal displacement
of 10 cm towards the shoreline with an approximate backfill settlement of 15 cm measured at
following the 1st event (Fig. 8.5.9a). The observed lateral movement of the quay wall and
settlement of the backfill were further increased, almost doubled at some points, following the
2nd event (Fig. 8.5.9b).
Figure 8.5.9. Observed failures adjacent to the Debosset bridge: permanent lateral displacement of the quay wall and settlement of the backfill induced by: (a) 1st event, and (b) 2nd event.
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8.6 Embankments and Landfills INTRODUCTION
This section is divided into two parts; the first part describes effects of the first and the
second event on road embankments, and the second part describes both event’s effects on other
types of embankments such as landfills and reservoirs. Overall, road embankments performed
relatively well, with very few instances of severe and moderate damage leading to complete or
partial obstruction of traffic. The majority of embankments suffered minor damage, most
frequently in the form of asphalt cracking near the embankment edges due to either slope
stability or masonry retaining wall failures. Other types of embankments such as landfills and
dams performed remarkably well with no reported damage, although arguably the former were
of relatively small height, and the latter were located at large epicentral distance from both
events. In the ensuing, we use the term “severe” damage for road embankment performance
that completely interrupted traffic; and term “moderate” damage for road embankment
performance that resulted in traffic obstruction across half or more of the road width.
ROAD EMBANKMENTS
The road embankment inventory of Cephalonia includes many (rather short) road
embankments. This characteristic design stems from the intense topography, which usually
prevents the construction of asphalt roads by mere cuts into steepened slopes. Typically, these
roadway embankments are retained by masonry walls (typically made of natural limestone)
and, to a lesser extent, by reinforced concrete walls. Figure 8.6.1 shows locations of road
embankments inspected during reconnaissance surveys. Overall, the response of road
embankments to two main events and their aftershocks was satisfactory. The term
“satisfactory” reflects a performance of partial roadway traffic operation immediately
following the two events since the road embankments damage was in general far from collapse.
Some notable exceptions with severe damage observations are described in this section.
Locations with severe damage
We use the term “severe” damage for road embankment performance that completely
interrupted traffic. Such locations were very few, including: (a) destruction (not only blockage)
of the access road to Myrtos beach due to major rockfalls (38°20'16.20"N, 20°31'56.34"E); see
also Section 8.4, and (b) extensive cracking of the embankment that affected the whole width
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of the road connecting the Chavriata and Vouni villages, at two neighboring locations depicted
in Figs. 8.6.2 and 8.6.3, respectively. These locations are referred to as Locations A and B, for
lack of a more descriptive distinction between them.
Figure 8.6.1. Locations of road embankments inspected during reconnaissance and described in this section. Figures referenced correspond to section figure numbers (e.g., Fig. 2 stands for Fig. 8.6.2).
Figure 8.6.2 shows the road embankment at location A (38°10'42.84"N, 20°24'2.96"E)
after: (a) the 1st event and (b) the 2nd event. It appears that initiation of slope stability failure
after the 1st event set the ground for failure of the paved road observed after the 2nd event.
Similarly, severe damage was observed at Location B along the road connecting Chavriata and
Vouni villages (38°10'39.79"N, 20°23'50.90"E), just 320 m away from Location A (Fig. 8.6.3).
The severe damage at Location B could be attributed to failure or total collapse of the masonry
walls on both the SE and NW sides of the embankment. The estimated height of the retaining
walls ranged from 6 to 8 m. These wall failures induced failures on both sides of the road
embankment. Intensive horizontal cracks along the roadway, 20 to 80 m in length, with
horizontal and vertical displacements from 5 to 30 cm were observed. Interestingly, no damage
was observed at an adjacent reinforced concrete retaining wall.
2
3
7 & 8
10 9
6
4 & 5
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Figure 8.6.2. Location A (38°10'42.84"N, 20°24'2.96"E) on the road connecting the Chavriata and Vouni villages. (a) Circular type of sliding observed after the 1st event. (b) Embankment failure that affected the whole width of the road after the 2nd event.
Figure 8.6.3. Location B (38°10'39.79"N, 20°23'50.90"E) on the road connecting the Chavriata and Vouni villages. Severe road embankment damage was observed. Photos taken after the 2nd event.
The investigators noted that the road embankment bridges two opposite hills, where a mild
natural slope (estimated 10o to 15o) trends towards the NW direction. The geomorphology, in
(a) (b)
7‐15 cm30 cm
L = 75 ‐ 85 m
20 ‐ 25 cm
25 ‐ 30 cm
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conjunction with the damage concentration at the embankments, may be indicative of
topographic amplification of ground motion at the site, although more evidence is necessary
to support this hypothesis.
Locations with moderate damage
We use the term “moderate” damage for road embankment performance that resulted in
traffic obstruction across half or more of the road width. There were quite a few such locations
on the island. Moderate damage typically involves major longitudinal cracks and large
settlements on the asphalt pavement, as a result of large downslope displacements of sliding
masses within the embankment material, or (for relatively high embankments) the total
collapse of typically old masonry retaining walls mad of natural local limestone. These
intermediate damages led local authorities to close down half the width of the road, such that
the roads remained only partially open but traffic was maintained.
An example of moderate roadway embankment damage location was recorded along the
main asphalt road connecting Argostoli to Lixouri, and to the NW of the village of Kardakata.
Figure 8.6.4a shows the collapsed masonry wall which had supported the road embankment,
as seen from the downhill side. Figure 8.6.4b shows the effects on the pavement of a similarly
collapsed masonry wall for the same road embankment (just 160 m apart).
Figure 8.6.4. Off-Kardakata road embankments at an inter-distance of 160 m after 2nd event: a) masonry wall collapse in NS direction (38°17'34.61"N, 20°27'8.16"E), b) masonry wall collapse in EW direction (38°17'30.81"N, 20°27'11.80"E).
The GEER investigators noted that the former wall collapsed in an NS direction, while the
latter wall collapsed in an EW direction, both following the downhill direction of the surface
topography. The wall section in between the two failed walls suffered no damage, possibly due
to height or construction quality differences. Figure 8.6.5 compares the state of the latter failed
(a)
(b)
(b)
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masonry wall (that failed in an EW direction) after the 1st event (1-26-14) in subplot (a) and
after the 2nd event (2-3-14) in subplot (b). Observe in this figure that the 2nd event increased
considerably the length of the failed masonry wall at this location, and also deteriorated the
state of the road embankment just uphill from the failed masonry wall section. Just 30 m up
the road from the failed masonry wall section (Figs 8.6.4b and 8.6.5), the same road
embankment was retained satisfactorily by reinforced concrete walls that suffered no damage
and practically zero displacement (the undamaged reinforced concrete wall can be observed to
the right of the failed masonry wall section in Fig. 8.6.5b).
Figure 8.6.5. Overview of the broader area of the off-Kardakata road embankment failure of Figure 8.6.3b (38°17'30.81"N, 20°27'11.80"E): a) after the 1st event and, b) after the 2nd event.
Moderate damage also occurred at road embankments on the Paliki peninsula. Pertinent
examples include the excessive settlements (on the order of 25 cm) in the access embankments
of the (so-called) Havdata bridge, mainly due to the outward movement of the reinforced
concrete wall adjoining the bridge pier (at: 38°12'10.30"N, 20°24'16.05"E, see Section 8.5).
Similar damage was observed as cracks and settlements in the asphalt road (at: 38°14'17.17"N,
20°25'44.30"E) joining the Aghios Dimitrios and Livadi villages (Fig. 8.6.6). Both examples are
located in areas where several reinforced concrete buildings suffered significant damage (see
Section 11). Figure 8.6.6 shows the pavement cracks and the embankment settlements after the
1st (Fig. 8.6.6a) and the after the 2nd event (Fig. 8.6.6b).
(a) (b)
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Figure 8.6.6. Cracks and settlements on the road embankment between Aghios Dimitrios and Livadi villages (38°14'17.17"N, 20°25'44.30"E): (a) after the 1st (left) and (b) the 2nd (right) event.
Figure 8.6.7 presents the large downslope displacement of a circular sliding mass in clayey
soil that affected a country road embankment in the vicinity (north) of Soularoi village in Paliki
peninsula. The sliding occurred in an approximately NS direction, and the maximum vertical
settlement of the pavement was on the order of 40 cm.
Figure 8.6.7. North of Soularoi road embankment sliding, as viewed from the pavement (38°11'21.51"N, 20°24'45.80"E).
≈ 40 cm
(a) (b)
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Figure 8.6.8 presents a road embankment failure on the local road axis from Soularoi going
south towards Megas Lakkos (southeastern part of Paliki peninsula) at a site called Xontiches
(38°10'43.69"N, 20°25'13.87"E). This road embankment failure is the larger among others of
less importance along this road. The damaged embankment is roughly 5 to 6 m tall, with slope
inclination estimated at (Vertical to Horizontal) V:H = 2:3. The failure presents as longitudinal
horse shoe shaped tensile crack almost 50 m long with horizontal displacements of 30 to 35
cm and vertical displacements from 40 to 50 cm near the central part (around 15 m) and
significantly less movement close to the failure edges (Figure 8.6.8). Damage could be
attributed to poor compaction of the embankment soil.
Figure 8.6.8. South of Soularoi road embankment failure due to slope sliding (38°10'43.69"N, 20°25'13.87"E).
Locations with minor damage
In addition to the moderately and severely damaged embankments described above, there
were numerous locations where the road embankments suffered minor longitudinal cracks and
small settlements of the asphalt pavement; several of these embankments were found on the
Paliki peninsula in western Cephalonia and along the eastern leg of the main asphalt road
connecting Argostoli to Lixouri, where the topography is steep. These cracks appear to be due
to small downslope displacements of shallow surficial sliding masses within the embankment
material, or the partial collapse of (typically old) masonry walls made of limestone. In many
cases, the masonry walls failure left the pavement cantilevered.
Although these roads remained open to traffic, local authorities use road safety cones and
“do not cross” lines to locally divert traffic. An example of typical minor road embankment
≈ 50 cm
≈ 40 cm
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damage was observed on the eastern leg of the main asphalt road connecting Argostoli to
Lixouri, just north of Katochori village (38°17'8.28"N, 20°27'8.25"E) and is presented in
Figure 8.6.9. The GEER investigators observed that pavement cracks affected just the edge of
the embankment material, and allowed traffic in almost the full width of the road.
Figure 8.6.9. Pavement cracks and settlement at the edge of the road embankment located at 38°17'8.28"N, 20°27'8.25"E close to Katochori village. Photo was taken after the 1st event.
A typical example of minor damage involving a masonry wall was observed on the eastern
leg of the main asphalt road connecting Argostoli to Lixouri at the village of Kourouklata in
the north of the island (Fig. 8.6.10). In particular, Fig. 8.6.10a shows the collapsed masonry
wall in the foreground, while it also shows in the background, another similar (partial) collapse
at a higher altitude on the same winding road, whose detail is presented in Fig. 8.6.10b. Both
of the two collapses occurred along the NS direction (moving downslope towards the south),
and neighboring locations showed no damage, possibly due to height or construction quality
differences. Similar minor damage was observed in this area (e.g., at 38°14'26.29"N,
20°28'35.14"E), where this type of road embankment construction is common.
Minor damage was observed in the mountainous unpaved road from Kourouklata to
Kontogourata, just uphill from the asphalt road joining Argostoli to Lixouri, between
38°14'19.81"N, 20°28'7.77"E and 38°14'48.76"N, 20°27'54.79"E in a direction almost parallel
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to NS axis. At this location, intense longitudinal cracks with mean width 2 to 3 cm were
observed along the western edge of the unpaved (dirt) road. The entire cross section of the
unpaved road is on a cut and the depth of the displaced material at the edge of the road was
very shallow. Similar minor damage to road embankments was observed on the road
connecting Lixouri to Havdata, at 38°12'21.05"N, 20°24'54.89"E). In addition, a considerable
number of minor to intermediate road embankment damage was observed on the local road
from Mantzavinata village to Xi beach, in the south part of the Paliki peninsula.
Figure 8.6.10. Kourouklata road embankments: a) lower altitude masonry wall collapse (38°14'23.77"N, 20°28'30.29"E), b) higher altitude masonry wall collapse (38°14'28.20"N, 20°28'24.87"E) (also visible in a, is the failed bell tower of Kourouklata.)
Few road embankments supported by reinforced concrete retaining walls experienced
minor damage. Damages consist of longitudinal cracks and settlements (on the order of a few
cm, at most) near the displaced wall. Similar relatively good and easily repairable road
embankment behavior was observed on the Chavriata main road (38°10'57.84"N,
20°23'2.64"E, but also 38°10'57.52"N, 20°23'13.61"E), and the Kourouklata church plaza, at
least at the locations where the wall was not of masonry-type (38°14'31.72"N, 20°28'25.40"E).
Other (non-roadway) types of embankments did not suffer damage. Among those, the short
embankments retaining the reservoirs at Aghia Eirini in eastern Cephalonia (38°07'58.44"N,
20°45'20.13"E) suffered no damage mainly due to their large distance from the epicenter.
LANDFILLS
Two landfills, located next to each other as shown on Fig. 8.6.11, were investigated as part
of the reconnaissance studies. The old unlined landfill (38°18'35.26"N, 20°26'24.86"E) is now
closed. The new lined landfill (38°18'34.82"N, 20°26'35.17"E) is currently receiving
Municipal Solid Waste generated in the islands of Cephalonia and Ithaki.
(a) (b)
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Figure 8.6.11. The location of the two adjacent Cephalonia landfills (38°10'57.52"N, 20°23'13.61"E).
The old landfill was in operation from 1981 until approximately 2004 when disposal
operations switched to the new, lined landfill. Although the containment system details of the
new landfill are not known, it appears to be a composite system of a compacted clay liner and
a geomembrane liner overlain by a gravel layer used as leachate collection and removal system.
Fig. 8.6.12a presents the presently well vegetated old landfill and Fig. 8.6.12b shows the
new landfill. According to the landfill operator and an on-site GEER visit on 2/10/14, the
landfills performed well with no cracking, displacements or any other damage observed
following the earthquakes. However, the investigators note that the height of the lined landfill
was on the order of 10 m (30 ft), which, compared to typical modern landfills of height 60 m
(200 ft) or more, is relatively short and thus likely to be resilient against slope stability failures.
Figure 8.6.12. View of the (a) unlined landfill (vegetated, in the background; 38°18'33.15"N, 20°26'30.44"E) and (b) lined landfill (38°18'36.94"N, 20°26'29.02"E).
(a) (b)
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8.7 Settlement and Soil-Structure Interaction
INTRODUCTION
Dynamic Soil-Structure Interaction (SSI) phenomena are difficult to identify in post-
earthquake investigations, since the associated kinematic and inertial effects that develop in
the foundation and the superstructure are inherent in the structural response and cannot be
separated from the observed residual deformations without performing detailed analyses. In
presence of soil liquefaction (often manifested at the soil surface) and other soil softening
phenomena, significant SSI effects can develop due to compliance of the liquefied/softened
material. The results presented in this section summarize observations from 10 structures
documented by AUTH, UPATRAS, UTH and MRCE reconnaissance teams regarding
performance of structures with reference to settlements and SSI effects. The data were gathered
from two investigations during the periods 8-10 and 18-19 of February 2014. Additional
detailed documented cases of structural damage are presented in the Chapter 11.
Figure 8.7.1. Locations of the 10 structures inspected during reconnaissance for SSI and settlement
effects. Additional cases documenting structural damage are presented in the Chapter 11.
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A number of structures in the meioseismal area, especially in Lixouri, experienced vertical
and horizontal permanent displacements. Most of the damage was concentrated near the
coastline, directly inland from the port of Lixouri, built on reclaimed land generated by
demolition material from the 1953 earthquake that spread laterally. Horizontal displacements
were recorded with emphasis on the first row of buildings adjacent and parallel to the port. In
many cases, it appears that the ground surrounding the structure has moved, while the structure
has remained in place, especially for pile-supported structures.
In general, structures in this area rocked, punched through, tilted, settled and displaced.
Relative permanent displacements between structures and the surrounding ground were less
than 3 cm. Lack of sand boil observation and displacement patterns suggest that liquefaction
did not occur and the structures in the first row of buildings next to the port may have been
affected by lateral spreading or differential displacement of the uncontrolled fill that reclaimed
the sea. The significant rainfall in the days preceding the reconnaissance may have erased
evidence that could shed some light in this aspect. Locals refer to “clayey soils” beneath the
structures that may indicate phenomena of cyclic softening due to seismic excitation. In some
other cases, dynamic densification seems to be the reason for ground failure. At the moment,
there is no definite conclusion for the reason behind ground failure at the port of Lixouri.
Indicative examples of permanent displacement are presented in this section.
CASE 1: 3-STORY STRUCTURE AT CORNER OF NESTOROS &
MEGALOU ALEXANDROU STREETS (38°11'45.50''N, 20°26'18.84''E)
The pavement surrounding the 3-story residential structure at the corner of Nestoros &
Megalou Alexandrou Streets (GPS Coordinates 38°11'45.50''N, 20°26'18.84''E ), as well as the
structure’s porch appear to have settled without causing damage to the remaining structure
(Fig. 8.7.1). Measured settlements were 11 cm on the SE corner, 1 cm in the southwest corner,
and 8.5 cm in the NW corner of the porch.
CASE 2: 2-STORY STRUCTURE AT THE CORNER OF MARATHONOS &
DIGENI LASKARATOU STREETS (38°12'7.47''N, 20°26'12.99''E)
The 2-story residential building (Fig. 8.7.2) at the corner of Marathonos and Digeni
Laskaratou Streets (GPS Coordinates 38°12'7.47''N, 20°26'12.99''E) had no obvious signs of
cracking due to differential settlements. The reconnaissance teams consider this to be a typical
case of buildings with no obvious settlement-related structural damage.
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Figure 8.7.2. Case 1: 3-story structure at the corner of Nestoros and Megalou Alexandrou Streets (GPS
Coordinates 38°11’45.50”N, 20°26’18.84”E, 2/18/2014).
Figure 8.7.3.Typical 2-story building with no damages due to settlements. The pavement suffered
significant displacements (GPS Coordinates: 38°12’7.47”N, 20°26’12.99”E, 2/18/14).
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However, in the particular structure of Fig. 8.7.2, the pavements in the perimeter subsided,
most likely due to lack of compaction or uncontrolled nature of the subsurface material, as this
area is built on reclaimed land generated by debris of the 1953 earthquake. The unusually
shaped pipes deformation and the position of the tree trunk indicate deformations of the
pavement, rather than of the building itself. Horizontal and vertical displacements of about 7
cm were measured. No liquefaction ejecta were observed in the perimeter of the building.
CASE 3: PIRAEUS BANK, LIXOURI BRANCH (38°12'7.65''N, 20°26'19.70'E)
The 2-story structure (GPS Coordinated 38°12’7.65”N, 20°26’19.70”E) is supported by a
grid of 20 steel piles, 1 m in diameter and 15 m in length. The structure appears to have stayed
in place without any displacement at two of the corners. Measured settlements reached 2.4 cm
at the entrance of the building, and 4.2 cm settlement at one corner (Fig. 8.7.4). Although it
seems that the ground has settled, the structure remained in place. Observations of non-
structural components damage in several bank structures are presented in the Chapter 11.
Figure 8.7.4. Case 3: Lixouri Branch of Piraeus Bank (38°12’7.65”N, 20°26’19.70”E, 2/18/14).
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CASE 4: ST. NICHOLAS CHURCH BELL TOWER (38°12'9.43''N, 20°26'17.63''E)
The bell tower of St. Nicholas church (GPS coordinates 38°12’9.43”N, 20°26’17.63”E; see
Fig. 8.7.5) appears to have suffered differential settlement. Settlement at the west side and
uplift at the east side of the building resulted in the tower tilting toward the church (Figs.
8.7.6b,c).
It can also be seen that the bell tower has leaned against the church structure adjacent to it
(Fig. 8.7.6c, insert), damaging the church roof. Settlements of 2 cm were measured at the SE
and NE corner. No settlements were observed at the perimeter of the church.
Figure 8.7.5. Case 4: St. Nicholas Church Bell tower location (GPS coordinates 38°12'9.43"N,
20°26'17.63"E, 2/18/2014).
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Figure 8.7.6. Case 4: St. Nicholas Church Bell Tower differential settlement (38°12'9.43"N,
20°26'17.63"E, 2/18/14).
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CASE 5: POWER TRANSFORMER PILLAR (38°11'55.63"N, 20°26'20.56"E)
A power transformer pillar in Lixouri (38°11'55.63"N, 20°26'20.56"E) suffered differential
settlement. One of the support columns appeared to have punched in the ground for 1.7 cm,
while the other one remained in place. This behavior could be attributed to structural response
influenced by SSI, with verification by site specific studies.
Figure 8.7.7. Case 5: Power transformer pillar differential settlement (38°11'55.63"N, 20°26'20.56"E,
2/19/14).
CASE 6: CAFÉ “AEN PLO” (GPS COORDINATES: 38°12'3.52"N, 20°26'20.00"E)
Café “Aen Plo” is located in the first row of residential buildings in Lixouri (GPS
Coordinate: 38°12'3.52"N, 20°26'20.00"E), approximately 45 m from the quay walls (Fig.
8.7.8). It is founded on steel piles (Fig. 8.7.8.). It appears that the structure suffered minor
damage, although a detailed structural assessment has not been performed.
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Figure 8.7.8. Case 6: Café “Aen Plo” location and street view (38°12'3.52"N, 20°26'20" E, 2/19/14).
Figure 8.7.9. NE corner of Café “Aen Plo” NE corner ground failure (2/19/14).
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In the NE corner of the structure, 3.8 cm of vertical and 1.9 cm of horizontal displacements
were measured (Fig. 8.7.9). It appears that the structure remained in place, but the ground
moved towards the seafront as the result of liquefaction. The owner confirmed that no sand
boils were observed during or after the earthquakes near the structure and on the road in front
of it.
However, the settlements at Café “Aen Plo” could be attributed to liquefaction occurring
deep below the ground surface, which did not lead to bearing capacity failure or excessive
settlements due to the existence of a “protective cap” of unsaturated fill on top of the liquefied
ground at some depth. This layer of non-liquefiable material may exist due the topography of
the area, which has a mild inclination towards the sea, thus incurring a deepening of the ground
water level with distance from shore.
The difference in ground elevation from the shore is approximately 2 m at a distance of
100 m and 4 m at a distance of 170 m, where pavement cracks essentially diminish. If the
topographic difference is correlated to a similar deepening of the ground water table, this
condition would allow for sufficient thickness of the protective zone to prevent bearing
capacity failure and excessive settlement (Karamitros et al., 2013). This “deep” liquefaction
could also explain the relatively mild structural damage to the Lixouri buildings, since it could
essentially act as a natural base isolator for the buildings. Although this is a credible
explanation in the framework of a geotechnical reconnaissance effort, site-specific
geotechnical investigations and analyses using the recorded ground motions of both main
events and their aftershocks are required to substantiate this possibility.
CASE 7: 2-STORY R/C BUILDING (38°11'36.08"N, 20°26'19.90"E)
Another case of free-field soil settlement was observed at the location of a 2-story
Reinforced Concrete (R/C) building located near the shore south of Lixouri (GPS coordinates
38°11'36.08"N, 20°26'19.90"E).
Although it cannot be totally ruled out, the investigators did not identify settlement of the
building itself or evidence of liquefaction. The building itself had no apparent structural
damage and suffered non-structural damage such as collapse of its chimneys and roof tiles.
As shown on Fig. 8.7.10, the soil around the building settled uniformly by about 3 cm. As
a result, the (uncracked) mortar of the building was dislocated from the paved ground.
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Drainage pipes (were also dislocated from their collective pool as the result of surrounding
ground settlement. The observations could be attributed to cyclic softening and subsequent
settlement of the unsaturated fill set around the building.
Figure 8.7.10. Case 7. Ground settlement in the perimeter of 2-story R/C building south of Lixouri.
Location at the top part of this figure (GPS Coordinates 38°11'36.08"N, 20°26'19.90"E, 2/19/14).
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CASE 8: MONASTERY OF VIRGIN KECHRIONOS (38°13'26.19''N, 20°25'43.36''E)
The 200-year old Monastery of Kechrionos located 2.5 km north of Lixouri, 900m from
the sea shore, on the road between Aghios Dimitrios and Loukerata (38°13’26.19”N,
20°25’43.36”E) suffered significant structural damage. It is said that the Monastery was
established by three former prisoners kept in Algeria who, after praying to Virgin Mary for
release on the night of August 23 of 1694, they woke up next day on the site. The main building
was constructed in 1826 and suffered damaged during the earthquake of 1867 and almost
collapsed during the 1953 earthquake.
An interesting observation illustrated in Figures 8.7.11 – 8.7.14 is the structural and non-
structural failure that occurred primarily along the E-W direction (i.e., in-plane shear cracks of
the front garden gate, fall of non-structural elements and evident rotation of the main gate
lights). While the NS and EW components of the earthquake motions contained potential
directivity effects (see insert of Fig. 8.7.12 from the 2nd event), within the assumed structural
period of interest between 0.1 and 0.3 seconds, the spectral accelerations did not vary
significantly. This would make the Kechrionos Monastery an interesting future case study to
study potential site effects, directivity and, possibly, SSI.
Note that additional detailed structural observations on the churches of Cephalonia are
presented in the Chapter 11.
Figure 8.7.11. Case 8: Kechrionos Monastery. Shear failure on external gate (left) and rotation of
exterior lights (right), both along the EW direction (38°13'26.19"N, 20°25'43.36"E, 2/8/14).
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Figure 8.7.12. Orientation of structural and nonstructural damage relative to the EW direction.
(38°13'26.19"N, 20°25'43.36"E, 2/8/14). Insert: the 3 components of spectral accelerations in the 2nd
event.
Figure 8.7.13. Comparison of the external and main gate of the Kechrionos Monastery prior (left) and
after the 2014 earthquakes (right).
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Figure 8.7.14. Case 8: Kechrionos Monastery. Out-of-plane collapse of non-structural elements (left).
Close view of the main gate pillar dislocation together with diagonal cracks of the external masonry.
CASE 9: NATIONAL BANK, LIXOURI BRANCH (38°12'7.8"N, 20°26'19.8"E)
The Lixouri branch of the National Bank of Greece (Fig. 8.7.15), is located in the front row
of buildings parallel to the port shoreline (GPS Coordinates: 38°12'7.8"N, 20°26'19.8"E) and
is adjacent to Case 3 (Piraeus Bank branch). The building experienced significant structural
and non-structural damage that resulted in closing this branch. Details on these types of damage
is presented in the Chapter 11.
Figure 8.7.15. Case 9: National Bank of Greece, Lixouri Branch located in the front row of buildings
parallel to the shoreline (GPS Coordinates: 38°12'7.8''N, 20°26'19.8''E).
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Significant ground deformations were observed towards the inland EW direction due to
potential liquefaction or ground deformations of the uncontrolled fill below the pavements,
most evident at the SE corner of the bank (Fig. 8.7.16a). The reconnaissance teams observed
lateral and vertical deformations between the base of the structure and the sidewalk. The
maximum vertical settlements (or dislocation between the base of the structure and the
sidewalk) was about 4 cm (Fig. 8.7.16b), while the lateral deformations between the base and
sidewalk or sidewalk and road pavement were generally 1 cm or less. A summary of the vertical
deformations between the base of the building and its connection to the sidewalk along the
façade of the bank is shown on Fig. 8.7.17.
Figure 8.7.16. Case 9: Observations of deformations of the: (a) ground; (b) sidewalk connection to base
of building; and (c) cabinets of interior EW wall. (GPS: 38°12'7.8''N, 20°26'19.8''E, 2/9/14).
Figure 8.7.17 Case 9: Summary of vertical (exaggerated) deformations between base of building and
its connection to the sidewalk along the façade of the bank. (GPS: 38°12'7.8''N, 20°26'19.8''E, 2/9/14).
~ 4 cm
EW Wall
(b)
(c)
(a)
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CASE 10. SERIES OF STRUCTURES DESIGNED PER GREEK CODE (EAK2000)
Building damage is systematically presented in the Chapter 11 as a function of the seismic
code that it was designed for. In this section, we bring the attention to a series of newly
constructed structures that may be worth investigating with reference to their SSI effects,
shown on Figs. 8.7.18 and 8.7.19. They are 3-story Reinforced Concrete (R/C) buildings,
designed in accordance with the latest Greek Seismic Code (EAK2000).
Figure 8.7.18. Case 10. Locations of the 3-story structures designed with the latest seismic code
EAK2000. (GPS coordinates 38°13'48.19"N, 20°25'53.20"E, 2/9/14).
The design base shear of these buildings was approximately equal to Vsd = (ag × 2.5/q) ×
W = 0.36g × 2.5 × W / 3.5 ≈ 0.25 g W (where ag is the seismic coefficient and q is the force
reduction factor as per EAK2000). The recorded spectral acceleration at the fundamental
period of the structures (estimated around 0.25 sec) was about 0.7 g (for 5% damping), which
generated a base shear that exceeded the design value by almost 3 times.
It appears that the lateral load resisting systems of these structures responded elastically
during both the 1st and 2nd main events. Although in some cases extensive damage of the infill
masonry was observed, the load bearing system remained intact. The impressive lack of
damage may be attributed to different factors that either increase the available strength of the
buildings (such as inherent over-strength due to the use of minimum, code-prescribed
reinforcement and minimum dimensions, statistical over-strength of materials, and the
beneficial, seismic energy absorbing role of the masonry walls), and/or to factors that have
possibly reduced the imposed base acceleration due to site effects or SSI phenomena. The high
demand-to-nominal capacity ratio, small distance from the shore (less than 500 m) and the
presence of settlements in nearby structures makes these desirable case studies.
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Figure 8.7.19. Cases of buildings designed to EAK2000 experienced no damage to their load bearing
system due to multiple sources of over-strength. Possible beneficial effects of SSI could have played a
factor and should be studied further (38°13'48.19"N, 20°25'53.20"E, 2/9/14).
CHAPTER 9
Rigid Blocks
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9.1 Overview and Key Observations
INTRODUCTION
One of the defining characteristic of the 1st and 2nd main earthquake events was the very
extensive damage observed in nearly all 18 cemeteries of the Paliki peninsula and 9
additional cemeteries in the island, whose locations are shown in Fig. 9.1.1.
This damage, of unprecedented magnitude in the earthquake history of Greece, was in
stark contrast with the overall excellent performance of the building stock in the same most-
severely-shaken region. Thus, it attracted the attention of most reconnaissance teams,
including AUTH, DUTH, HUA, ITSAK, NTUA, UMI, UPatras, UTH, and practitioners
MRCE and Diatonos Mechaniki. This Chapter presents a synthesis of the findings of all
teams involved.
Figure 9.1.1 Locations of 27 cemeteries inspected during reconnaissance.
TYPES OF DAMAGE AND CONTROLLING PARAMETERS
Description of typical tomb blocks and ornamental features are described in the next
section of this chapter. The ground deformation German satellite TerraSAR interferometry
data from the 2nd event presented in Section 7.3 can provide insight in understanding the
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heavy damage in cemeteries, particularly on the thrust component of the predominantly
strike-slip fault rupture. A maximum ground deformation of 12 cm occurred near the middle
NS axis of the Paliki peninsula, while on the eastern coast (where Lixouri is located), the
movements reached 7 cm in the opposite direction as shown on Fig. 7.3.2. Keeping this
information in mind, we have classified repeated patterns of damage in five major
categories listed below, along with representative figures.
1. Toppling of slender marble plates that had been serving as monuments (headstones) –
Figs. 9.1.2 and 9.1.3;
2. Sliding and rotation of heavy marble blocks on their pedestals – Figs. 9.1.4 to 9.1.8;
3. Sliding and rotation of multi-block monuments on several interfaces along their height
and in different directions – Figs. 9.1.9 and 9.1.10;
4. Combination of 1 and 3 with multi-block monuments: sliding and rotation on one
interface and toppling of the top block – Figs. 9.1.11 and 9.1.12;
5. Breaking of covering tomb slabs, usually along a line perpendicular to their long side
and rather rarely (and unexpectedly) along a line parallel to the long side – Figs. 9.1.13
and 14.
The parameters influencing the behavior of such rigid blocks relate to the geometry of
the block and the nature of their seismic excitation. A partial list of the parameters includes:
Block slenderness, indicated by the ratio, h/b
Block weight, W
Frictional capacity of interfaces, measured through the coefficient of friction, μ, but
also dependent on the presence (or not) of gluing or grout material
Peak Ground Acceleration , A or PGA, and velocity-step ΔV
Dominant earthquake frequency,
Detailed sequence of pulses of the seismic excitation
Intensity of 2nd (horizontal) and 3rd (vertical) components of the ground
acceleration, and even the time-dependent phasing between the various
components.
Evidently, the problem of rocking and toppling on a rigid base indeed is chaotic, to the
point that back analyses to estimate the ground shaking that has produced a certain
displacement or rotation is a futile exercise. Almost as chaotic is the problem of sliding.
Main factors which affect the shaking-related parameters above are the source
mechanism and the rupture propagation effects (i.e., forward or backward directivity), and
certainly the prevailing soil conditions, since the cemeteries are invariably constructed on
soil and not in rock. The variation of the extent of damage from place to place is indicative
of differences in these seismological and geotechnical conditions which affect the ground
shaking.
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SPATIAL DISTRIBUTION OF DAMAGE
The extent of the damage in investigated cemeteries is a clear evidence of the
tremendous intensity of the motion — in fact of all three components of motion. This is
compatible with strong motions that were recorded in Lixouri and Chavriata (PGAs on the
order of 0.6 g to 0.7 g, peak velocities as high as 120 cm/s in Lixouri).
Interestingly, many cemeteries were built on higher ground, often on a hill, as the
characteristic example would be the Chavriata cemetery. It is reasonable therefore to expect
that topographic amplification has possibly contributed to the intensity of ground motions.
In Section 9.3, the extent of damage in all cemeteries is correlated tentatively with the
distance from the fault. The significant scatter, especially substantial differences in the level
of damage observed among adjacent cemeteries, indicates the important contribution of all
above mentioned factors on the observed performances listed above (related to both
geometry-material of the blocks and their seismic excitation).
Figure 9.1.2. Overturning of the headstone in Lixouri cemetery taken on 2/9/14 by NTUA
team (GPS coordinates: 38.192586, 20.438769).
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Figure 9.1.3. Toppling of marble head-cross in Lixouri cemetery taken on 2/9/14 by
NTUA team (GPS coordinates: 38.255833, 20.421111).
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Figure 9.1.4. Displacement and rotation of a marble vase, responding as a rigid body at Livadi
cemetery taken on 2/8/14 by NTUA team (GPS coordinates: 38.255555, 20.421111).
(a)
(c)
(a) (b)
(c) (d)
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Figure 9.1.5. (a) A case of “double-rotation” in the Livadi cemetery: first rotates the massive
headstone structure and then the marble vase. (b) Sketch of the dimensions and displacements of
the slender marble artifact (GPS coordinates: 38.255833, 20.421111; NTUA team, 2/8/14).
12 cm
21.5 cm
15 cm
8.2 cm
12 cm
12 cm
3 cm
8.5 cm
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Figure 9.1.6. Rotation of a massive headstone in Chavriata (GPS coordinates: 38.183219,
20.389813). Photo taken by NTUA on 2/10/14.
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Figure 9.1.7. Detailed views of the previous photo taken on 2/10/14 by NTUA team (GPS
coordinates: 38.183219, 20.389813).
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Figure 9.1.8. Sketch of the dimensions and displacement of rotated headstone.
112 cm
68 cm
182 cm
22
30 cm
87 cm
51 cm
64 cm
24 cm
64 cm
PLAN VIEW
ϕ ϕ = tan-1(24/64) ⇒
⇒ ϕ = 20o
46 cm
7
PLAN VIEW
14 cm
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Figure 9.1.9. Double rotation of the headstone and its base in opposite directions. The photo on
the left is a plan view of the rotation at the base. Lixouri cemetery, dated 2/9/14 (GPS coordinates:
38.192561, 20.438797).
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Figure 9.1.10. Detailed views of the rotational movement located at three different interfaces
(shown with red rectangles and arrows). Rotations occurred in opposite directions. Lixouri photo
taken on 2/9/14 by NTUA team (GPS coordinates: 38.192780, 20.438486).
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Figure 9.1.11. Detailed views of the rotated lower marble pedestal and toppling of the slender cross
headstone. Lixouri cemetery, photo taken on 2/9/14 by NTUA team (GPS coordinates: 38.192436,
20.438666).
(a)
(b) (b) (c)
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Figure 9.1.12. Toppled headstone (top) and horizontal slippage of tomb panel (bottom). Chavriata
cemetery photo taken on 2/11/14 by NTUA team (GPS coordinates: 38.183013, 20.389619).
Figure 9.1.13. Rotation of several grave ledgers at the same direction in Livadi (GPS coordinates:
38.255833, 20.421111). Photo taken on 2/8/14 by NTUA team.
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Figure 9.1.14. Cracked marble panels, toppled artifacts and overturning headstones in Kourouklata
(GPS coordinates: 38.242500, 20.474166]. Photo taken on 2/8/14 by NTUA team.
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9.2 Detailed Reconnaissance
OBSERVATIONS IN CEMETERIES
Traditional Greek cemeteries feature above-ground tombs aligned in the east-west
direction, all bearing crosses and most bearing photograph frames, flower vases and similar
grave markings. This section summarizes the findings of detailed reconnaissance surveys
on the rigid block response in cemeteries of Cephalonia (Fig. 9.2.1).
The information presented in this section was gathered through five field investigations
during the period of January 27 to February 23, 2014. In total, 27 cemeteries were inspected:
18 of which are located in the Paliki peninsula and 9 on the main island. The 18 cemeteries
of the Paliki peninsula inspected cover almost all cemeteries in the meioseismal area. The
scope of reconnaissance studies was to document and identify possible damage patterns
that might be caused by a combination of variety of factors including proximity to source,
near-fault earthquake directivity, and local site effects. Note that this section does not
address any hanging or foot wall effects, since the actual trace of the fault (or faults) is yet
to be determined. The following Section 9.3 "Statistics of observed failures" summarizes
key statistical observations for all cemeteries discussed in this section.
Figure 9.2.1. Reconnaissance of 27 cemeteries in Cephalonia. Colored dots indicate percentage of
toppled tomb objects: red for more than 65%, yellow 30-65%, and green less than 30%.
The Vouni village cemetery is the only one where observations were made after both
the 1st and 2nd events. After the 1st event, the Vouni village cemetery experienced severe
damage (Fig. 9.2.2a). Following the 2nd event, objects that were still standing after the first
event, eventually toppled, as shown on Fig. 9.2.2b.
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Figure 9.2.2. Vouni village cemetery [GPS: 38.178456, 20.404778] toppled objects following the:
(a) 1st event (on 1/28/14) and (b) 2nd event (taken on 2/20/14). Photos by ITSAK and DUTH teams.
The rest of cemeteries were assessed by the GEER reconnaissance teams only after the
2nd event. Therefore, safe conclusions cannot be drawn about the time of the observed
damage in the majority of the cemeteries inspected. Local witnesses indicated that severe
cemetery damage observed in the Paliki peninsula was induced by the 1st event and
increased by following the 2nd event.
However, the investigators could not verify these statements in most of the cemeteries
based on our observations solely without analytical studies. In fact, Fig. 9.2.2 contradicts
this assertion, since minimal damage was caused by the 1st event, while most of the damage
seems to have been inflicted by the 2nd event.
Figure 9.2.3. Objects toppled mainly towards the East: (a) Atheras [38.311280, 20.418498] and (b)
Kontogennada East [GPS: 38.250936, 20.396137]. Photos by AUTH team on 2/11/14.
(a) (b)
(a) (b)
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Figure 9. 2.4. Cases of tomb objects toppling to the West: (a) Vouni [GPS: 38.178455, 20.404778]
and (b) Atheras [GPS: 38.311280,2 0.418498]. Photo by DUTH and AUTH teams on 2/11/14.
Notably, in most cemeteries inspected, the rigid objects (crosses, vases, markings)
placed on the tombs generally oriented in the EW direction, persistently toppled towards
the East (Fig. 9.2.3). In very few cases, crosses toppled towards the West (Fig. 9.2.4). This
observation may suggest strong near-field effects, with a single or multiple pulses being
responsible for the almost uniform direction of toppling. Analyses based on recorded
ground motions is needed to confirm near-field effect assumption. However, analytical
investigations in the literature reveal sensitivity of the direction of toppling to details of the
rocking block geometry, restitution coefficient, and excitation waveform (assuming
horizontal rocking plane), which make the possibility of unilateral topping hard to justify.
No systematic effort has been conducted to establish if the rocking plane was indeed
horizontal, or soil settlements caused an inclination in the direction of the grave (i.e., in
East). Likewise, no variability of damage related to the grave construction method was
established, since by inspection no major construction variations were identified among the
total of ten funeral homes of the island by inspection.
The principal cause of tomb damage was object toppling on the grave marble slab,
resulting in rupturing the latter. Other types of damage observed in tombs were slippage,
vertical separation, and/or rotation of blocks and tombstones, without toppling. Marble
blocks are displaced and rotated as seen in Fig. 9.2.5 at the cemetery of Chavriata [GPS:
38.183026, 20.389692]. Similar response was observed at the southern cemetery of
Kourouklata, behind the church shown in Fig. 9.2.6 [GPS: 38.242544, 20.474056].
(a) (b)
GEER/EERI/ATC Cephalonia, Greece 2014 9-Rigid Blocks Report Version 1 9-18
Figure 9.2.5. Rotation of a massive headstone, responding as a rigid body without toppling,
at the Chavriata cemetery [GPS: 38.183219, 20.389813]. Photo by NTUA team on 2/10/14.
Another interesting case of marble block dislocation was observed in the Livadi
cemetery [GPS: 38.255689, 20.421035]. Notice the practically identical type of sliding and
rotation of two neighboring low rise marble block constructions (A and B) on Fig. 9.2.7(a).
The detail in Fig. 9.2.7(b) is related to marble block construction B, which reads a
displacement of 8.7 cm to the North, 8.1 cm to the East, and a counter-clockwise rotation
of approximately 3.5o. If these displacements were due to a single shaking, they could
qualitatively indicate that ground motions at the Livadi cemetery had comparable intensities
in both the NS and EW directions. Since reconnaissance was performed by the UTH team
only after the 2nd event, this hypothesis cannot be confirmed. The observed damage could
likely involve asymmetric friction under the blocks or even a torsional excitation
component, and possible variations in cohesive/frictional resistance under the blocks,
especially block A.
It is unclear whether the distance from source (fault trace and dip angle not precisely
determined by seismologists yet) in the meioseismal area was as important as soil and
topographic conditions. In the village of Skineas [GPS: 38.240479, 20.395151], 7% of tomb
objects toppled, while the rest are still standing (Fig. 9.2.8a). In contrast, just 1 km away,
at the village of Vlihata [GPS: 38.238268, 20.403932], more than 70% of objects
GEER/EERI/ATC Cephalonia, Greece 2014 9-Rigid Blocks Report Version 1 9-19
overturned (Fig. 9.2.8b). In general, object toppling was concentrated in the Paliki
peninsula at a rate of about 2/3 (i.e., on average 67% of the objects toppled – see cemeteries
observations 1 to 18 of Table 9.3.1, sorted from North to South). On the main island,
observed toppling had an approximate rate of 1/5 (average of large dataset with variable
distances from the source) and essentially zero at the east side of the island.
Figure 9.2.6. Headstone rotation without toppling at the south cemetery of Kourouklata [GPS:
38.242361, 20.474188]. Photos by NTUA team on 2/8/14.
Figure 9.2.7. Livadi cemetery [GPS: 38.255689, 20.421035] after the 2nd event: (a) Displacement
and rotation of two neighboring low rise marble block constructions (A and B) and (b) Detail of
displacement and rotation of marble block construction B. Photos taken by UTH team on 2/8/14.
(a) (b)
A B B
North
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Figure 9.2.8. In (a) Skineas [GPS: 38.240479, 20.395151] a mere 7% of objects toppled; in 0.8 km
east at (b) Vlichata [GPS: 38.238268, 20.403932] 71% of objects toppled. AUTH photos, 2/11/14.
Nevertheless, the extent of damage of the cemeteries investigated is a clear evidence of
the tremendous intensity of the ground motion, probably in all three components. This is
compatible with the strong motions that were recorded in Lixouri and Chavriata (PGAs of
the order of 0.6 to 0.7g, peak velocities reaching 120 cm/s in Lixouri). Since many
cemeteries were often built on hills, it is reasonable to expect that topographic amplification
has contributed to the intensity of ground motion in many cases. Strong evidence supporting
this assumption was found at Chavriata cemetery, where 87% of tombs toppled (Fig. 9.2.9).
Figure 9.2.9. View of total destruction view at Chavriata cemetery [GPS: 38.183013, 20.389619]:
broken marble panels, toppled artifacts, overturned headstones. Photos by NTUA team on 2/10/14.
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Cemeteries on the east side of Paliki peninsula were most severely damaged (Lepeda,
[GPS: 38.17962, 20.434612], Lixouri, [GPS: 38.192880, 20.438620], Aghios Dimitrios,
[GPS: 38.223752, 20.428779], Soullari, [GPS: 38.185414, 20.415757], and Chavriata,
[GPS: 38.183026, 20.389692]). The toppling rates in these cemeteries were over 80%,
which may be related to their proximity to the 2nd event fault (if its trace is indeed located
offshore the eastern part or near the centerline of the peninsula.)
Figure 9.2.10. Two Kourouklata cemeteries [GPS: 38.243401, 20.474875] where: (a) 59% (north)
and (b) 76% (south) of objects toppled. Photos by UPATRAS team on (a) 2/11/14 and (b) 2/8/14.
At the main part of Paliki (e.g., at the village of Kourouklata [GPS: 38.243401,
20.474875], objects toppled at a rate of 76% and 59% at the two cemeteries (Fig. 9.2.10).
Cemeteries on the east side of the island were not significantly affected. Overall, it is clear
from our reconnaissance that adjacent cemeteries could exhibit markedly different
responses. Figure 9.2.11 presents an overview the cemetery object toppling rates in Paliki
peninsula.
(a) (b)
GEER/EERI/ATC Cephalonia, Greece 2014 9-Rigid Blocks Report Version 1 9-22
Figure 9.2.11. Cemetery reconnaissance at North Paliki peninsula. Red dots indicate object toppling
rate greater than 65%, yellow from 30-65% and green with less than 30%. Observations indicated that adjacent cemeteries could exhibit markedly different response.
OTHER RIGID OBJECTS
This section presents representative observations of the seismic performance of rigid
blocks or monuments besides cemeteries. Data provided in this section refer mainly to
marble monuments and statues that suffered a rigid body motion (i.e., displacement and/or
rotation), or even toppled after the 2nd event.
Two marble statues standing opposite to each other at the entrance of Lixouri City Hall
were of particular interest (Fig. 9.2.12, 38°12'3.53"N, 20°26'14.92"E). Following the 1st
event, the statue located north of the building entrance (Fig. 9.2.12b) displaced and slightly
rotated towards the North without collapsing, since it was supported by the wall behind it.
The trace of the original location of its base is visible, indicating an almost uniaxial
displacement of approximately 40 cm. The top portion of the statue eventually toppled after
the 2nd event towards the SE direction (Fig. 9.2.12c). A similar response was recorded (Fig.
9.2.12a) for the opposite standing statue (south of entrance), which also overturned in the
same (SE) direction.
Another case of rotation of a marble statue was recorded close to Argostoli Customs
building (Fig. 9.2.13, 38°10'47.94"N, 20°29'22.47"E), where a slight rotation towards the
North was recorded. A similar response of a marble monument of Ilias Antipas is shown in
Fig. 9.2.14 (38.18305°N, 20.50030°E), where a drum of the monument rotated without
evidence of lateral displacement. Rigid-body lateral displacement followed by a slight
rotation at different levels of a monument was observed near Lixouri (Fig. 9.2.15,
GEER/EERI/ATC Cephalonia, Greece 2014 9-Rigid Blocks Report Version 1 9-23
38°13’32.85’’N, 20°25’46.42’’E). Overturning and collapse of two marble drums was
documented at Lixouri, including toppling off a war monument (Fig. 9.2.16, 38o11'51.7''N,
20o26'17.3''E) towards the S-SW direction. Two additional toppling cases of a massive
Corinthian-type capital carrying a heavy top slab and a statue are shown in Figs. 9.2.17 and
9.2.18, respectively.
Figure 9.2.12. Two marble statues standing opposite to each other at the entrance of Lixouri City
Hall (38°12'3.53"N, 20°26'14.92"E). (a) Overturned statue south of entrance recorded by UTH after
2nd event; (b) Displaced but still standing statue north of entrance after 1st event (ITSAK photo,
1/28/14); (c) Top of statue toppled after the 2nd event (Photo by ITSAK – AUTH-LSDGEE teams
on 2/11/14).
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Figure 9.2.13. Marble statue close to Argostoli Customs building (38°10'47.94"N, 20°29'22.47"E):
Slight base rotation. Photo by ITSAK – AUTH-LSDGEE teams on 2/11/14.
Figure 9.2.14. Monument of Ilias Antipas mainly rotated (38.18305° N, 20.50030°E). The
rectangular sketch shows rotated part at its base (in cm). Photo by UPATRAS teams on 2/8/14.
(units in cm)
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Figure 9.2.15. Marble monument near Lixouri (38°13'32.85''N, 20°25'46.42''E): Lateral
displacement without significant rotation (dimensions in cm). Photo by UPATRAS team on 2/8/14.
Figure 9.2.16. Marble monument at Lixouri (38°11'51.7''N, 20°26'17.3''E). Dislocation and
toppling of upper two marble blocks towards S-SW direction. Photo by LSDGEE-AUTH team on
2/11/14.
(units in cm)
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Figure 9.2.17. Overturning of massive Corinthian-type capital carrying a heavy top slab in Lixouri
(GPS coordinates: 38.192713, 20.43]. Photo taken by NTUA team on 2/9/14.
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Figure 9.2.18. The house across the street of the Public Library of Lixouri. No damage is noticed, but
a statue overturned (marked with turquoise circle). Photo by NTUA team on 2/10/14.
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Toppling and slight rotation of a rigid masonry hollow block was observed in a shoreline road
house in Lixouri, adjacent to the local branch of the National Bank of Greece located (Fig.
9.2.19). These blocks, called “little churches of the souls,” are often seen in Greece in memory
of deceased (usually at locations of car accidents).
Figure 9.2.19. Toppling and rotation of rigid block at a shoreline road house next to Lixouri National
Bank [38o12'9''N, 20o26'19.8''E]. Measurements by Diatonos Mechaniki; MRCE photos, 2/10/14.
5.18 m
48 cm
70 cm
A
B
A'
B'
(AA') = 37 cm (BA') = 60 cm (AB') = 56.5 cm (BB') = 28 cm
Sho
relin
e d
irec
tio
n
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9.3 Statistics of Observed Failures in Cemeteries
Table 9.3.1 summarizes statistics of toppling of objects resting on tombs from all
cemeteries visited by the GEER reconnaissance teams, mainly after the 2nd event. For each
cemetery, the following data are tabulated: (a) the percentage of toppled objects over total
number of tombs (not accounting for other effects, such as sliding/rocking/uplift without
toppling); (b) a rough estimate of the general geologic conditions of each cemetery; and (c) a
rough estimate of the altitude. Cemeteries are highlighted according to toppling rate, in three
categories, rated with respect to toppling percentage from minor (0-30%), to medium (30-65%)
and to extensive (65-100%). These statistics are preliminary as the number of observations and
toppling rates are being revised as more data become available and incorporated at this time.
Fig. 9.3.1 shows the toppling rate correlated with the (approximate) shortest distance from
the hypothetical extension of the fault trace of the 2nd event, which runs almost in the NS
direction, from immediately West of Atheras village [GPS: 38.311280,20.418498] to
immediately East of the Soullari village [GPS: 38.185414,20.415757]. Our preliminary
assumption is supported by the interferometry map of Section 7.3 and the tectonic setting of
the area (insert of Fig. 9.3.1).
Nevertheless, the exact fault trace, and therefore the exact distance, is still unknown, and
certainly we do not know the seismogenic fault of the 1st event, which also contributed at least
to displacements and rotations of the monuments. Mechanisms of these events have not been
fully understood either other than that they were both predominantly strike-slip with a thrust
component, especially in the 2nd event. While interpreting statistics given in Fig. 9.3.1, one
should be kept in mind that this is preliminary, indicating:
1. Four cemeteries (Aghios Dimitrios north & south, Lixouri and Lepeda) at the eastern coast
of the Paliki peninsula exhibited the largest toppling rates, with average greater than 95%.
2. There was surprising low toppling rate at in the vicinity of the fault, at Kontogennada (west)
and Skineas, 18% and 7% respectively.
3. Adjacent cemeteries presented significantly different toppling rates. In the two (western
and eastern) cemeteries of Kontogennada, 18% and 69% toppling rate was witnessed,
respectively. In Skineas the rate was 7% and in Vlichata, less than 1 km away, the rate was
71%. In both cases, the general geologic setting and altitude were roughly the same.
4. The correlation shows significant scatter, which is an indication of the many parameters
that influence the performance of the rigid blocks.
GEER/EERI/ATC Cephalonia, Greece 2014 9-Rigid Blocks Report Version 1 9-30
Figure 9.3.1. Correlation of damage in all cemeteries inspected to the shortest distance from the
(hypothetical) trace on the surface of the seismogenic fault of the 2nd event. Insert: geologic ΙΓΜΕ map
showing in blue the preliminary reference line used to calculate the distance to the cemeteries.
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Table 9.3.1. Summary of statistics from cemeteries: Entries 1 through 17 are in Paliki peninsula (west part of Cephalonia), ordered from North to South. Entries 18 to 26 are on the main (east) part of the island. Light red indicates toppling rate over 65%; light yellow from 30-65%; and light green less than 30%. Generalized geologic setting: A = Conglomerate, sandstone and limestone and B = Conglomerate and brecciated limestone with marls.
Entry % Generalized Altitude GeographicNo. Toppled Geology (m) Coordinates
1 Atheras 73 50 68 limestone / marls 255 38.311280,20.418498
2 Livadi 42 29 69 limestone / marls 42 38.255689, 20.421035
3 Kontogennada (west) 45 8 18 limestone / marls 243 38.251145,20.394948
4 Kontogennada (east) 16 11 69 limestone / marls 253 38.250936,20.396137
5 Aghia Thekla 29 21 72 limestone / marls 255 38.245347,20.384113
6 Kalata / Aghios Dimitrios 46 22 48 limestone / marls 210 38.242973,20.387675
7 Skineas 67 5 7 limestone / marls 205 38.240479,20.395151
8 Vlichata 34 24 71 limestone / marls 175 38.238268,20.403932
9 Aghios Dimitrios (north) - - 95 sandstone / limestone 124 38.234006,20.424175
10 Aghios Dimitrios / I. Moni Kechriona 9 8 98 sandstone / limestone 44 38.224166, 20.428573
11 Havdata 200 50 25 limestone / marls 145 38.202990,20.387002
12 Lixouri - - 95 sandstone / limestone 6 38.192880,20.438620
13 Soullari 40 32 80 sandstone / limestone 50 38.185414,20.415757
14 Chavriata 110 96 87 sandstone / limestone 60 38.183026,20.389692
15 Vouni 50 34 68 sandstone / limestone 60 38.178455,20.404778
16 Mantzavinata (west) / Aghia Sofia 53 37 70 sandstone / limestone 62 38.177311,20.408334
17 Mantzavinata (east) 48 33 69 sandstone / limestone 53 38.176944,20.410314
18 Lepeda - - 85 sandstone / limestone 80 38.17962, 20.434612
19 Zola - - 10 limestone / marls 200 38.304909,20.465718
20 Makriotika / Aghios Gerasimos 20 0 0 limestone / marls 140 38.312289,20.559716
21 Agkonas - - 10 limestone / marls 280 38.299521,20.489215
22 Kardakata - - 10 limestone / marls 285 38.282360,20.473579
23 Kourouklata north 21 16 76 limestone / marls 255 38.243401,20.474875
24 Kourouklata south 61 36 59 limestone / marls 264 38.242544,20.474056
25 Grizata 56 0 0 limestone / marls 155 38.213876,20.650455
26 Drapano - - 30 limestone / marls 11 38.182783,20.499707
27 Aghios Nikolaos 100+ 0 0 limestone / marls 312 38.166312,20.714258
Village / Cemetery NameToppled Tombs
Total Tombs
CHAPTER 10
Infrastructure Networks
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
GEER/EERI/ATC Cephalonia, Greece 2014 10‐Infrastructure Networks Report Version 1 10‐1
10.1 Potable and Wastewater Networks INTRODUCTION
This section is based on the contribution by the Organization EYDAP (ΕΥΔΑΠ in Greek),
which is the Athens Water Supply and Sewerage Company (EYDAP SA). EYDAP responded
rapidly and sent field investigation and repair teams to assist with the assessment and retrofit
of the potable and wastewater networks of Cephalonia. A preliminary report on the action plan
and retrofit work entitled “Emergency Support provided to the Municipality of Cephalonia for
the repair of the damages which occurred after the January-February 2014 earthquakes” was
prepared (in Greek) by the General Department of Networks & Facilities and the Departments
of Potable Water Network Department and Waste Water Network / Quality Assurance
Department and became available to our team for incorporation in the GEER/EERI/ATC
report. This section was compiled by Mr. Dimitri Iliadelis of MRCE and Editors Zekkos and
Nikolaou, based on excerpts from the preliminary EYDAP report and feedback from the
reconnaissance teams that interacted with EYDAP personnel while in the island. The Editors
are grateful to EYDAP for providing this report and information and especially thankful to Mr.
George Sachinis of EYDAP who acted as our liaison with the organization.
EYDAP ORGANIZATION (ΕΥΔΑΠ)
EYDAP is the Athens Water Supply and Sewerage Company (EYDAP SA), founded in
1980 after a merger of the incumbent water supplier in Athens and Piraeus "Hellenic Water
Company S.A." (EEY SA) with the "Greater Athens Sewerage Organization" (OAP S.A.). It
is the largest organization of its kind in Greece. The Company serves approximately 4.3 million
customers through an extensive network of 2 million water meters and 9,500 km of water pipes.
The sewage sector serves 3.5 million residents with sewers spreading at almost 6,000 km. The
company’s objectives are to:
Provide water supply and sewage services.
Design, construct, install, operate, manage, maintain, expand and upgrade water supply and sewerage systems.
Pump, desalinate, process, transfer, store and distribute all kinds of water as a means of serving EYDAP’s object.
Implement projects and processes for collecting, transferring, storing, processing, and manage and dispose the wastewater treatment products.
GEER/EERI/ATC Cephalonia, Greece 2014 10‐Infrastructure Networks Report Version 1 10‐2
ACTION PLAN
EYDAP responded rapidly and sent field investigation and repair teams to assist with the
assessment and retrofit of the potable and wastewater networks of the island. The EYDAP
teams were supervised by the General Manager of Networks, Mr. Stefanos Georgiadis, the
Deputy General Manager of Networks, Mr. Konstantinos Vougouklakis, and the CEO Mr.
Antonis Vartholomaios.
Two teams were put together for the rapid immediate assessment and repair purposes in
the central EYDAP facilities in the capital of Athens and immediately departed in order to
arrive at the island as soon as possible (Fig. 10.1.1). These two teams were (i) potable water
team, consisting of four mobile immediate response units and one mobile coordination unit and
(ii) wastewater team with two mobile independent immediate response units.
Figure 10.1.1. EYDAP vehicles arriving from the central facilities in Athens to Cephalonia via ferry boat, with the investigation and repair teams members who were joined by local colleagues.
The mission team members included experienced engineers and technicians, carrying
technologically most up to date equipment and vehicles to allow them to work efficiently and
independently immediately following an emergency event. The engineers of the team are
specialized and trained in emergency response assessments, crisis management, and
collaboration with local agencies and communities. Concurrently with the rapid assessment
and as-needed repairs, the EYDAP teams performed monitoring and chemical analyses of
samples and collected network data to produce detailed GIS mapping of the potable and
GEER/EERI/ATC Cephalonia, Greece 2014 10‐Infrastructure Networks Report Version 1 10‐3
wastewater networks. The investigation and repair teams worked uninterruptedly on 24-hour
shifts until the networks were assessed and fully operable and all residents had access to potable
water. Details of the potable and wastewater network EYDAP missions are provided in the
following sections and can be seen in the video www.youtube.com/watch?v=Dyt7sZsrNYs .
POTABLE WATER NETWORK
Event No. 1 Investigation
The 1st earthquake event of January 26th 2014 did not produce alerting reports of major
damage in the water supply network. However, EYDAP engineers and technicians trained in
post-emergencies immediately travelled to the island to identify and restore any problems that
could had occurred. The focus areas were the towns of Argostoli and Lixouri, where small
scale restorations and minor repairs took place, since no major problems were identified. At
the end of this investigation full functionality of the network was restored.
Event No. 2 Investigation
The 2nd earthquake event, on February 3rd 2014, caused significant problems in the water
supply network. Immediately following this earthquake, an additional EYDAP investigation
was engaged to support the restoration of the network. Large scale repairs and replacements
took place until full functionality was achieved. The focus of the investigation was the town of
Lixouri, were the majority of the damage was concentrated, especially in the aged portions of
the networks. The actions taken in restoring the Lixouri networks after the 2nd event are
presented below. EYDAP’s personnel laconically summarized to the GEER/EERI/ATC
investigators their mission goal in one sentence: “We will not leave the island until each home
is supplied with clean water.”
Preparation. The preparation was well planned and thought out by the following actions:
i. Formation of investigation and repair team
ii. Selection of vehicles and equipment support
iii. Collection of support information, including maps (Fig. 10.1.2), digital elevation
models of the ground surface from satellite data (Fig. 10.1.3), and longitudinal
sections of the water reservoir.
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Figure 10.1.2. Digital Elevation Model (EYDAP, 2014).
Figure 10.1.3. Topographic map showing Lixouri water networks (EYDAP, 2014).
Deployment. Both investigation and repair teams departed immediately after the 2nd event
at 1 am on Feb. 6th, to board the first available ferry boat to Cephalonia.
Rapid Assessment. The investigation and repair teams, in coordination with the local
agencies performed a rapid assessment. Just 3 hours upon arrival to the island, the EYDAP
teams were planning for the investigation and restoration activities. Fig. 10.1.4 shows a GIS
map of the water network. The mapping involved a total of 36,191 m of pipes.
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As shown in Table 10.1.1, the material of these pipes consist of PVC by 42.3%, Asbestos
Cement by 30.5%, Polyethylene by 25.8%, and steel by 1.4%. A map of the network is shown
in Fig. 10.1.4. The assessment of the first day is shown on the map of Fig. 10.1.5, color
coordinated as follows: Green – normal operation; Yellow – significant fluctuations in
pressures; Orange – very low pressure; and Red – zero pressure.
Table 10.1.1. Potable water pipe network material and length in the town of Lixouri.
Figure 10.1.4. GIS mapping of a total of 36,191 m of potable water network pipes (EYDAP, 2014).
Figure 10.1.5. Rapid network assessment at the end of the first day (EYDAP, 2014)
Plastic Pipe Network (PVC) 15,295 42.3
Asbestos Cement Pipe Network (A/C) 11,041 30.5
Polyethylene Pipe Network (PE) 9,355 25.8
Steel Pipe Network (ST) 500 1.4
Material Length (m) % of Network
WATER PIPES
PE (Polyethylene) PVC (Plastic) A/C (Asbestos/Cement) ST (Steel)
PARALIA – LEPEDA PARALIA (BEACH)
LEGATATA
WEST LEGATATA
(NW SECTOR) NW SECTOR
AGORA
PRESSURE LEVEL
Zero Very low Major fluctuations Normal
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Mapping activities: Electronic mapping of the water networks was not readily available by
the local agencies. EYDAP formed a special task group responsible for digital mapping as this
was considered necessary to assess the condition and performance of the networks.
Repair activities
Day 1: A second subgroup was responsible for detecting and repairing the visible damages
and leaks. Photos of the repair activities during Day 1, a 24-hr shift, are shown in Fig.
10.1.6. Due to large number of leaks, most of the system could not maintain its pressure,
so nineteen additional valves were installed for the control of the water supply in the
various areas (Fig. 10.1.7). As shown in Fig. 10.1.8, at the end of the first day normal water
supply was secured inland.
Day 2: The EYDAP teams gradually connected areas to the network and performed leakage
tests. Once the system achieved positive pressures, “invisible” leaks were detected using
acoustic methods as well as hydraulic numerical simulations that were employed to identify
unexpected drops of the piezometric line and help in the detection of leaks (Fig. 10.1.9).
Days 3 to 12: During Days 3 to 12, the EYDAP teams inspected the water reservoir (tanks,
pipes), repaired damages and performed continuous adjustments in order to ensure stable
service. A bypass of the network pipes and alternative supply took place in areas where the
repair would have been too difficult or where the upgrade in supply was significant. For
the protection of the asbestos cement pipe network, a pipe rupture valve was installed since
the repair of the leaks would result in increase of pressures in the already distressed
network, which would likely cause new leaks. At the same time, in situ chemical analyses
were performed (regular and residual chlorine) to ensure the water quality and also to check
for leaks (which would decrease the quantity of the residual chlorine). The network
pressures upon completion of these activities were normal, as shown in Fig. 10.1.11. Since
Saturday February 8th 2014, 100% of the network in Lixouri and the surrounding areas was
fully restored.
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Figure 10.1.6. Examples of the numerous repair of leaks repaired (EYDAP, 2014).
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Figure 10.1.7. Nineteen new valves were installed by EYDAP shown with red dots.
Figure 10.1.8. Progress made at the end of the first day (EYDAP, 2014).
During the field operations, the investigation and repair teams gathered information to
generate a more detailed estimate of the hydraulic and mechanical network operations, in order
to submit proposals for the improvement and support of the network. EYDAP’s efforts have
then focused in the management of the pressures and the application of modern technologies
and special methodologies in network restoration. The organization considered that the main
goal of maintaining a steady pressure in the network that is necessary to ensure the quality of
the potable water was accomplished.
NORMAL OPERATION PARTIAL REPAIR
NW SECTOR
PARALIA - LEPEDA PARALIA AGORA
LEGATATA
WEST LEGATATA (NW SECTOR)
Valve
EYDAP Valve
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Figure 10.1.9. EYDAP Personnel repairing leaks during Day 2 (EYDAP, 2014).
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Figure 10.1.10. EYDAP Personnel repairing leaks Days 3 to 12.
Figure 10.1.11. Potable water network fully functioning at the end of repair activities.
NORMAL OPERATION
NW SECTOR
PARALIA - LEPEDA PARALIA AGORA
LEGATATA
WEST LEGATATA (NW SECTOR)
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Challenges Associated with Repair Activities
The challenges faced by the EYDAP teams can be summarized into three categories:
weather conditions, groundwater and social factors:
i. Weather Conditions: Rainfall not only made the efforts more difficult, but also affected
the groundwater table elevation.
ii. Groundwater: The groundwater elevation, the presence of wells, and the storm water
posed difficulties in assessing if potable water was spilling into the wastewater network.
To overcome this difficulty numerous additional chemical analyses had to be performed
to define the source of water entering the wastewater network. Several checks in
locations where no leaks were present were carried out, causing delays in the repairs.
Finally, it was established there was no potable water spill in the wastewater network.
iii. Social Factors: Most of the residents of Lixouri had evacuated their homes and as a
result the network could not be tested and adjusted for usual operating conditions.
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WASTEWATER NETWORK
After the 2nd event of February 3rd, 2014, the network fatigue and high volume of water in
the wastewater network resulted in serious operational problems, leaks and risks to the public
health. Dedicated groups of experienced engineers and technicians were immediately deployed
to the island to address these problems. Large scale inspections took place to evaluate the
condition of the network. Most of the activities were concentrated in Argostoli and Lixouri.
The mission of the wastewater teams was: “We will not leave until have a complete picture of
the damages and a recovery plan is set.”
The investigation and repair teams arrived in Cephalonia on February 7th and remained
there for six days as shown in Fig. 10.1.12. The investigation and repair team was equipped
with the most recent technological equipment and vehicles in order to achieve its goal, as
shown in Fig. 10.13.
Figure 10.1.12. EYDAP wastewater network mission field personnel arrived on 2/7/14 and worked at the island for six days. Photos by: (a) EYDAP; and (b) GEER/EERI/ATC reconnaissance team.
(a)
(b)
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Mobile unit and robotic camera for imaging assessment of the sewer networks.
Center of Operations
Figure 10.1.13. EYDAP equipment and field personnel for wastewater network.
Camera for Imaging of sewer networks
Mobile Super 2000 water recycling sewer cleaning machine
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Assessment of Existing Conditions - Actions
The investigation and repair wastewater network teams and the General Manager of
Preventative Maintenance Office, Mr. Elias Karambelas, in coordination with the local
agencies immediately assessed the existing conditions and started in-situ as well as video
inspections. More than 4 km of wastewater pipes were inspected in the towns of Lixouri and
Argostoli and 700 m of wastewater pipes were video inspected. Fig. 10.1.14 shows photos
provided by EYDAP from these the field operations. Fig. 10.1.15 present examples of damage
identified using the video inspection information.
To ensure the uninterrupted operation of its network, EYDAP installed advanced telemetry
systems in crucial locations for continuous monitoring of the most important components of
the system. The main components which are continuously monitored since the earthquake are:
elevations, water flows, and pressures.
Figure 10.14. EYDAP equipment and field wastewater network personnel.
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Figure 10.1.15. Video inspection shots (EYDAP, 2014).
CONCLUSIONS
The potable and wastewater networks suffered notable damage mainly due to the 2nd event.
EYDAP responded rapidly and sent field investigation and repair teams to assist with the
assessment and retrofit of the potable and wastewater networks of Cephalonia. At the end of
the field missions, the EYDAP organization achieved their goals of leaving the island ensuring
that: (i) each home was supplied with clean water and (ii) all damage is assessed, a recovery
plan is set and key parameters are continuously monitored.
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10.2 Transportation Road Network INTRODUCTION
The first larger roads were built by the English in the 19th century. In the 20th century
asphalted roads were built, and since 1995 almost all streets connecting villages and beaches
are covered with asphalt. By 2000, the road network was enhanced with the Lixouri bypass
and a 4-lane street south of Argostoli. Currently the most important roads are (Fig. 10.2.1):
Greek National Road 50, commonly Argostoli-Sami Road
Argostoli-Poros Road
Argostoli-Fiskardo Road (with link to Lixouri)
Road linking Poros and Sami
Figure 10.2.1. Main Cephalonia road network (modified from inagiaefimia.com).
This section presents observations related to road transportation network performance and
traffic disruptions during the two seismic events and their aftershocks. In general, the main
road network performed well, with problems mainly in the Paliki peninsula area (Fig.10.2.1).
Following the 2nd event, the authorities preemptively shutdown the horse-shoe shaped
Argostoli-Lixouri main asphalt road. The traffic between the two towns was available only by
ferry boat that was offered free of charge to the commuters.
Area of traffic interruption
Paliki peninsula
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OBSERVATIONS
The performance of the road transportation network was mostly affected by the response
of road embankments and retaining walls and less of the bridges. Overall, the (small) bridges
of the island responded well to the two main events and their aftershocks and none of the
bridges collapsed or suffered severe enough damage to close down traffic. The only exception
was observed in the Havdata bridge ( 38°12'10.30"N, 20°24'16.05"E), where traffic was partly
interrupted due to excessive settlements in both access embankments, as shown in Fig. 10.2.2.
For more details on bridge behavior, see Section 8.5.
Figure 10.2.2. Settlement of western embankment of Havdata bridge, recorded by reconnaissance team members S. Nikolaou and M. Moretti (38°12'10.30"N, 20°24'16.05"E).
The road embankment inventory of Cephalonia includes many, rather short, road
embankments retained by masonry walls and, to a lesser extent, by reinforced concrete walls.
The response of the embankments, as described in Section 8.6, was satisfactory, meaning that
the roadway network had partial traffic interruption immediately following the two events.
Some notable exceptions that affected traffic include severe damage of the access road to
Myrtos beach due to major rockfalls (38°20'16.20"N, 20°31'56.34"E) and extensive cracking
of the embankment (38°10'42.84"N, 20°24'2.96"E and 38°10'39.79"N, 20°23'50.90"E) that
affected the whole width of the road connecting the Chavriata and Vouni villages (see Section
8.4). There are several locations in the Paliki peninsula area, where moderate damage occurred
at road embankments mostly related to sliding within the embankment material as was
observed in the asphalt road (38°14'17.17"N, 20°25'44.30"E) joining the Aghios Dimitrios and
~ 30 cm
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Livadi villages (see Section 8.6.1). Figure 10.2.3 presents the large downslope displacement
of a circular sliding mass in clayey soil on the order of 40 cm in the vertical direction that
affected a country road embankment north of Soullari village. Note that a detailed map with a
list of towns with their coordinates can be found in Section 2.2.
Figure 10.2.3. North of Soularoi road embankment sliding, as viewed from the pavement (38°11'21.51"N, 20°24'45.80"E).
Moderate roadway embankment damage was also related to total collapse of the masonry
walls and was recorded along the main asphalt road connecting Argostoli to Lixouri, and to the
NW of the village of Kardakata. Figure 10.2.4 shows the collapsed masonry wall which had
supported the road embankment, as seen from the downhill side after the 2nd event. In addition,
there were numerous road embankments along the eastern portion of the main asphalt road
connecting Argostoli and Lixouri which suffered minor longitudinal cracks and small
settlements of the asphalt pavement that caused only some local traffic diversions.
Figure 10.2.4. Masonry wall collapse in NS direction of Kardakata road embankments after 2nd event (38°17'34.61"N, 20°27'8.16"E).
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Traffic problems were caused not only by damage in bridges and road embankments, but also
due to rockfalls and slope instabilities which, in most cases, partially covered the pavement
interrupting traffic as shown on Fig. 10.2.5 from the Aghia Thekla village road (38.25°N,
20.3833°E). Several rockfalls were observed north of Argostoli bay (e.g., 38°17'13.43"N,
20°26'52.89"E) and on the road from Argostoli to Sami (38°12'20.47"N, 20°36'25.76"E).
Figure 10.2.5. Rockfalls in Aghia Thekla village road (38.25°N, 20.3833°E from inkefalonia.gr).
Figure 10.2.6. Rockfalls at main asphalt road connecting Lixouri to Argostoli. Web photo from madata.gr after the 1st event.
The most severe problems caused by rockfalls were observed at the main asphalt road
connecting Lixouri to Argostoli (Fig. 10.2.6). Espectially the eastern portion which was closed
to traffic for at least 15 days (since the 1st event, 1/26/14, and at least one week after the 2nd
event, i.e. at least until 2/10/14) due to concerns of loose rocks falling on the pavement during
aftershock activity. The road was uninterruptedly cleaned from debris during the shutdown
period, and especially after intense aftershocks when additional minor rockfalls were recorded.
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Along village roads, damage on buildings and retaining walls caused traffic interruptions,
since these roads are very narrow. Examples of building damage-related closed roads were
found in Havdata (38°12'14.80"N, 20°23'10.03"E) and Kourouklata villages. The retaining
wall of The Virgin Mary church (Fig. 10.2.7) at Chavriata (38°10'57.32"N, 20°23'14.48"E)
caused road closure (detailed observations on retaining walls are provided in Section 8.3). At
these locations local authorities used road safety cones and “do not cross” lines to locally divert
traffic. Debris collection from roads was in progress when our reconnaissance teams visited
the island and no retrofit work was underway due to concerns of aftershock activity.
Figure 10.2.7. Collapse of masonry wall at courtyard of The Virgin Mary church at Chavriata, which caused local traffic disruption (38°10'57.32"N, 20°23'14.48"E).
Figure 10.2.8. Traffic disruption due to nonstructural elements damage in Krasopatera Street, Lixouri (38°11'36.81"N, 20°26'11.42"E).
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Nonstructural elements damage, including massive chimneys of large quantities roof tiles,
interrupted traffic in urban areas. When the GEER reconnaissance terms visited the island only
some of the debris had been removed from the roads to allow for pedestrian crossing, and in
most cases it was still in place (e.g., in the narrow back-streets of Lixouri). An example is
shown on Fig. 10.2.8 at Krasopatera Street in Lixouri (38°11'36.81"N, 20°26'11.42"E).
In conclusion, the road transportation network of Cephalonia was not severely affected by
the earthquakes. The effects were smaller after the 1st event and were aggravated after the 2nd
one. Traffic was interrupted in the Paliki peninsula area and some problems were recorded on
the eastern portion of the main asphalt road connecting Argostoli to Lixouri. Noteworthy traffic
problems in the rest of the island were very scarce. Traffic disruptions were mostly related to
damage of the transportation infrastructure (road embankments, with or without masonry
retaining walls), and less to falling debris (rockfalls, or collapse of neighboring buildings and
retaining walls). In general, the local authorities were able to divert the traffic where required.
The only occasion where severe traffic problems occurred was during the preemptive shutdown
of the Argostoli-Lixouri main asphalt road after the 2nd event, which was substituted by the
free-of-charge ferry boat service between the two ports.
CHAPTER 11
Structural Observations
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Report Version 1
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11.1 Main Structural Observations INTRODUCTION
During the two main seismic events of January 26th, 2014 (Mw 6.1) and February 3rd, 2014
(Mw 6.0), damage occurred to a number of structures. Most of the structural damage was
observed during the 2nd event and was primarily concentrated in the Paliki peninsula area (Fig.
11.1.1), on the western part of the island. This observation can be attributed to pre-existing
damage which many structures already had suffered during the 1st event, in combination with
the very high ground motions recorded in the Paliki peninsula area during the 2nd event. The
main villages visited by the reconnaissance teams after the 2nd event include Aghios Dimitrios,
Livadi, Vilatoria, Aghia Thekla, Kalata, Monopolata, Kaminarata, Mandourata, Favata,
Havdata, Chavriata, Vouni and Manzavinata (Fig. 11.1.1).
Figure 11.1.1. Areas visited by the reconnaissance teams where most of structural damage occurred.
PALIKI Peninsula
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MAIN OBSERVATIONS
In general, the buildings on the island behaved well, considering the intensity of the
earthquake which had ground accelerations of up to 0.75 g with Spectral Accelerations (SA)
exceeding 2.5 g for periods within the 0.3-second range. This range must have been close to
the period of most of the buildings, since the local code restricts building height to three stories.
At the area around the epicenter, most of the buildings are low-rise with a Reinforced Concrete
(RC) frame and brick infill walls. The majority of these buildings suffered negligible or minor
damage at the brick infill walls, which, in some cases, were separated from the RC frame. The
overall satisfactory structural performance can be attributed to good construction quality,
especially of the infill walls which, in most cases, were able to withstand the largest portion of
the seismic loads without cracking. Figure 11.1.2 shows an example of a building in Livadi
(Fig. 11.1.1), which suffered negligible damage despite the fact neighboring structures suffered
significant damage. Except from the dislocation of several roof tiles and possible displacement
of the solar panel, there is no evidence of any other damages (including light cracks in the brick
infill walls). The dislocation of the roof tiles, observed in many structures in the meioseismal
area, is a likely result of the high accelerations that occurred.
Figure 11.1.2. A two-story RC building in Livadi which performed well, despite the fact that at this area where several buildings suffered significant damage. Evidence of high accelerations if the dislocation of roof tiles observed in several structures throughout the meioseismal area.
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However, several buildings suffered medium to severe damage. In general, these buildings
belong to one of the following categories:
Reinforced Concrete (RC) buildings designed under older seismic codes. Some
characteristics that possibly have contributed to their damage are: the large tie (stirrup)
spacing (> 300 mm), lack of confinement at beam-column joints, and poor detailing.
Examples shown in the photos of Fig. 11.1.3 (coordinates 38o13'45.60'', 20o25'47.40'').
RC buildings with a soft story at the ground level. Example on Fig. 11.1.4 in Aghios
Dimitrios (38o14'36.51''N, 20o25'41.91''E).
Mixed structural systems which usually include a masonry ground floor and a reinforced
concrete upper floor, built in phases over the course of several years. An example is shown
in Fig. 11.1.5 (GPS coordinates: 38.229444, 20.429722.)
Old masonry buildings which survived the 1953 earthquakes and had then been repaired
(Fig. 11.1.6), including several churches discussed separately in a Section of this Chapter.
RC buildings with masonry infill walls had minor damage on the RC structural frame and
damage in the masonry infill walls. An example is shown in Fig. 11.1.7.
Figure 11.1.3. Damage of 2-story RC building in Aghios Dimitrios designed with older codes (GPS coordinates: 38.229444, 20.429722): (a,b) after 1st and 2nd events; (c,d) beam-column detail of (b).
(a)
(c) (d)
(b)
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Figure 11.1.4. Significant damage to the soft story columns of a two-story RC building in Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E). No damage was observed at the upper floor.
Figure 11.1.5. Collapse of the masonry ground floor of a two-story building in Aghios Dimitrios. The upper floor is a reinforced concrete frame, added several years after initial construction (GPS coordinates: 38.229444, 20.429722).
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Figure 11.1.6. Partial collapse of a heritage masonry building in Samoli, close to Livadi village (see Fig. 11.1.1), which was probably built during the 17th century. The building had survived the 1953 earthquakes with some damage which had subsequently been repaired.
Figure 11.1.7. Severe damage of brick infill walls of a two-story RC building in Livadi (Fig. 11.1.1). The frame suffered only minor damage (38°13'48.19"N, 20°25'53.20"E).
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Although most buildings performed well, a large number of nonstructural components
collapsed. While details can be found further into this Chapter (and in Chapter 9), typical
examples of nonstructural architectural failures are shown on Fig. 11.1.9. The photos show
representative failure of numerous masonry fences and pergolas that may be attributed to lack
of seismic specifications or poor quality control during construction, which does not require
professional engineering inspection.
Figure 11.1.8. Examples of nonstructural architectural components failure: (a) overturning of a masonry fence in Lixouri; (b) collapse of a pergola in Livadi.
In general, damage or failure of nonstructural components was evident in the strongly-felt
areas of the island, exposing the people to life threats and resulting in significant interruption
of the function and impacts on the economy of the island. This earthquake reconnaissance
provides detailed documentation of both acceleration- and displacement-sensitive
nonstructural components in Section 11.9 and Chapter 9 of this report. The detailed information
collected in the field, together with the several recorded strong ground motions in the
immediate vicinity of the information, presents an excellent opportunity to enhance our
knowledge on the behavior of all types of nonstructural components and develop simple,
engineering and common-sense, solutions to minimize their seismic risk exposure.
(a)
(b)
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11.2 Building Inventory and Construction Types
The majority of the structures of Cephalonia were rebuilt following the catastrophic 1953
earthquakes that destroyed more of the building stock. Currently, the building inventory can
be grouped into four major categories according to their load bearing system:
I. One- to two-story non-monumental / non-landmark masonry buildings: These can be
further subdivided into two groups based on their location:
a. Buildings constructed with clay, stone, or concrete bricks with better quality mortar,
mainly found in the towns of Argostoli and Lixouri.
b. One-story masonry buildings with walls composed of roughly treated stones and low-
strength clay mortar. There is only few of those buildings in small villages, survivors of
the 1953 earthquakes. After the 1953 events, their use changed to barns, stables, or other
auxiliary structures, or they were simply abandoned without retrofit or maintenance.
II. Reinforced Concrete (RC) buildings: Located throughout the island, these buildings were
generally constructed after the 1953 earthquakes following modern seismic codes, varying
from one to four stories in height. Their load-bearing system is reinforced concrete frames
and shear walls and their top has wood framed roofs. Some of those buildings can be
classified as monuments, especially in the largest towns of Argostoli and Lixouri.
III. Masonry monumental and other cultural heritage buildings: These are mainly churches or
schools with one or two stories, constructed using traditional seismic-resistant techniques.
IV. Other buildings and structures: This category includes wood framed buildings and stone or
Reinforced Concrete (RC) bridges.
The observed behavior of selected types of the above buildings have dedicated sections this
report, such as bridges and churches in 8.5 and 11.8, respectively.
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11.3 Damage Assessment
Damage assessment survey efforts were led by the Greek Seismic Rehabilitation Agency
(YAS or ΥΑΣ in Greek for “Υπηρεσία Αποκατάστασης Σεισμοπλήκτων”). A temporary field
office was established in the facilities of the Technological Educational Institute (TEI) of the
Ionian Islands, a public building in Argostoli, to organize the inspections and emergency
interventions. The inspections were mostly performed by teams of structural engineers who
work for public agencies. A Rapid Assessment phase was performed immediately after the 1st
event, followed by a Detailed Assessment phase.
Rapid Assessments have a screening role to quickly distinguish between safe and unsafe
buildings. They are performed either upon the owner’s request, or directly by YAS initiative
for buildings where structural damage is evident from the structure’s exterior. The process
involved teams of two engineers each, who would fill the Rapid Inspection Forms and describe
key characteristics such as number of stories, load bearing system and use. The teams would
then assign a color: Green, for safe buildings, or Yellow for buildings which should
temporarily be evacuated. Green-tagged buildings had minor damage only, e.g., a small
number of hairline cracks in the masonry infill or bearing walls, isolated hairline cracks in
Reinforced Concrete (RC) structural elements perpendicular to the element’s axis.
Figure 11.3.1. Typical degrees of damage in vertical structural elements of Reinforced Concrete (RC) structures according to YAS (modified from (YAS, 2014).
For yellow-tagged buildings, a Detailed Assessment phase followed by teams of three
engineers, in which buildings are tagged as: Green (safe for use), Yellow (not safe for use
which need retrofitting) and Red (not safe for use, decision to repair or demolish pending
MINOR
DAMAGE
SERIOUS
DAMAGE
SEVER
E DAMAGE
JOINTS
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detailed engineering evaluation). Sketches of typical degrees of damage in vertical structural
elements of RC buildings, ranging from minor to severe, are presented in Fig. 11.3.1 (modified
from YAS, 2014).
Figure 11.3.2. Results of Rapid Assessment and Detailed Assessment phases. In the Rapid Assessment, 31% or 1505 buildings were found unsafe to occupy. The Detailed Assessment of the yellow-tagged buildings found 46% (1265) safe, 48% (1325) temporarily unsafe, and 6% (180) unsafe and pending detailed evaluation of whether to repair or demolish.
Figure 11.3.2 shows color-tagging based on the initial Rapid Assessment and the Detailed
Assessment that followed according to data collected by the Hellenic Earthquake
Rehabilitation Services (HERS).
In the Rapid Assessment phase, 4,865 buildings were inspected, mostly in the Paliki
peninsula with 31% or 1,505 buildings yellow-tagged or unsafe to immediately occupy.
During the Detailed Assessment phase, 2,770 buildings were inspected, including the
yellow-tagged buildings from the Rapid Assessment phase and others that required further
investigation. During this inspection, 1,265 buildings (46%) were deemed safe (green), 1,325
(48%) were considered temporarily unsafe (yellow), and 180 (6%) were unsafe (red). Of the
2,770 buildings, 1,167 were Reinforced Concrete (RC) structures that were classified by 60%,
39% and 1% as green, yellow and red, respectively. 765 buildings were masonry structures
with 29%, 54% and 17% deemed as green, yellow and red, respectively and 783 were hybrid
structures, with 40%, 56% and 4% considered as green, yellow and red, respectively. Finally,
85 buildings were of other types with 48%, 41% and 11% tagged as green, yellow and red.
The results of the Detailed Assessment broken down by building type are presented in Fig.
11.3.3. Considering the 180 red buildings alone, 5% were made of reinforced concrete, 73%
were masonry, 17% were hybrid concrete-masonry constructions, and 5% were of other types.
Rapid Assessment
Safe
Not Safe
Detailed Assessment
SafeNot Safe (retrofit)
Not Safe (repair or demolish)
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It can be concluded from these statistics that the masonry buildings suffered the most. Of the
regions of Cephalonia mostly affected by the earthquake, 76% of the red and 60% of the yellow
buildings were located on the Paliki peninsula. When considering use, 52% of the red buildings
were farm storage, warehouses, stables, etc. or had been abandoned, 39% were residential
buildings and 9% were commercial buildings such as offices.
Figure 11.3.3. Detailed assessment of 2,770 buildings: 1,167 were RC (60, 39, 1% tagged green, yellow, red); 765 were masonry (29, 54, 17% tagged green, yellow, red); 783 were hybrid (40, 56, 4% tagged green, yellow, red); and 85 were other (48, 41, 11% tagged green, yellow, red).
Figure 11.3.4. Types of the 180 red-tagged buildings of the Detailed Assessment: 5% reinforced concrete, 73% masonry, 17% hybrid concrete-masonry, and 5% other types.
Detailed Assessment
Concrete Structure ‐ Safe
Concrete Structure ‐ Unsafe
Concrete Structure ‐ Repairable
Masonry Structure ‐ Safe
Masonry Structure ‐ Unsafe
Masonry Structure ‐ Repairable
Hybrid Structure ‐ Safe
Hybrid Structure ‐ Unsafe
Hybrid Structure ‐ Repairable
Other Structure ‐ Safe
Other Structure ‐ Unsafe
Other Structure ‐ Repairable
Red buildings
Reinforced Concrete
Masonry
Hybrid
OtherMASONRY
OTHERCONCRETE
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The Greek Government was quick to respond in the aftermath of the disaster. Shortly after
the main shocks it announced that aid would be offered to repair temporarily unsafe for use
(yellow) or reconstruct dangerous for use (red) buildings. 80% of the aid will be in the form of
free assistance and the rest will be in the form of an interest-free loan to be paid back over a
period of 15 years. The government will pay up to €1,000/m2 to rebuild residential buildings
up to 120 m2 in area. For business premises and public buildings, government contribution will
be up to €500/m2 for up to 120 m2 in area. Churches will receive up to €800/m2 regardless of
area. Finally, farm storage, warehouses, stables, etc. will receive up to €250/m2 for up to an
area of 120 m2. For repairing damage, the government will pay up to €450/m2 up to an area of
120 m2 for damage to load bearing and non-load bearing elements. This will be up to €250/m2
for areas of up to 120 m2 for non-structural damage. Funds will be provided in successive
instalments paid upon completion of specific stages of the work. For owners of buildings
classified as yellow or red, the government will subsidize rents to owners for a period of two
years. For tenants, this will be for up to six months. As a first estimation, the total cost of
replacing or repairing only the damaged buildings will be of the order of €100 to 200 million.
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11.4 Typical Damage Patterns by Construction Type
Even in the region affected the most by the 2014 earthquake events, there is a large number
of buildings which upon our inspection had no obvious or even minor damage, such as small
cracks separating infill walls from the reinforced concrete bearing elements. There are,
however, buildings that were severely damaged, as well as buildings that collapsed. In this
section, we present typical observed damage patterns, along with some qualitative
interpretation of the damage, wherever possible.
Detailed assessments for some of the collapsed or severely damaged buildings will be
presented in future revisions of this report. These (currently underway) assessments take into
account actual construction and design drawings provided to our teams, recorded ground
motions and details observed in the field. At this stage, only general observations and
qualitative interpretation of some damaged buildings can be provided.
MASONRY BUILDINGS (POST-1953 GOVERMENT-BUILT)
Buildings of this category typically have a single story and are constructed of cement
blocks (Fig. 11.4.1), with Reinforced Concrete (RC) vertical ties/columns (at least at the
corners of the structure), horizontal RC ties/beams (at least at the top of the walls), and timber
roofs (see detail of Fig. 11.4.2). Most of the masonry buildings discussed in this category
behaved adequately, suffering little to no damage.
Figure 11.4.1. Typical single-story masonry building constructed after the 1953 earthquake.
This category also includes the "Arogi" houses ("relief" in English), built with the intent of
temporary housing by the government between 1953 and 1959, but are used until now. Several
of the Arogi houses experienced damage, mostly in cases where the owners had expanded their
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homes by adding masonry or reinforced concrete additions. This practice is fairly common on
the island, with houses being built and expanded in several phases during many years to
accommodate younger generations of the same family. Expansions were made horizontally (in
plan, see Fig. 11.4.1) or vertically (in elevation, i.e., by adding a floor).
Figure 11.4.3 shows an example of an Arogi house built in phases, where a portion of it
failed. In this case, the original (1950’s) timber roof of the structure was removed and
substituted with RC slab to accommodate a RC frame with clay brick masonry infills as a 2nd
story, added in 1978. The added 2nd story did not appear to be damaged, but the masonry ground
floor collapsed. The failure was probably caused due to excessive loading of the original
ground floor. Sections 11.5 and 11.6 provide more cases and information on Arogi houses.
Figure 11.4.2. Smooth steel bars of a vertical Reinforced Concrete (RC) tie, typical for RC building construction during the 1950's and 1960's.
Figure 11.4.3. (a) Collapse of 1st story of a masonry Arogi building where a 2nd story was added more than two decades after the original construction. (b) Cement block masonry reinforced with vertical and horizontal RC ties (GPS coordinates 38o13'49.80''N, 20o25'49.80''E.)
(a) (b)
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MASONRY BUILDINGS (PRE-1953 OR POST-1953 PRIVATELY-BUILT)
One or two-story buildings constructed of stone or brick masonry built before 1953 or post-
1953 by private entities (unlike the government-built Arogi houses), can be found in Lixouri
and in neighboring villages. Typical observed damage is shown in Figs. 11.4.4 to 11.4.9.
Figure 11.4.4. Typical bi-diagonal (shear) cracks in a masonry wall.
Figure 11.4.5. Shear failure of bearing walls and out-of-plane failure (corner of building and top of walls) of a single-story stone masonry building. Note the double-leaf construction of bearing walls and local disintegration of the outer leaf.
Figure 11.4.6 shows typical three-leaf stone masonry construction with two exterior stone
masonry leaves and intermediate filling material of poor quality. Observed damage includes
separation of leaves, which probably occurred before the earthquake, and partial collapse of
the wall (more extensive for the exterior leaf) due to out-of-plane bending.
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Figure 11.4.6. Typical three-leaf stone masonry construction. Damage includes separation of leaves, probably present before the earthquakes, and partial collapse of the wall due to out-of-plane bending.
This category includes churches and schools, some of which are considered landmarks.
The behavior of these particular structures are discussed in detail in following sections of this
chapter. Indicatively, damage examples on churches are presented in Figs 11.4.7 to 11.4.9.
Figures 11.4.7 and 11.4.8 present severe damage observations after the 2nd event in the
masonry church of Virgin Mary in Chavriata (38°10'57.52"N, 20°23'13.61"E). The damage
pattern is affected by the damage after the 1st event and eventual collapse after the 2nd event of
the stone masonry retaining wall as described in detail in Section 8.3.
Figure 11.4.7. Structural damage of the Virgin Mary masonry church in Chavriata (38°10'57.52"N, 20°23'13.61"E) after the 2nd event, affected by the stone masonry retaining wall collapse (Section 8.3).
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The shear and vertical cracks shown on Fig. 11.4.8 may be due to the displacement of the
central part of the church towards the failed retaining wall. Prior to the 2014 events, some
seismic retrofit was made using RC jackets shown on Fig. 11.4.8a (below the window).
However, it seems that RC jackets were not installed throughout the entire perimeter of the
church (Fig. 11.4.8b), and the contribution (positive or negative) of this intervention to the
overall behavior of the church cannot be assessed at this stage without further data.
Figure 11.4.8. Observed cracks possibly due to church displacement towards the failed retaining wall. (a) Seismic retrofit RC jacket below window; (b) absence of jackets (38°10'57.52"N, 20°23'13.61"E)
Typical shear and out-of-plane damage in the stone masonry church of Aghia Thekla
(38°14′41″N 20°23′06″E) is shown on Fig. 11.4.9.
Figure 11.4.9. Typical shear and out-of-plane damage in the northeast corner of the stone masonry church of Aghia Thekla (38°14′41″N 20°23′06″E).
For details and inventory of the Cephalonia churches, see Section 11.8 of this Chapter.
(a) (b)
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REINFORCED CONCRETE (RC) BUILDINGS
The Reinforced Concrete (RC) buildings cover the majority of structures in Cephalonia and
they overall behaved well, regardless of their year of construction and corresponding seismic
code generation followed for their design (see details in Section 11.5).
The most common type of damage, observed in numerous cases, was the detachment of the
infill walls from the surrounding concrete beam-column frames. This damage raised much of
the public concern since it was a main visible damage pattern for many RC structures. After
detailed inspections, no cracks were observed at the RC structural elements of almost every
building checked. Additionally, in most cases no diagonal cracks were observed at the infill
walls. It was also noted by the reconnaissance teams that typically two horizontal concrete ties,
sometimes dowelled into the concrete column-shear wall, were constructed along the height of
the infill wall. Due to the stiffness of the infill walls, the inter-story drift was small, possibly
explaining the absence of diagonal cracks.
In some RC buildings, damage of structural elements and/or in infill walls was observed
mainly along the road north of Lixouri (towards Aghios Dimitrios and Livadi) with the most
serious damage in and around the village of Livadi. However, in most cases it was found that
the buildings were reinforced with an adequate number of steel bars and stirrups resulting in
no observed failures due to the inelastic elongation of steel bars. Observed failures were mainly
due to crushing of concrete and diagonal tension. Examples of damage patterns and failures
are illustrated in the following figures 11.4.10 to 11.4.20.
Figures 11.4.10 to 11.4.12 show one of the most striking collapses of the 2014 events: the
failure of the intermediate story of a three-story RC building that was completed in 2007. The
damage of the RC bearing elements on the ground floor (Fig. 11.4.11a) may be attributed to
shear failure of a shear wall. On one side the infill walls failed in their plane, while in the
perpendicular direction the infill walls collapsed in the out-of-plane direction. An indication of
different intensity of ground motion in the main directions of the building is presented in Fig.
11.4.11b. Poor behavior of infill walls with disintegration of vertically perforated bricks is
shown on Fig. 11.4.12. The negative effect of “mortar keys” is evident. The RC tie beams
(typical for enclosures throughout the country) did not prevent the occurrence of horizontal
cracks along the tie beam/brick wall interface. This case history is under investigation and
conclusive remarks regarding the collapse cannot be made until more data and analysis results
become available.
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Figure 11.4.10. Collapse of intermediate story of 3-story RC building completed in 2007. (GPS coordinates: 38.258888, 20.424444).
Figure 11.4.11. Building of Fig. 11.4.10 (GPS coordinates: 38.258888, 20.424444): (a) damage of RC bearing elements on ground floor; (b) indication of different ground motion in main building directions.
(a) (b)
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Figure 11.4.12. Poor behavior of infill walls with disintegration of vertically perforated bricks observed at the building of Fig. 11.4.10 (GPS coordinates: 38.258888, 20.424444).
A two-story building in Aghios Dimitrios with load bearing system designed to
accommodate at least three stories as indicated by the extending steel bars extending beyond
the columns top is shown on Fig. 11.4.13 (38o14'36.51''N, 20o25'41.91''E). The ground floor
columns failed due to soft story without infill walls. Figure 11.4.14 shows the crushing of
concrete and fracture of the closely spaced, single rectangular hoops of the columns.
Figure 11.4.13. Two-story building that experienced typical soft story damage in Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E).
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Figure 11.4.14. Crushing of concrete and fracture of closely spaced, single rectangular hoops of the columns of the two-story building in Fig. 11.4.13 (38o14'36.51''N, 20o25'41.91''E).
Figure 11.4.15. Damage of 2-story RC building in Aghios Dimitrios (38°13′45.6″N 20°25′47.4″E): (a) shear cracks and separation of infills after 1st event; (b) failure of columns and joints after 2nd event; (c, d) detailing with single rectangular largely spaced hoops; and (e) detail of beam-column joint failure.
(b)(a)
(a) (b)
(c)
(d)
(e)
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The damage of a two-story RC building in the village of Aghios Dimitrios (38°13′45.6″N
20°25′47.4″E) following both events is presented on Figures 11.4.15. The 1st event caused
shear cracks at the middle column of the façade next to the door and separation of infills from
the surrounding frames and shear failure of enclosures (Fig. 11.4.15a). Following the 2nd event
failure of columns and beam-column joints along both building axes was observed (Fig.
11.4.15b). The deformed shape of RC elements suggests that they likely failed after the
collapse of the infill walls (already separated from the frames and severely damaged during the
1st event). Evidence of poor detailing of the columns with single rectangular largely spaced
hoops is shown on Figs. 11.4.15c, d and detail of the failure at a beam-column on Fig. 11.4.15e.
Figure 11.4.16. Residential 1962 "Arogi" public housing complex in Lixouri (GPS coordinates 20.434256, 38.21159) with: (a) extensive damage of infill walls and structural elements; (b) failure of a column. Note large spacing of single rectangular hoops.
Figure 11.4.17. Single story building in the public housing complex of Fig. 11.4.16 without earthquake resisting frames: (a) damage to the columns; (b) detail of slab-column joint.
The public 1962 "Arogi" residential housing complex in Lixouri (GPS coordinates:
38.211666, 20.433611) had extensive damage of the infill walls and of the structural elements
(a) (b)
(a) (b)
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(Fig. 11.4.16). The adjacent single-story building, part of this complex, had no earthquake
resisting frames and suffered severe damage to the columns and the slab-column joint (Fig.
11.4.17). Nearby, a 2-story residential building of 1978 had severe damage on the ground floor
and minor damage on the upper story (Fig. 11.4.18, GPS coordinates 38.211567, 20.434134).
Figure 11.4.18. (a) Two-story residential buildings of 1978 with severe damage on the ground floor and minor damage on the upper floor; (b, c): Details of damage (coordinates 38.211567, 20.434134).
Failures of the upper part of RC belfry of churches were observed (see Section 11.8 for Cephalonia
churches observations). As an example, Fig. 11.4.18 shows belfry damage at Aghios Ioannis church of
Kourouklata (GPS coordinates: 38.242119, 20.473977) that could be attributed to stiff upper part,
flexible lower part (poor detailing of rather short columns).
Figure 11.4.19. (a) Failure of upper part of the RC belfry of Aghios Ioannis church in Kourouklata (GPS coordinates: 38.242119, 20.473977); (b) detail showing poor detailing of rather short columns with stiff upper part, flexible lower part. Failure and crushing of concrete.
(a) (b)
(b)
(a)
(a) (b)
(a)
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Figure 11.4.20. Typical infill wall construction from the 1960’s that incorporates reinforcement with vertical and horizontal rebars that have likely contributed to satisfactory performance of many buildings of that time. This photo shows a building in Lixouri during rehabilitation.
Overall, RC buildings performed well and appear to have redundancy and reserved strength
of individual structural members. The reconnaissance teams identified as beneficial factors the
structural system regularity, good construction quality, and contribution of the infill walls with
vertical and horizontal rebars (Fig. 11.4.20).
TIMBER BUILDINGS
The existing timber buildings and roofs performed satisfactorily, with the timber roof
being independent from the main structural system. An exception is shown in Figure 11.4.21,
where the superstructure displaced relatively to the foundation.
Figure 11.4.21. Two-story timber residential structures in Aghios Dimitrios. The only damage observed was a crack at the interface of the wood frame/walls with the concrete base slab.
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11.5 Structural Behavior Based on Seismic Codes GREEK BUILDING CODES
A brief historic review of the Greek aseismic code helps us better understand the behavior
of the different building types during the 2014 earthquake events in Cephalonia. Greek seismic
codes have evolved as major seismic events have been observed over the past decades. The
different generations of codes are:
1. 1959: The first seismic code became effective in 1959, a result of the 1953 Cephalonia
earthquakes which also caused destruction in the neighboring Ionian islands of Zante
(Zakynthos) and Ithaca. This code was based on elastic design and simplified assumptions
of the dynamic behavior of buildings. It prescribed a design horizontal force based on the
building mass, seismicity zone, and soil category. Three seismicity zones were included,
with Cephalonia being in the zone of highest seismicity of seismic factor ranging between
0.08 to 0.16g, depending on soil conditions.
Prior to 1959, buildings were generally designed for vertical loads only using the 1st
building code for Reinforced Concrete (RC) of 1954, an allowable stress design code which
did not include any detailing for ductile behavior. However, in the seismic-prone Ionian
Islands, some empirical design concepts were applied which allowed for a certain amount
of lateral resistance. It has been estimated that the inherent local ductility of RC elements
in buildings constructed according to the 1954 and 1959 codes is between 1.5 and 2.0.
2. 1984: Additional seismic design provisions were incorporated in the existing code as a
result of the disastrous earthquakes in the two largest Greek cities, Thessaloniki (1979) and
the capital Athens (1981). Among other provisions, capacity design of columns in bending
and specific detailing for local ductility were introduced.
3. 1995-2000: The New Greek Aseismic Code (NEAK) and the Code for Reinforced Concrete
Design (NEKOS) became in effect in 1995 and were finalized in 2000 (with an amendment
in 2003) as EAK and EKOS, respectively, based on predecessors of the Eurocodes with
modern concepts for ductility. A global behavior factor of 3.5 was introduced for RC frame
structures (by which the horizontal seismic force is divided). In addition, an alternative
design for elastic behavior was allowed. Currently in effect, EAK-2000 provides a seismic
zoning map (Fig. 11.5.1) for rock conditions with three zones I, II, III with reference ground
acceleration ag of 0.16, 0.24, and 0.36 g, respectively, with Cephalonia in Zone III.
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4. 2012: Eurocode EC-8 (2008) became in effect concurrently with the Greek codes EAK and
EKOS in 2012, introducing more demanding detailing provisions. The seismic zoning of
Greece according to the Eurocodes is the same as the one in EAK (Fig. 11.5.1).
Figure 11.5.1. Current seismic zoning of Greece (EAK, 2000) for ground type A (rock) with zones I, II, III of reference ground acceleration ag of 0.16, 0.24, and 0.36 g. Cephalonia is in Zone III.
EC-8 defines the seismic hazard using the regionally zoned ground acceleration ag for
ground type A (rock with shear wave velocity Vs > 800 m/s) for an event with approximate
return period of 2,500 years, and modifies for site conditions (ground type). Table 11.5.1
presents the definition of ground types according to EC-8. Site factors, S, associated with
each ground type and average shear wave velocity at the top 30 m (Vs,30) are applied to
produce design spectra for the various ground types. EC-8 code-based elastic acceleration
spectra are presented on Fig. 11.5.2. The ground types are presented in Table 11.5,
including comparisons with the equivalent ASCE 7-05 site classification (the basis of
International Building Code IBC-09), discussed in detail in Section 8.1.
Cephalonia
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Table 11.5.1. Eurocode EC-8 and ASCE7-05 ground types and site classification.
Figure 11.5.2. Cephalonia elastic acceleration response spectra for various ground types based on Eurocode EC-8 and the Greek seismic code EAK-2000.
STRUCTURAL SEISMIC DETAILING
Seismic detailing provisions that may have contributed positively to the observed structural
behavior during the 2014 Cephalonia earthquakes include: (i) approximate maximum
allowable spacing of stirrups of 100 mm along the height of vertical bearing elements, and 150
to 200 mm between stirrup legs in cross section. This requirement was introduced in 1984 as
supplementary provision to the 1959 code, and is currently in effect, and (ii) shear walls are
required to have confined columns at both ends based on the current codes. In the 1959 code,
the cross-section of the corner columns should be at least 350 mm on each side for square
columns, and no provisions were included for the detailing of shear walls.
Ground Vs,30 Site Vs,30
Type (m/s) Class (m/s)
A Rock > 800 A Hard Rock > 1,500
B Deep - Very Dense 360 800 B Rock 760 1500
C Deep - Dense to Medium 180 360 C Very Dense Soil / Soft Rock 360 760
D Loose to Medium Dense < 180 D Stiff Soil 180 360
5-20 m thick E Soft Soil < 180
Vs30 same as Type C or D F Liquefiable Soil
EC-8 ASCE7-05
Description Description
E
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COMPARISON WITH 2014 RECORDED GROUND MOTIONS
Figures 11.5.3 and 11.5.4 compare acceleration response spectra recorded ground motions
from the 1st and 2nd events, respectively, with the Cephalonia EC-8 elastic spectra. Details of
the stations are provided in Chapter 7. As discussed extensively in Section 8.1, local site effects
and directivity have likely contributed to high amplification effects that need to be studied
further with pertinent in-situ testing.
Figure 11.5.3. Comparison of elastic response spectra for various ground types, based on current seismic codes (EC-8 and EAK-2000) with spectra of recorded motions from the 1st event of 1/26/14.
Figure 11.5.4. Comparison of elastic response spectra for various ground types, based on current seismic codes (EC-8 and EAK-2000) with spectra of recorded motions from the 2nd event of 2/3/14.
PERIOD, T : sec
0.0 0.5 1.0 1.5 2.0 2.5 3.0
SP
EC
TRA
L A
CC
ELE
RA
TIO
N,
SA
: g
0.0
0.5
1.0
1.5
2.0
EC8 Ground Type AEC8 Ground Type BEC8 Ground Type CEC8 Ground Type DEC8 Ground Type EEvent 1, N-S @ ARG2Event 1, E-W @ ARG2Event 1, N-S @ VSK1Event 1, E-W @ VSK1
PERIOD, T : sec0.0 0.5 1.0 1.5 2.0 2.5 3.0
SP
EC
TRA
L A
CC
ELE
RA
TIO
N,
SA
: g
0.0
0.5
1.0
1.5
2.0
2.5
3.0
EC8 Ground Type AEC8 Ground Type BEC8 Ground Type CEC8 Ground Type DEC8 Ground Type EEvent 2, N-S @ ARG2Event 2, E-W @ ARG2Event 2, N-S @ CHV1Event 2, E-W @ CHV1Event 2, N-S @ LXR1Event 2, E-W @ LXR1
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The recorded spectra far exceeded code-based spectra in the 2nd event, with the exception
of the Argostoli (ARG2) records that are lower, which can be expected since this station is
farther away from the epicenter and is on stiffer site conditions as compared to the other
stations. Modern buildings designed to latest code are expected to have a period in the range
of 0.2 to 0.4 seconds and have experienced maximum spectral accelerations reaching 3 g (at
Chavriata) and 1.5 g (in Lixouri) during the 2nd event.
The resiliency of these structures need to be studied further. The Cephalonia case studies
present an excellent opportunity to analyze and explain good structural behavior of RC
buildings subjected to spectral accelerations more than twice their elastic spectral design
values. The information provided in this report, including structural drawings for a dozen of
structures provided to our teams by their owners, can be used to this end, combined with
pertinent soil testing that can explain site response effects.
STUCTURAL OBSERVATIONS BY DESIGN CODE
Structural observations have been grouped based on the year of construction and
contemporary applicable seismic code. Regardless of the year of construction, building infills
and partitions are typically made of brick masonry that are considered non-bearing elements
and are not taken into account in the seismic design.
Built prior to 1953
Most of the Cephalonia structures were built after the 1953 earthquakes that destroyed most
of the building stock of the island. Buildings constructed as family homes prior to 1953, mostly
found in small villages, typically have load bearing masonry walls and wooden-frame clay-
tiled roofs as shown on Fig. 11.5.5. Most of them are single-story, and if there is a 2nd floor,
wooden floors are used. Many churches on the island also belong in this category, as described
in detail in Section 11.8.
Although these structures were not constructed for seismic loads, the pre-1953 buildings
which still remain on the island have survived not only the 1953 earthquakes, but also a number
of other earthquakes since then. In most cases, their use has been changed in the past decade
from family homes to low-importance occupancy structures used for storage of agricultural
goods or tools. Currently, these buildings have become abandoned or not maintained.
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Figure 11.5.5. Typical pre-1953 masonry buildings in Cephalonia.
Damage observed in the pre-1953 buildings includes diagonal cracks on the bearing walls
and/or partial collapses. In some cases, cracks were formed during previous earthquakes and
were inadequately repaired with a different type of mortar and were aggravated by the 2014
earthquakes. After the 2nd event, many of these structures suffered major damage or collapsed
(Fig. 11.5.5: Chavriata 38o11'0.67''N, 20o22'54.93''E; Havdata 38o12'11.62''N, 20o23'09.01''E).
This observation was recorded in a small number of structures throughout the island and cannot
be attributed to a particular area.
Built 1953-1959 “Arogi” Houses (Arogi = Αρωγή = Relief)
Arogi (relief) houses are single-story individual structures built after the 1953 earthquakes
by the government for temporary use, but have been maintained until now and they are
common in Cephalonia. Observations for these houses are discussed throughout this Chapter.
The Arogi structures are generally rectangular in plan (ranging from 30 to 40 m2, up to 80
m2), made of cinder-block walls with cement mortar encased in RC frames as shown in Fig.
11.5.6. The walls are reinforced with vertical steel bars running through their height typically
every two cinder blocks. In addition, there is some horizontal reinforcement in the walls below
the window openings (with the top of the window located at the RC beam).
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Figure 11.5.6. Pre-1953 masonry construction: (a) partial collapse of a Chavriata house (38o11'0.67''N, 20o22'54.93''E), 50 m from station CHV1; (b) collapse of building Chavriata; (c) collapse of 2-story house in Havdata (38o12'11.62''N, 20o23'09.01''E); (d,e) partial collapse of secondary-use buildings; and (f,g) adjacent buildings with no damage in (g) that had reinforced concrete ties at the top.
This type of construction is light, simple, quick and economical to build and has high
resistance to seismic forces. In cases where no additions/expansions were made to an Arogi
house, the structure behaved well during the 2014 earthquakes as they did in the preceding
events of lower intensity in the past 50 years. Few structures, however, did suffer some damage
expressed as visible diagonal cracks in the infill walls.
Arogi houses often include multiple extensions constructed over the past decades with
different construction methods. Typically horizontal extensions were made first (usually after
1959), followed by vertical 2nd-story additions (usually between the 80’s and 90’s). The
performance of these structures is discussed in Section 11.6.
(a) (b) (c)
(d) (e)
(f) (g)
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Figure 11.5.7. Arogi-type buildings post-1953: (a) typical Arogi house in Livadi; (b) Chavriata old school (38o11'00.67''N, 20o22'54.93''E) with cinder block construction with recording station CHV1; (c) details of encased reinforced cinder walls with cement based mortar.
Interestingly, the old school building in Chavriata (38o11'00.67''N, 20o22'54.93''E) shown
on Fig. 11.5.7b, had the CHV1 station accelerometer installed that recorded a Peak Ground
Acceleration PGA of 0.75·g with Spectral Acceleration (SA) of almost 3 g during the 2nd event
(Fig. 11.5.4). The construction of this house is typical of the Arogi type (i.e., load carrying
steel-reinforced cinder block walls). In a radius of 45 to 52 m from the CHV1 station (as shown
on Fig. 11.5.8a), the following observations were made: (i) Arogi house of Fig. 11.5.7c (52 m
away from the CHV1); (ii) partially collapsed masonry house showed of Fig. 11.5.8b; (iii) 2-
story structure of Fig. 11.5.8b with no damage. Figure 11.5.9 shows the exterior and interior
damage of the old school building in Chavriata, where CHV1 is located.
Cement‐based mortar
Reinforced Concrete frame
Vertical reinforcement running through cinder
block walls
(a) (b)
(c)
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Figure 11.5.8. (a) Locations of CHV1 accelerometer in Chavriata old school building (38o11'00.67''N, 20o22'54.93''E) and four buildings within 45 to 52 meters around it; (b) three buildings east of CHV1: partially collapsed stone house, Arogi house, and two-story RC building.
(a)
(b)
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Figure 11.5.9. Exterior (top) and interior (bottom) damage of the old school building in Chavriata (38o11'00.67''N, 20o22'54.93''E) where the CHV1 accelerometer is located.
Built between 1959 and 1984 (1959 seismic code)
Buildings built between 1959 and 1984 were designed based on an allowable stress design
philosophy and low (relatively to current) values of the so-called “seismic coefficient,” to
calculate the horizontal seismic forces. Furthermore, detailing provisions were poor and, as a
result the spacing of hoops in columns was not adequate and there were no provisions for
detailing the beam-column joints. Examples of damage in these elements are shown on Figs.
11.5.11 and 11.5.12 (now demolished) from buildings in Chavriata and Lixouri. The building
of Fig. 11.5.10 (38o11'00.67''N, 20o22'54.93''E), 45 m from CHV1 in Chavriata (Fig. 11.5.8a)
was constructed in 2 phases: the 1st story was built in 1978 and the 2nd story in 2002. It suffered
no structural or infill wall damage in either earthquake despite its proximity to CHV1. Only
nonstructural damage was observed in a small kitchen on the 2nd floor (broken glassware, etc.).
Figure 11.5.10. Two-story reinforced concrete frame building next to the old school in Chavriata, 45 m from the CHV1 station (38o11'0.67''N, 20o22'54.93''E) that experienced no structural damage.
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Figure 11.5.11. Three-story building in Lixouri (with partial 4-story extensions) probably constructed before 1984 following the 1959 code (38o12'14.17''N, 20o26'01.45''E). Collapse of some infill walls on 3rd and 4th floors (incomplete, no door/window frames) and cracks at column-beam joints on 4th floor.
Figure 11.5.12. Three-story building in Lixouri (Aravantinou Krasopatera St., 38o11'36.81''N, 20o26'11.42''E), probably built before 1984. The two upper floors did not appear to suffer any structural or infill wall damage. The columns and shear walls (or wide columns) of the 1st floor were severely damaged (soft-story failure). The structure was later demolished.
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Built between 1984-1995 (1959 seismic code, with 1984 supplementary provisions)
The 1984 additional provisions to the 1959 seismic code included capacity design of
columns in bending and specific detailing to guarantee local ductility. Structures complying
with the 1984 supplement to the 1959 code provisions behaved satisfactorily.
For example, Fig. 11.5.13 shows observations at the three-story Palatino Hotel in Argostoli
(38o10'80.00''N, 20o29'14.40''E). The three-story building has one basement level and it
consists of two parts with dimensions 23m × 12m and 23m × 14m, separated by a thermal
expansion joint that opened during the earthquakes (Fig. 11.5.9b). The building had some
nonstructural damage in contents and infill walls.
Figure 11.5.13. (a) Three-story hotel building in Argostoli (38o10'80.00''N, 20o29'14.40''E) designed in 1989 using the supplementary provisions to the 1959 building code; (b) width of the construction join opening; (c) broadening of joint after the 2nd event.
The two-story building of Fig. 11.5.14 is located in Aghios Dimitrios (38o14'36.51''N,
20o25'41.91''E). It has a reinforced concrete frame structure designed to accommodate three
stories, although only two of them are built. The ground floor does not have infill walls (soft
story). Reconnaissance teams observed soft story failure with disintegration of concrete and
fracture of the closely spaced, single rectangular hoops of the columns. The further away
columns were from the stair, the greater the building rotation and the column damage.
(a) (b) (c)
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Figure 11.5.14. Two-story RC frame with infills in 2nd story in Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E). The building plan is rectangular with one side twice as long as the other.
Built from 1995 to present (current Greek code EAK-2000)
Given that Cephalonia is in the highest of the three seismic zones in Greece, the current
seismic code EAK-2000 does not allow soft stories (open ground floors). The vast majority of
structures built using the current code behaved well with practically no damage at all (including
no damage to infill walls). Figure 11.5.15 shows typical examples of these newer buildings in
Lixouri.
Figure 11.5.16 shows a two-story RC framed structure with shear walls in both directions
and clay-brick infill walls in Livadi (38o15'24.81''N, 20o25'31.77''E). It was completed in 2004
and no structural damage was observed in any of the RC frame elements. However, extensive
infill wall cracking and failure was observed as shown in the photos of the interior and exterior.
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Figure 11.5.15. Typical buildings in the city of Lixouri designed according to the current seismic code EAK-2000 had no visible damage.
Figure 11.5.16. Two-story house in Livadi (38o15'24.81''N, 20o25'31.77''E), east of the Lixouri-Argostoli road. (a) infill wall cracking from the exterior; (b) infill wall failures from the interior.
(a)
(b)
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11.6 Special Cases of Structural Interest MUTLIPLE ADDITIONS WITH MULTIPLE CODES
The Greek society of Cephalonia has a family structure where several generations live
together under one building. To accommodate this, the original building (usually of Arogi type
described in the previous section) typically has had horizontal and vertical additions at different
time periods and under different seismic codes. As a result, unique case studies of structural
interest were identified of mixed construction methods using different seismic codes in the
same building. Three of those cases are documented in this Section, discussing two-story
buildings consisting of the original structure and additions (Figs. 11.6.1 to 11.6.3).
Case 1: The Livadi building of Fig. 11.6.1 (38o15'26.13''N, 20o25'21.38''E) suffered
damage on the upper floor, but no visible exterior damage to the lower floor. It is a RC frame
structure with clay brick walls constructed in the 1980’s. The north part of the 1st floor was an
Arogi house built in 1953. In 1973, both a lateral addition and a 2nd floor were constructed.
The Arogi house was fully enclosed within the 1st floor of the addition. As shown on Fig.
11.6.1, all upper floor columns developed plastic hinges at their top, where they connect to the
beams. The smooth steel reinforcement bars were rusted where exposed. Transverse column
reinforcement were spaced at 25-30 cm and did not continue through the joint.
Figure 11.6.1. Two-story house in Livadi (38o15'26.13''N, 20o25'21.38''E). Damage is evident in every column of the 2nd floor and in some infill panels. No damage to the 1st floor was visible from the exterior.
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Case 2: Figure 11.6.2 shows photos and a sketch of the plan and side views of a building
in Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E) which was constructed in three phases.
The 1st phase was an Arogi house built in 1954, the 2nd phase was a lateral addition completed
in 1981, and the 3rd phase was a 2nd floor addition built in 1990. This structure suffered no
structural damage. It appears that the building was founded on backfill soil supported by a 1-
m tall cinder-block retaining wall (black line on Fig. 11.6.2). The retaining wall failed and the
whole structure displaced 1-2 cm towards the dashed line. Due to the fact that the L-shaped
(green color) columns on the south side of the structure were founded on isolated spread
footings, the columns were separated from the old Arogi house columns by approximately 1
cm at the bottom as shown on the lower left part of the figure.
Case 3: The two-story building of Fig. 11.6.3 in Aghios Dimitrios (38o13'50.45''N,
20o25'49.78''E) was constructed in two phases and partially collapsed during the earthquake
events. The 1st story is an Arogi type construction (concrete frame encasing cinder block walls)
and the 2nd story (vertical addition with columns that extended from the 1st story into the 2nd)
is a RC frame with clay brick infills built in 1978. The structure was damaged but remained
standing after the 1st event showing moderate shear cracking in the walls and in some of the
columns, prompting the owner and his professional engineer to use some shoring to support
the building in case a 2nd earthquake occurred. The column longitudinal reinforcement
consisted of four bars with stirrups approximately at every 50 cm. After the 2nd event, large
shear cracks occurred in the columns as well as the walls of the 1st story resulting in the
significant tilting of the 2nd floor.
It can be assumed that if the 2nd story addition had not been constructed, the single-story
Arogi structure with its encased reinforced cinder block wall to the RC frame could have
resisted the seismic loads from the two seismic events, although its members were lightly
reinforced. This hypothesis can be further supported by the observed good response of Arogi
houses throughout the Paliki peninsula area, as demonstrated by the three single-story Arogi
houses within 50 m from the CHV1 accelerometers that survived the earthquakes with minimal
damage, discussed in the previous section (see Fig. 11.5.7). When the 2nd story was added
(without any additional strengthening of the members in the 1st floor) the seismic load doubled.
This caused moderate shear cracking in the walls and columns of the first story during the 1st
event. When the 2nd earthquake event occurred, the already weakened first story failed.
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Figure 11.6.2. Top: sketch of the building plan view in Aghios Dimitrios (38o14'36.51''N, 20o25'41.91''E) and pictures showing the structure and its connection to the foundation. Bottom: sketch of the building elevation. Colors indicate the three phases of the construction.
1990 addition
Built1954
1981 addition
Built1954
1981 addition
1.0 m tall cinder block retaining wall
partially failed
NS
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Figure 11.6.3. Tilted 2-story building in Aghios Dimitrios (Arogi house on 1st floor and 1978 RC clay-brick infill frame on 2nd floor). Failed columns and walls of the 1st story showed few stirrups along the columns and only 4 longitudinal reinforcing bars in the cross section (38o13'50.45''N, 20o25'49.78''E).
Overall, structures built in two or three phases behaved well. The buildings that
experienced damage were constructed before 1984 (under the seismic code of 1959) with
limited transverse reinforcement in the columns and no transverse reinforcement in the joints.
PUBLIC LOW INCOME HOUSING COMPLEX
A public low income housing complex was one of the most heavily damaged buildings in
Lixouri (38o25'81.19''N, 20o26'01.84''E). The complex is a series of two- and three-story
structures built during the 1960’s under the first 1959 seismic code. The structures suffered
extensive, non-repairable flexural and shear damage in most vertical RC structural members
(Fig. 11.6.4, top). A number of buildings, primarily those strengthened in the vault with fiber-
reinforced polymers, had moderate or minor damage and were classified as repairable.
In contrast to the behavior of the public housing complex, all of the newer buildings in the
immediate vicinity remained essentially intact as they were built after 2000, in accordance with
Longitudinal Reinforcement
Stirrup
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the current seismic code. In many cases, the new buildings had code-imposed design
differences that likely contributed beneficially to their good behavior, e.g. mat foundation
rather than spread footings, or RC walls on the ground floor rather than brick masonry infills.
Figure 11.6.4. Public low income housing complex. Top: severe damage of the three story buildings built in 1962. Top right: lack of shear reinforcement. Center: public housing blocks/units. Buildings with red roof on the lower portion are undamaged two-story houses built after 2000 with the current seismic code. Bottom: Repairable damage at two-story buildings built in 1978.
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TYPICAL DESIGN DRAWINGS AND DOCUMENTATION
In Greece, the building owners usually have a copy of the design drawings and construction
permit. Our reconnaissance teams have obtained copies of these documents for approximately
a dozen of buildings, several of which are in the immediate vicinity of recording stations and
behaved satisfactorily (Fig. 11.6.5, 38o11'0.67''N, 20o22'54.93''E). The documents, combined
with photographs and recorded motions can be used to further study the behavior of the
buildings.
Figure 11.6.5. Typical drawings collected for the 2-story RC building shown on Fig. 11.5.7, about 50 m from CHV1 accelerometer in Chavriata (38o11'00.67''N, 20o22'54.93''E). Construction was done in two phases, in 1978 with an addition in 2000. The building suffered no visual structural damage.
Future versions of the report will provide organized information on the collected structural
documentation, which is currently underway.
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BULDING INSTRUMENTATION
Following the 1st event, the EPPO-ITSAK team installed a mobile accelerometer
instrumentation array in a two-story (with one basement) building in Lixouri to record potential
aftershocks. The building selected is the new administrative building of the Lixouri hospital
(Fig. 11.6.6) that was erected in 2009, designed with the latest Greek seismic code in
combination with the Eurocode EC-8 provisions. The construction was made possible with a
grant from the Stavros Niarchos Foundation (snf.org). The record of station ARG2 in Argostoli
showed a PGA = 0.38 g and had similar spectral shape as the design response spectrum, as
discussed in Section 11.5 and shown on Fig. 11.5.2. The building behaved very well in the 1st
event, with essentially no damage to either its load bearing structural system or the infill walls.
The particular structure was selected for instrumentation because: (i) it has a more or less
“regular” structural and architectural system, both in plane and height (i.e., no soft story, static
eccentricities or other factors that would lead to particularities in its seismic response); (ii) its
plan dimensions and height (two stories) are representative of Cephalonia buildings; (iii) it is
stand-alone, with no adjacent buildings that could affect its response (e.g., through pounding);
(iv) it is a public building, with easier accessibility than private structures; (d) it does not have
a high occupancy that could accidentally disrupt the operation of the instrumentation system.
The ground floor was not instrumented as it was temporarily used as an emergency medical
center, since the nearby main hospital (“Mantzavinateio”, discussed in Section 11.7) building
was evacuated until its seismic safety was evaluated by professional engineers; (vi) as-built
drawings were available that can facilitate numerical modeling that will be further calibrated
using the recorded response of the building in the aftershocks and the 2nd event.
Fig. 11.6.6. The administration Lixouri building (left) and photos of instrumentation with special accelerometer array (right).
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The special structural array used in the instrumentation consists of a central recording unit
(type K2© by Kinemetrics Inc.), that can support up to 12 sensors (uniaxial, ± 2g full scale,
Episensor© accelerometers). The recording unit has a 19-bit resolution, a sampling rate
capacity of up to 200 sps and a dynamic range of 108 dB @ 200 sps. The system can
accommodate setting independent triggering threshold for each sensor (from 0.01% to 100%
full scale), while the user can predetermine the sensors, or combinations of them, that will
trigger the system. Recordings are stored in the system’s flash memory, and can be retrieved
either in situ or through a modem.
Figure 11.6.7. Instrumentation layout of Administration building at Lixouri.
The instrumentation, shown on Fig. 11.6.7, includes 9 uniaxial sensors in sets of 3, at 3
building levels: basement, 1st floor (what would be called 2nd floor in the US) and terrace. As
previously described, the ground floor level (or 1st floor in the US) was not instrumented. At
each level, 2 uniaxial sensors were placed in parallel along the floor’s edges (Fig. 11.6.7 in red
color), and the 3rd (Fig. 11.6.7 in blue) was placed in an orthogonal direction along one of the
other two edges. In this way it is possible to record the structural response in the two
translational orthogonal and torsional directions.
The recorded response of the building will be used to assess its dynamic characteristics
(eigenvalues, eigenmodes, and damping ratios) that will assist in properly calibrating finite
element models of the structure that will be used to further investigate the response to seismic
excitations, including the 1st event. This EPPO-ITSAK research effort aims at contributing in
the advancement of knowledge of seismic response of civil engineering structures (Karakostas
et al. 2003, 2005, 2006, Lekidis et al. 1999, 2005, 2013, Sous et al. 2004). The research effort
is ongoing and results will be presented in future versions of this report.
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11.7 Public Buildings INTRODUCTION
This section presents reconnaissance information for public buildings of Cephalonia,
including administrative, critical, and school structures. Overall, the structural performance of
the public buildings inspected was satisfactory given the intensity of the earthquake ground
motions. As a result, immediate occupancy and next day serviceability was possible for most
of these buildings, also attributed to acceptable behavior of nonstructural components, with the
exception of the International Airport Terminal that had to close for three weeks due to
nonstructural components damage. In some cases, including schools, conservative measures of
evacuation and detailed engineering assessment were carried, partially due to feelings of
population insecurity due to their (still vivid) experience of the devastating 1953 earthquakes.
ADMINISTRATIVE AND CRITICAL BUILDINGS
The public administrative and critical buildings that were visually inspected by the
reconnaissance teams are all of Reinforce Concrete (RC) summarized in Table 11.7.1.
Constructed after the destructive 1953 earthquakes, they generally behaved well and with few
exceptions, became operative one or two days after the events. Some observations are
discussed in this section.
Table 11.7.1. Public reinforced concrete buildings visually inspected during reconnaissance.
Year of Design Damage
Construction Code (visual observation)
1 Hospital “Mantzavinateio” Lixouri 2 1937 / 1952 N/A Minor
2 Hospital Argostoli 2 N/A N/A Negligible
3 Town Hall Lixouri 2 1968 1959 Minor
4 County Court Argostoli 2 1962 1959 Minor
5 County Court Lixouri 4 1979 1959 Negligible
6 Tax Office Argostoli 4 1994 1985 Negligible
7 Tax Office Lixouri 3 2000 1995 Negligible
8 Port Authority (main/auxiliary) Argostoli 2 1960 1959 Minor/Moderate
9 Public Realty Office Argostoli 4 1999 1995 Negligible
10 Naval Academy (administrative) Argostoli 3 1973 1959 Minor
11 Archaeological Museum Argostoli 2 1957 / 2000 N/A Moderate
12 Archaeological Museum Lixouri 2 N/A N/A Negligible
13 Prefectural Division of Ionian Islands Argostoli 3 1957 RC1954 Minor
14 Airport Terminal Argostoli 2 N/A N/A Minor
15 Police Station Argostoli 3 >2000 2000 None
Structural Type
Reinforced Concrete
(RC)
ID BuildingNo. of Stories
Location
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The Cephalonia International Airport terminal building (ID #14, coordinates 38°7'10.0''N,
20°30'17.7''E) suffered nonstructural damage, described in detail in Section 11.9. The interior
masonry walls cracked and parts of the roof cladding fell. The terminal remained closed to the
public for three weeks. (Fig. 11.7.1)
Figure 11.7.1. Cephalonia International Airport terminal building (ID #14, coordinates 38°7'10.0''N, 20°30'17.7''E): (a) aerial photo; (b) nonstructural damage after the 2014 events resulted in closing the terminal for three weeks.
The Lixouri City Hall (Fig. 11.7.2, ID# 3, coordinates 38°12'3.53"N, 20°26'14.92"E)
suffered damage following both events. Figure 11.7.2a shows the building before the
earthquakes and Figs. 11.7.2b,c show damaged columns and overturned statue after the 2nd
event. Further details on statues overturning is provided in Chapter 9 of this report.
Figure 11.7.2. Lixouri Town Hall. (ID#3 in Table 11.7.1; coordinates 38°12'3.53"N, 20°26'14.92"E). (a) before the 2014 events; and after the 2nd event: (b) column damage; (c) overturning of statue.
The main and auxiliary buildings of the Port Authority in Argostoli (ID #8, coordinates
38o10'44.8''N, 20o29'23.3''E) remained in operation despite extensive ground deformations in
(c)
(b)
(a)
(a) (b)
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the overall bay area. Settlements of 5 to 10 cm and tilting of 0.7o were measured. Construction
joints with adjacent buildings opened by up to 5 cm (Fig. 11.7.3).
Figure 11.7.3. Open construction joint at Argostoli Port Authority (ID#8 in Table 11.7.1; coordinates 38o10'44.8''N, 20o29'23.3''E).
The Merchant Naval Academy (Fig. 11.7.4, ID# 10) is located 700 m north of the
Argostoli's main square (coordinates 38°11'4"N, 20°29'9"E) and has been operating since
1975. It is considered one of the most prominent naval academies in the country. The complex
has two main blocks, each one of which consists of three buildings separated by joints (Fig.
11.7.4a). Minor diagonal cracks were observed mainly on a few external masonry walls and
extensive pre-existing corrosion was evident (Fig. 11.7.4b).
Figure 11.7.4. (a) Merchant Naval Academy building (ID#10 in Table 11.7.1) in Argostoli (coordinates 38°11'4"N, 20°29'9"E; photo from kefalonia.net.gr); (b) Observation following the 2nd event of lack of shear reinforcement and corrosion of rebars.
The Argostoli Archaeological Museum (Fig. 11.7.5, ID# 11, coordinates 38°10′40″N
20°29′17″E) was constructed in 1957 to replace the original one which was destroyed during
the 1953 earthquakes that resulted in loss of several findings from the first Marinatos
archaeological excavations. The Ministry of Culture conducted a rehabilitation and repair
(a) (b)
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project from 1998 to 2000. The reconnaissance teams observed concrete spalling due to
reinforcement corrosion at the base of the columns. A number of exhibits overturned or fell
within their showcases.
Figure 11.7.5. Argostoli Archeological Museum (ID#11 in Table 11.7.1; coordinates 38°10′40″N 20°29′17″E). (a) photo taken after the 2000 rehabilitation but before the 2014 events (mygreece.travel); (b) concrete spalling; and (c) minor cracking at short columns. Both photos taken after 2nd event.
The main General Hospital of Lixouri “Mantzavinateio” (ID #1 in Table 11.7.1,
coordinates 38o10'44.8''N, 20o29'23.3''E) is a 2-story RC building completed in 1957 with floor
plan area of 625 m2. Its construction began in 1937 but from 1937 to 1952 the construction
stopped with only the structural frame in place (Fig. 11.7.6a). A seismic retrofit program for
the hospital started in 2004 by collecting data, including performing geotechnical subsurface
and laboratory investigation and non-destructive testing on the foundation and superstructure
(Figs. 11.7.6b,c). The retrofit was completed in 2012. The hospital was evacuated preventively,
although no major damage was observed, following the 1st event and was back in operation on
February 6th, few days after the 2nd event (Fig. 11.7.6d, inkefalonia.gr, 2014) following
engineering assessment (Bardakis, 2014). Visual inspection of our reconnaissance teams after
the 2nd event did not reveal any significant damage to the structural load bearing system.
(a)
(c)(b)
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Figure 11.7.6. Lixouri “Mantzavinateio” General Hospital (ID #1, 38o10'44.8''N, 20o29'23.3''E): (a) historic photo of structural frame completion prior to 1953; (b,c) structural and geotechnical investigations for 2004-12 seismic retrofit; (d) evacuation after 1st event (inkefalonia.gr, 2014). Following assessment, the hospital was deemed safe and operations resumed few days after the 2nd event. Retrofit and historic information and photos a,b,c from Barthakis (2014).
Examples of public buildings with satisfactory structural responses include a three-story
building of the Prefecture (ID #13) constructed in 1957 which exhibited only a limited number
of hairline cracks in the infill walls and a two-story building of the Court House in the center
of Argostoli (ID #4, coordinates 38°10'37"N, 20°29'18"E), constructed in 1962 (Figure 11.7.7).
Figure 11.7.7. Examples of satisfactory behavior of Argostoli administrative public buildings: (a) Prefecture building (ID #13); and (b, c) Court House (ID #4, coordinates 38°10'37"N, 20°29'18"E).
(a)
(b) (c)
(a)
(b)
(d)
(c)
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SCHOOLS AND OTHER EDUCATIONAL BUILDINGS
Following assessment by the Organization of School Buildings (Ο.Σ.Κ.), 37 educational
units in Cephalonia were classified as “A” (immediate occupancy), 19 as “B” (immediate
occupancy with rehabilitation after school hours), and 9 will restore operation after the damage
is repaired. Table 11.7.2 shows a summary of the most important educational structures that
had some level of damage. For comparison purposes, we include the Technological
Educational Institute (T.E.I.) which accommodated the Argostoli crisis management center and
the GEER/EERI/ATC reconnaissance teams meetings, and remained intact after the two
seismic events. Damage at “Petritsio” High School of Lixouri (ID#1) is shown on Fig. 11.7.8.
Table 11.7.2: Educational buildings visually inspected during reconnaissance and assessed by Ο.Σ.Κ.
Figure 11.7.8. “Petritsio” high school, Lixouri (School ID#1, 38°12'12.87"N, 20°26'15.43"E): (a) prior to 2014; after 2nd event: (b) concrete spalling at external beam; (c) beam-column joint failure.
(c)(b)
(a)
Year of Design Damage
Construction Code (visual observation)
1 “Petritsio” High School ** Lixouri 1-2 RC, Masonry 1959 N/A Minor-Moderate
2 2nd and 3rd High School Argostoli 2-3 RC, Masonry 1954, 1959 N/A Minor-Moderate
3 1st Preliminary School Lixouri 1 RC, Precast1959, 1985,
19951959 Minor-Moderate
4 2nd Preliminary School Lixouri 2 RC 1959 1959 Minor-Moderate
5 2nd Preliminary School Argostoli 2 RC 1959 1959 Minor-Moderate
6 2nd Primary School ** Lixouri 2 RC 1985 1985 Minor-Moderate
7 4th Primary School ** Argostoli 1-3 RC 1959 1995 Minor-Moderate
8 Preliminary School Keramies 1 Masonry 1959 1959 Minor-Moderate
9 Technological Educational Institute Argostoli 1 Precast 1995 1995 None
** multiple buildings
Structural TypeID SchoolNo. of Stories
Location
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11.8 Churches INTRODUCTION
The Greek Orthodox Churches of Cephalonia are of the Basilica type, which consists of a
longitudinal single nave (Fig. 11.8.1) with windows at both sides. The nave is separated from
the chancel by the iconostasis, a timber screen covered with icons of the Eptanisian (Ionian
Islands) Baroque era (Fig. 11.8.2). The chancel is positioned at the liturgical east end in the
Greek Orthodox churches. Cemeteries are often located in the area surrounding the churches,
separated at various levels by stone masonry or reinforced concrete retaining walls. The
behavior of cemeteries is extensively covered in Chapter 9 of this report.
Figure 11.8.1. Façade of typical Greek Orthodox Basilica church.
The Cephalonia churches have two types of belfries, both of which were inspected at the
locations shown on Fig. 11.8.3: (i) freestanding towers (Fig. 11.8.4), and (ii) belfries
incorporated into walls (Fig. 11.8.5), either free standing or connected to the main building.
Figure 11.8.2. Typical church nave and iconostasis.
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Reconnaissance work in the churches was led by Prof. Harris Mouzakis of the National
Technical University of Athens (NTUA) who performed inspections shortly after the 1st and
2nd events. The NTUA team collaborated with reconnaisance teams from the Institute of
Engineering Seismology and Earthquake Engineering (EPPO-ITSAK), 35th Ephorate of
Prehistoric and Classical Antiquities (LEEPKA) and Aristotle University of Thessaloniki
(AUTH). A total of 49 churches were inspected, mostly concentrated on the western of the
Paliki peninsula, as shown on Fig. 11.8.3 with details on Table 11.8.1.
Figure 11.8.3. Church locations inspected during reconnaissance efforts (top) with details in the western part of the Paliki peninsula (bottom).
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CHURCH STRUCTURAL CATEGORIES The churches can be classified in 7 categories based on their Load Bearing (LB) system:
1. Stone masonry dated back to the 12th century. The oldest one is a two-leaf stone masonry with lime mortar. Those structures have been subjected to strong ground motions, including the destructive earthquakes that took place in 1867 and 1953.
2. Stone masonry with internal timber structure that supports the ceiling, built after the 1867 earthquake and which have experienced the 1953 earthquake.
3. Stone masonry built after the 1867 earthquake which have experienced the 1953 earthquake.
4. Stone masonry of Category 3 which was repaired and strengthened with cast in-situ Reinforced Concrete (RC) members (columns, beams and lintels).
5. Stone masonry of category 3 which was repaired and strengthened with internal RC wall in contact with the masonry wall.
6. Reinforced concrete frames with infill walls made of clay or cement units, built after 1953.
7. Fully reinforced concrete structures built after 1953, with concrete strength of 16 MPa (2.3 ksi) and smooth longitudinal and transverse reinforcing bars of 220 MPa (32 ksi) tensile strength.
Figure 11.8.4. Freestanding Tower belfry in Figure 11.8.5. Belfry incorporated into walls. Chavriata (38o10'57.47''N, 20o23'14.4''E).
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CHURCH RECONNAISANCE AND DAMAGE RATING SYSTEM
For the Unreinforced Masonry (URM) Churches (Categories 1 to 3 above), we used the
following notations to classify the Degree of Damage (DD):
DDURM0 No damage DDURM1 Slight damage (hairline cracks in a few walls) DDURM2 Moderate damage (fall of large pieces of plaster) DDURM3 Severe damage (large and extensive cracks in walls) DDURM4 Very severe damage (wall collapses) DDURM5 Collapse
For the Reinforced Concrete (RC) churches (Categories 4 to 7) the damage was classified
as:
DDRC0 No damage DDRC1 Negligible damage (hairline cracks in columns and beams of frame) DDRC2 Slight damage (shear cracks in non-structural walls) DDRC3 Moderate damage (shear cracks in columns and beams and in structural walls) DDRC4 Severe damage (spalling of concrete cover, buckling of reinforcing rods) DDRC5 Collapse (collapse of total or parts of building)
Figure 11.8.6. Collapse of masonry retaining wall at courtyard of The Virgin Mary church at Chavriata (ID#1 38o10'57.47''N, 20o23'14.4''E): (a) condition before the 2014 events; (b) damage after 1st event; (c) collapse after 2nd event.
(a) (b)
(c)
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Table 11.8.1. Cephalonia Orthodox Churches, including name, location, century of construction and repair, Category of Load Bearing (LB) system and Degree of Damage (DD) from the 2014 events.
Century of LBConstruction / Repair Category
1 The Virgin Mary Chavriata 17 /20 4 DDRC32 Apostles Havdata 19 2 DDURM33 Birth of Virgin Tipaldata 20 6 DDRC24 Aghios Ioannis Prodromos Favatata 19 / 20 5 DDRC35 Aghios Athanasios Favatata 20 6 DDRC36 The Virgin Mary Kechrionas 17 / 20 4 DDRC37 Aghia Paraskevi Monopolata 19 / 20 4 DDRC38 Aghios Constantinos Monopolata 19 2 DDURM49 The Virgin Mary of Rongoi Monopolata 17 1 DDURM310 Birth of Virgin Mary Kominata Kalata 18 1 DDURM411 Aghios Nikolaos Aghia Thekla 19 / 20 4 DDRC512 Aghia Thekla Aghia Thekla 17 / 20 2 - 4 DDRC313 Aghios Dimitrios Kalata 18 / 20 4 DDRC314 The Virgin Mary Skinea 19 / 20 4 DDRC315 Aghios Dimitrios Vlichata 20 7 DDRC316 Aghios Panteleimon Loukerata 20 6 DDRC217 Aghios Dionisios Livadi 20 6 DDRC218 Aghios Christoforos Farsa 20 6 DDRC219 Aghios Ioannis Kourouklata 20 6 DDRC120 Aghios Nikolaos Livathinata 20 6 DDRC221 Aghios Dimitrios Aghios Dimitrios 20 6 DDRC222 Aghia Paraskevi Atheras 19 / 20 4 DDRC323 Evangelistria Atheras 19 / 20 4 DDRC324 Aghios Ioannis Theologos Kontogenata 19 / 20 4 DDRC325 The Virgin Mary Kontogenata 18 / 20 4 DDRC326 Aghios Georgios Kontogenada 12 1 DDURM127 Aghios Vasilios Kontogenada 17 1 DDURM328 Aghia Erini Vovikes 20 6 DDRC029 Aghios Dimitrios Vovikes 20 6 DDRC230 The Virgin Mary Dematora 19 / 20 4 DDRC431 Aghios Vlasios (Blaise) Dematora 18 3 DDURM432 Aghios Nikolaos Rifi 19 / 20 4 DDRC233 Aghios Dionisios Damoulianata 20 6 DDRC234 The Virgin Mary Damoulianata 19 / 20 4 DDRC435 Prophet Elias Kaminarata 20 6 DDRC036 The Virgin Mary Parissata 19 / 20 4 DDRC337 The Virgin Mary Delaportata 20 6 DDRC338 Aghios Nikolaos Miniaton Lixouri 20 6 DDRC239 Aghios Spiridon Lixouri 20 6 DDRC240 Aghios Charalampos Lixouri 19 / 20 4 DDRC341 The Virgin Perligou Lixouri 20 6 DDRC242 Pantokrator Lixouri 20 6 DDRC243 Aghia Marina Soullari 17 1 DDURM444 Aghios Nikolaos Soullari 20 6 DDRC345 Aghios Spiridon Matzavinata 20 6 DDRC246 Aghios Dimitrios Soullari 19 / 20 4 DDRC247 Aghia Sophia Matzavinata 20 6 DDRC248 The Virgin Mary Matzavinata 20 6 DDRC349 Aghios Dimitrios Vouni 20 6 DDRC2
ID Name Location DD
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Table 11.8.1 summarizes the name, location, century of construction, and repair, type of
load bearing system and the observed degree of damage for the 49 churches visited during
reconnaissance. Note Aghios and Aghia stand for Saint, male and female, respectively.
Figure 11.8.7. Typical damage of stone gables in the churches of: (a, b) The Virgin Mary of Rongoi (ID#9) – (a) shows original condition prior to the 1953 earthquakes; (b) The Virgin Mary at Kechrionas (ID#6); and (c) Aghios Ioannis Theologos at Kontogenada (ID#24).
(a)
(b)
(c)
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Figure 11.8.8. Collapse of stone gable due to loss of continuity between stone wall and gable through installation of a RC lintel in the churches: (a) Aghios Nikolaos at Aghia Thekli (ID#11); (b) Aghios Vlasios (Blaise) at Dematora (ID#11).
Figure 11.8.9. Typical damage to Category 4 (strengthened masonry) churches to the top part of the walls due to inadequate overlap of the lintel reinforcment.
Figure 11.8.10. Typical damage in Category 5 churches: Collapse of the outer stone leaf of the west gable, at a church strengthened with internal RC wall.
(a) (b)
(a) (b)
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Figure 11.8.11. Typical damage to Category 4 churches at top part of the walls of a strengthened masonry church due to inadequate overlap of the lintel reinforcment.
Figure 11.8.12. Damage in Category 7 church: Permanent out of plane displacement of approximately 7 cm at the top of the walls along the long sides of the structure.
Figure 11.8.13. (a) Collapse of RC belfry top due to column failure (38o14'32.25''N, 20o28'26.40''E); (b) Detail of deformed rebars.
(a) (b)
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Figure 11.8.14. Category 1 Church of Aghia Marina at Soulari (ID#43): (a) before the earthquakes (b) Collapse of bell tower (c) Partial collapse of the east stone gamble.
Figure 11.8.15. Category 6 church experienced moderate damage of the RC frame infills. The roof tiles located at center of the building were displaced but the ones closer to the edges remained intact.
(a) (b)
(c)
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Figure 11.8.16. Severe nonstructural damage was observed in many churches: (a) fallen objects and out of plain deformation of iconostasis; (b) damage due to falling stones.
(a)
(b)
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SUMMARY OF CHURCH PERFORMANCE
Unlike the residential and public buildings which, in their majority, suffered minor to
moderate damage under the two strong earthquake events, the Cephalonia churches exhibited
extensive structural damage (even partial collapse), and severe nonstructural damage. This can
be attributed to their construction type, retrofit history, and lateral force resisting system of 7
main categories presented in this section. Most of the churches are very old, tracing back to the
17th century, and have accumulated structural strain from the several historic earthquakes in
the past, which must have played a significant role in their response to the 2014 event. For
example, in many cases in-plane masonry failure initially propagated within the wall following
the 1st event and caused out-of-plane structural damage or collapse after the 2nd event.
Church behavior related to the Load Bearing (LB) Category can be summarized as follows
for the total of 49 churches inspected by the reconnaissance teams:
Categories 1 to 3 (stone masonry) suffered significant damage, with five being severely damaged. In many cases the stone gables partially collapsed (Fig 11.8.7 and 11.8.14).
Category 4 churches with Reinforced Concrete (RC) members added after the 1953 earthquake, performed better than Categories 1 to 3 with slight or moderate damage. In cases where a RC lintel was constructed between the stone wall and the gamble, loss of continuity appeared (Fig. 11.8.9). Damage of RC members due to insufficient reinforcement overlap extended to the nearby masonry walls (Fig. 11.8.11).
Category 5 churches typically experienced collapse of the outer masonry leaf as they disconnected from the inner one which remained attached to the RC wall (Fig.11.8.10).
Category 6 churches suffered slight damage with shear cracks in the nonstructural walls.
Category 7 churches typically experienced out of plane permanent displacement of the wall top along the long sides of the structure (Fig. 11.8.12).
Other general observations of damage include: (i) partial failure or collapse of retaining
walls in the church perimeter (Fig. 11.8.6); (ii) complete or partial collapse of many belfries
(Figs 11.8.13 and 11.8.14); (iii) moderate roof damage with falling tiles (Fig. 11.8.15) and
severe nonstructural components damage (Fig. 11.8.16), which could have caused human
injuries or loss of life that fortunately did not take place due to the time the earthquakes hit.
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11.9 Nonstructural Components INTRODUCTION
Damage of nonstructural components was extensive in the Lixouri area and significant in
Argostoli. This section presents observations of damage to nonstructural components in
buildings that did not have significant damage. These observations were made during
reconnaissance efforts in the period from February 8 to 11, 2014, primarily by the practicing
engineers of Easy Facilities, GMS, MRCE. The impact of this damage was substantial in the
function and the economy of the island. Nonstructural damage caused business to stop
operating, including banks, restaurants, and stores, and shut down the only airport in the island
for more than 10 days. On the other hand, the local owners of businesses, knowing first hand
their exposure to seismic hazard, often had applied empirical, common sense measures that
worked well in protecting their safety and valuables.
NONSTRUCTURAL CATEGORIES AND PERFORMANCE
We have grouped the nonstructural components observed during reconnaissance in three
categories, as per the commonly used references of FEMA E-74 and ASCE7-05/10:
Architectural Building utility systems (Mechanical, Electrical, and Plumbing) Furniture and contents
Table 11.9.1 summarizes the observed damage per nonstructural component Category and
indicates the photo that corresponds with the observations. Detailed descriptions of the damage
and potential deficiencies that led to the damage follow.
During reconnaissance, both acceleration and displacement or driftsensitive
nonstructural components were inspected. Accelerationsensitive components include
suspended ceilings, lights, mechanical equipment, etc. Drift-sensitive components include
partitions, façades, etc. Bracing and anchorage to structural elements is important in the
behavior of the nonstructural elements. The presence, type, and general conditions of the
bracing or anchorage were documented by the reconnaissance teams. Specific observations
with possible explanations for selected nonstructural components in each category are
presented in the following paragraphs. Special types of nonstructural components such as the
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infrastructure network piping systems, and rigid objects such as statues and objects placed in
churches and on tombs in cemeteries have been addressed in Chapters 9 and 10 of this report.
Table 11.9.1. Nonstructural components damage observations and construction or design deficiencies by Category of components: architectural, building utilities, furniture and contents.
ARCHITECTURAL COMPONENTS
Stairways 11.9.2
Heavy railings 11.9.1
Freestanding frames Fences 11.9.3
Glazing Façade and overhead (typically safety glass) 11.9.4
Heavy, usually of bricks, full-height
Heavy, usually of bricks, half-height
Light, gypsum board
Recessed light fixtures 11.9.6
Short polls in public sidewalks 11.9.7
Acoustic lay-in tile or gypsum board 11.9.6
Bracing 11.9.8
Roofs Ceramic or plastic tiles 11.9.10, 11.9.11
Parapets 11.9.12
Chimneys
Adhered or anchored veneer 11.9.13
Tile veneers (usually adhered to shear walls)
Piping Gutter pipes 11.9.14, 11.9.15
Lifeline Infrastructure Potable and wastewater networks
Equipment HVAC 11.9.16, 11.9.17
Suspended Mechanical Space Bracing 11.9.6, 11.9.18
Electrical Power transformer 11.9.19
Electrical panels Distribution panels
Accessories Desktop computers, printers, etc. 11.9.20
Office furniture Bank teller desks 11.9.21
Heavy bank vaults 11.9.23, 11.9.24, 11.9.25
Monuments attached to cemeteries See Ch. 9
Sculptures 11.9.22
Bookcases 11.9.26
Computer racks
File cabinets 11.9.27, 11.9.29
Objects on shelves 11.9.30, 11.9.31
Office shelves
Restaurant rolling storage units 11.9.32
Unreinforced Masonry
Veneers
Building Utilities (MEP)
Furniture and Contents
Rigid Objects
Storage
Architectural
Egress Means - Stairs
Interior Partitions
Lighting
Suspended Ceilings
Category Type Component Figure
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The following architectural components and potential causes of damage are discussed and
illustrated in Figures 11.9.1 through 11.9.9: egress means (stairs); freestanding frames; glazing;
interior partitions; lighting; suspended ceilings; unreinforced masonry; and veneers.
Egress Means – Stairs: As the primary means of egress, the performance of stairwells is
critical following an earthquake. Observations of damage in stairways often involved lack of
rolling supports at either end to accommodate interstory drift. Failure of base anchorage
occurred in heavy railings, as shown in Figure 11.9.1.
Figure 11.9.1. Base anchorage failure at heavy stair railings in Lixouri.
Large, heavy contents along egress routes could potentially fall over or block pathways and
exits. Figure 11.9.2 shows a series of unbraced filing cabinets and storage units that could tip
over and restrict access to the adjacent stairwell (38°10’27.3”N, 20°29’26.4”E).
Figure 11.9.2. Heavy, unbraced storage units with the potential to block means of egress in the National Bank branch of Lixouri. (GPS coordinates: 38°10'27.3''N, 20°29'26.4''E).
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Freestanding fences experienced collapse from rotation due to lack of foundations or
reinforcement. Figure 11.9.3 shows observed damage to fences not anchored to the ground.
Figure 11.9.3. Freestanding fences without foundations or reinforcement were damaged. (GPS coordinates: (a) 38°11'0.8''N, 20°22'53.9''E, (b) 38°12'41.0''N, 20°26'1.4''E).
Glazing: Façade and overhead glazing, although typically made with safety glass, were not
designed for seismic drift. The observed lateral frame deformation was the likely cause of the
significant cracking in glazing, as shown on Figure 11.9.4. FEMA (E-74) guidelines for
nonstructural components provides recommendations for adding more space around the pane
of glass where it is mounted between stops or molding strips in order to accommodate greater
frame distortions without cracking the glass.
Figure 11.9.4. Glazing failure due to lack of proper design for lateral frame deformation.
(a) (b)
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Interior Partitions: Heavy half-height partitions lack lateral bracing to the structure above
and were not engineered as cantilevers to the base. Light gypsum board partitions were not
isolated from building deformations. Figure 11.9.5 shows a typical method for mitigating
damage to partitions by installing diagonal bracing (FEMA).
Figure 11.9.5. Mitigation method for bracing interior partitions as recommended (FEMA, E-74).
Lighting: Recessed light fixtures did not have positive support from hanging, or any special
safety devices for the attachment of lens covers. Figure 11.9.6 shows damage to recessed
lighting in the National Bank branch of Lixouri.
Figure 11.9.6. Lack of support for ceiling tiles and recessed light fixtures in the ground level of the National Bank branch of Lixouri. (GPS coordinates: 38°10'27.3''N, 20°29'26.4''E).
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Street lights along public sidewalks are poorly anchored to the pavement. The supporting
metal columns lacked sufficient strength to withstand the earthquake movements. Figure 11.9.7
shows damage to two lamp posts that experienced foundation failure and damage midway up
the column in the Lixouri and Argostoli port areas.
Figure 11.9.7. Poorly anchored sidewalk lighting columns in: (a) Lixouri port (Easy Facilities team members George Tsalakias and Angeliki Psychogiou in the photo) and (b) Argostoli (GPS coordinates: (a) 38°12'7.2''N, 20°26'18.2''E; (b) 38°12'1.0''N, 20°26'18.2''E).
Suspended Ceilings: There was no bracing of the suspension grid for acoustic lay-in tile or
gypsum board ceilings. Figure 11.9.6 shows panels that fell from the ceiling at the National
Bank branch of Lixouri (38°10''7.3''N, 20°29'26.4''E), similar to damage recorded at several
locations in the meioseismal area.
The bracing system of the mechanical space in the suspended ceiling of Eurobank branch
of Argostoli (38°10'29.4''N, 20°29'28.2''E) suffered damage following the 2nd event. The
structural system is a moment frame structure erected in 1996 and had visible damage to several
nonstructural components. In the second floor mechanical space, a 20 m strut buckled, as
shown on Figure 11.9.8 (38°10'29.4''N, 20°29'28.2''E). The strut on the other side of the ceiling
bent but did not buckle. Figure 11.9.9 illustrates a mitigation option recommended by FEMA
to install diagonal bracing for ceiling supports.
(a) (b)
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Figure 11.9.8. Ceiling brace buckling in the Eurobank branch of Argostoli: (a) horizontal strut and (b) vertical brace. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
Figure 11.9.9. Mitigation option to provide diagonal bracing for ceiling systems in FEMA E-74.
Roofs: Typical architecture of Cephalonia includes tiled roofs. The tiles are mostly heavy
ceramic, with few newer tiles made of plastic that simulate the same look as the ceramic. It
was observed in numerous cases inspected in the meioseismal area that tiles fell from the roof
during the earthquakes as shown on Figure 11.9.10 (GPS coordinates: (a) 38°13'46.2''N,
20°25'48.0''E; (b) 38°13'45.6''N, 20°25'48.7''E). In most cases, the tiled roof base was not
properly anchored to the underlying concrete structure. Figure 11.9.11 shows an extreme case
of complete collapse of a tiled roof. Additional evidence of tile damage is presented throughout
this Chapter.
(a) (b)
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Figure 11.9.10. Roof tiles damage (GPS coordinates: (a) 38°13'46.2''N, 20°25'48.0''E; (b) 38°13'45.6''N, 20°25'48.7''E).
Figure 11.9.11. Collapse of tiled roof. Photo by V. Plevris of ASPETE team.
(a)
(b)
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Significant damage to parapets due to lack of bracing and pounding with adjacent buildings
during the earthquake events was observed in Lixouri as shown on Figure 11.9.12. Chimneys
also typically did not have proper bracing or anchorage to withstand the shaking caused by the
earthquakes.
Figure 11.9.12. Typical parapet gable frame failures in Lixouri.
Veneers: Adhered or anchored veneers experienced damage due to the pounding with
adjacent buildings. Figure 11.9.13 shows a marble veneer that was damaged from interaction
with the adjacent structure. Deformation of backing substrate was observed in tile veneers,
usually adhered to shear walls.
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Figure 11.9.13. Architectural marble veneer damage due to building pounding.
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BUILDING UTILITY SYSTEMS
Observations were made in MEP (Mechanical Electrical Plumbing) building utility
systems, namely piping; lifeline infrastructure; equipment; and electrical panels. Detailed
observations on lifeline infrastructure of potable and wastewater networks are presented in
Chapter 10. Characteristic damage in the remaining systems is illustrated in Figures 11.9.14
through 11.9.20 and discussed below.
Piping: Shown in Figure 11.9.14, gutter pipes separated from the external walls and
cracked surrounding supports likely due to inadequate anchorage. At the Lixouri Branch of
Piraeus Bank shown in Figure 11.9.14a, it appears that the ground settled and the structure
(supported by a grid of 20 steel piles) remained in place, causing the separation in the piping.
The reconnaissance teams noted absence of flexible joints that would allow for movement of
the pipes independent of the structure and mitigate the damage potential.
Figure 11.9.14. Improperly anchored gutter pipes with rigid connections. (GPS coordinates: (a) 38°12'7.2''N, 20°26'19.8''E; (b) 38°11'0.1''N, 20°22'55.9''E).
At a 2-story Reinforced Concrete (R/C) building located near the shore south of Lixouri
(38°11'36.08''N, 20°26'19.90''E), free-field soil settlement was observed in addition to the
collapse of its chimneys and roof tiles. Figure 11.9.15 shows a drainage pipe that was dislocated
from its collective pool as a result of surrounding ground settlement.
(a) (b)
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Figure 11.9.15. Dislocated drain pipe at the perimeter of a 2-story R/C building located near the shore south of Lixouri. (GPS coordinates: 38°11'36.08''N, 20°26'19.90''E).
Equipment: Heating, ventilating, and air conditioning (HVAC) equipment was typically
not properly braced or anchored. Large air conditioning (AC) units are typically placed on
building roofs. When poorly supported by simply sitting on bricks, the AC units displaced or
fell over, as shown on Figure 11.9.16 (38°10'27.0''N, 20°29'26.5''E). Figure 11.9.17 shows
appropriate bracing and bolting to the exterior wall of HVAC units in Argostoli that suffered
no damage. Distribution panels did not have proper anchorage and were often damaged due to
failure of the supporting partition walls.
Figure 11.9.16. Rooftop AC unit that fell off brick supports. (GPS coordinates: 38°10'27.0''N, 20°29'26.5''E).
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Figure 11.9.17. Mechanical external AC equipment with adequate bracing that suffered no damage in Argostoli.
Suspended Mechanical Space: Both horizontal and vertical bracing elements buckled in
few areas of the second floor mechanical space at the Eurobank branch of Argostoli, as shown
in Figure 11.9.8 (38°10'29.4''N, 20°29'28.2''E). Figure 11.9.18 shows cable trays in the same
mechanical space that were well braced and did not experience damage.
Figure 11.9.18. Well-braced cable trays in second floor mechanical space in the Eurobank branch of Argostoli. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
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Transformers: A power transformer pillar in Lixouri (38°11'55.63"N, 20°26'20.56"E)
suffered differential settlement (Fig. 11.9.19). One of the support columns appeared to have
punched in the ground for 1.7 cm, while the other one remained in place. This behavior could
partially be attributed to Soil-Structure Interaction (SSI) effects, as discussed in Chapter 8.
Figure 11.9.19. Differential settlement in power transformer pillar (GPS coordinates: 38°11'55.63''N, 20°26'20.56''E). See also SSI Section of Chapter 8.
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FURNITURE AND CONTENTS
Desktop computers, printers, and other accessories were not anchored or tethered. Figure
11.9.20 (38°12'8.4''N, 20°26'17.4''E) shows how many of these items were displaced or fell
onto one another.
Figure 11.9.20. Desktop computers and accessories without anchorage or support. Team member Ramon Gilsanz of GMS in the photo (GPS coordinates: 38°12'8.4''N, 20°26'17.4''E).
Heavy office furniture experienced rotational movement due to lack of floor connections.
The displacement of a bank teller desk is calculated on Figure 11.9.22 and shows the
dimensions of the unit and the direction of movement in relation to its original position.
Figure 11.9.21. Rotational movement of a heavy bank teller desk with no anchorage (GPS coordinates: 38°12'6.6''N, 20°26'17.4''N).
Plan Dimensions: 3.3 m x 1.1 m α = 312.4 cm ; b = 14 cm c = 20 cm ; d = 25.cm
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Several cases of rigid body motion (i.e., displacement and/or rotation) were observed in
marble statues and other large rigid objects, as detailed in Chapter 9 of this report. For example,
two marble statues standing opposite to each other at the entrance of Lixouri City Hall were of
particular interest (Fig. 11.9.22, 38°12'3.53"N, 20°26'14.92"E). Following the 1st event, the
statue located north of the building entrance (Fig. 11.9.22b) displaced and slightly rotated
towards the North without collapsing, since it was supported by the wall behind it. The trace
of the original base location is visible, indicating an almost uniaxial displacement of about 40
cm. The top portion of the statue eventually toppled after the 2nd event towards the SE direction
(Fig. 11.9.22). A similar response was recorded for the opposite standing statue at the south of
the building entrance, which also overturned in the same (SE) direction (Fig. 11.9.22a).
Figure 11.9.22. Overturned statues at the entrance of Lixouri City Hall. (GPS coordinates: 38°12'3.53''N, 20°26'14.92''E).
Rigid body motion was observed at several heavy bank vaults that did not have floor
connections or supports. Figure 11.9.23 contains an illustration of how the vault moved as a
rigid block at the National Bank (38°12.139'N, 20°20.318'E). Similarly, Figure 11.9.24 shows
measured vault rotational displacement, evident from the original marks on the floor prior to
the unit moving due to the earthquakes.
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Figure 11.9.23. Sliding and rotation of aheavy bank vault with no anchorage on the floor or ceiling. (GPS coordinates: 38°12'7.8''N, 20°26'19.2''E).
Figure 11.9.24. Rotational movement of heavy bank vault at the Eurobank branch of Argostoli. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
~ 5 cm
21.5 cm
51 cm
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A row of heavy vaults at the Eurobank branch of Argostoli (38°10'29.4''N, 20°29'28.2''E)
were not anchored or braced to one another and experienced rotational displacements of
approximately 2.5 cm. The dimensions recorded for one of the vaults are given in Figure
11.9.25.
Figure 11.9.25. Measurements taken (by Dimitri Kopanos of Easy Facilities team) at a row of heavy vaults at the Eurobank branch of Argostoli show approximately 2.5 cm of displacement. (GPS coordinates: 38°10'29.4''N, 20°29'28.2''E).
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Bookcases were overturned in many locations due to lack of support or connections to
adjacent walls. At the National Bank (38°12.139’N, 20°20.318’E), bookcases were laterally
braced to one another at the top and did not fall over. Contents fell off the shelves, but as
shown in Figure 11.9.26, the units were still standing.
Figure 11.9.26. Bookcases braced to one another for support but lacked shelving restraints. (GPS coordinates: 38°10’27.3”N, 20°29’26.4”E).
Computer racks were typically unanchored and unbraced. File cabinets had notable
rotational displacements due to lack of floor or wall supports. Figure 11.9.27 shows
measurements for a large file cabinet that rotated as a rigid block at the National Bank branch
of Lixouri (38°12'7.8''N, 20°26'19.8''E). This cabinet was against the wall parallel to the
shoreline, as shown from the exterior in Fig. 11.9.28. Many cabinet doors and drawers did not
have latches to prevent them from opening with their contents spilling during the earthquakes.
Collected data for this structure relating to rigid blocks is also presented in Chapter 9 of this
report.
Following the 1st event on January 26th, the National Bank branch of Lixouri (38°12'7.2''N,
20°26'19.8''E) installed corner hooks to the back of large cabinets for wall support. As shown
in Figure 11.9.29, this simple non-engineered solution prevented significant damage during the
2nd earthquake event of February 3rd.
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Figure 11.9.27. File cabinet with no anchorage (GPS coordinates: 38°12'7.8''N, 20°26'19.2''E).
Figure 11.9.28. National Bank branch of Lixouri located in the front row of buildings parallel to the shoreline (GPS coordinates: 38°12'7.8''N, 20°26'19.8''E). See also Chapter 9 for this case study.
~ 15 cm
~ 2.5 cm
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Figure 11.9.29. Corner hooks installed after the 1st event at top of large storage units and bookcases at the National Bank branch of Lixouri prevented movements in the 2nd event. (GPS coordinates: 38°12'7.2''N, 20°26'19.8''E).
Objects on shelves fell and broke in many instances because items were not secured
properly. Common sense solutions by the owners were adequate for most of these cases to
prevent significant damage in restaurants and stores. Figures 11.9.30 and 11.9.31 show such
examples in the areas that experienced the high levels of accelerations in Havdata village and
Lixouri port, respectively.
Figure 11.9.30. Simple rod restraints installed by a restaurant owner (shown here with team members) at Havdata village prevented toppling of bottles. (GPS coordinates: 38°12'14.3''N, 20°23'12.0''E).
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Figure 11.9.31. Shelving with simple string restraints at a gas station and supermarket in Lixouri.
Rolling storage racks in restaurants did not have seismic stoppers or brakes that may have
reduced damage during the earthquakes. Figure 11.9.32 shows overturned racks that displaced
contents and broke dishes and glassware.
Figure 11.9.32. Lack of seismic protection for rolling restaurant shelves and refrigerator units in Lixouri.
There is one (international) airport on the Cephalonia island that remained closed for
more than 10 days following the earthquakes mainly due to non-structural damage since no
significant structural damage was observed. Operations were limited with security checks done
manually in open spaces near the runways and public buses used as waiting areas. Figure
11.9.34 shows the interior conditions of the airport and Figure 11.9.35 shows the exterior of
the structure (38°7'10.0''N, 20°30'17.7''E).
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Figure 11.9.33. Cephalonia International Airport (38°7'10.0''N, 20°30'17.7''E).
CEPHALONIA AIRPORT
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Figure 11.9.34. Interior conditions of the airport. (GPS coordinates: 38°7'10.0''N, 20°30'17.7''E).
Figure 11.9.35. Exterior of the airport, no significant structural damage was recorded. (GPS coordinates: 38°7’10.0”N, 20°30’17.7”E)
(a)
(c) (d)
(b)
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CONCLUSIONS
Nonstructural components experienced extensive damage in the Lixouri area and also in
Argostoli. This damage made a significant impact on the operations and economy of the island.
Businesses could not operate, including banks, restaurants, and stores, and the only airport on
the island was shut down for more than 10 days. The damage shown in the photos could have
a greater effect on the economy of the island and future tourism.
In some cases, local business owners knew from personal experience that their risk and
exposure to seismic hazard was high, and applied empirical, common sense solutions that
successfully protected their safety and valuables. Falling objects could have caused significant
injuries and even loss of life, considering that the earthquakes occurred at times when public
areas were likely to be active and occupied. Specifically, the 1st event occurred at 5:55 pm on
a Sunday (January 26) followed by the 2nd event on February 3 at 5:08 am).
Most of the observed damage has been identified in the FEMA guidelines where suggested
measures are recommended. As the reconnaissance team members observed, and as is the case
in most countries, many of the nonstructural components were installed by non-engineers after
construction without consideration of earthquake hazard although the local code has seismic
provisions and prescribes calculations for expected deformations and loads depending on the
type, weight, and location (in floor height) of nonstructural components.
A common misperception is that building utilities and critical systems are heavy enough to
withstand earthquake shaking, but in reality these nonstructural components can cause
significant damage from pounding against adjacent objects or falling over, especially under
near-field pulse-like motions of high accelerations as in the Cephalonia events. It is critical to
increase public awareness of the risks and hazards of nonstructural systems in earthquakes.
The observed damage following the 2014 Cephalonia earthquakes highlights the
importance of seismic design of nonstructural components for life safety and post-earthquake
operations and the need to increase educational efforts in this direction. The detailed
reconnaissance information presented in this report for both acceleration- and displacement-
sensitive nonstructural components, together with several recorded strong ground motions in
the immediate vicinity of the collected information, presents an excellent opportunity to
enhance our knowledge on the behavior of nonstructural components and develop simple,
engineering and common-sense solutions to minimize their seismic risk exposure.
CHAPTER 12
Community Preparedness &
Response
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12 Community Preparedness and Response DAMAGE ASSESSMENT SURVEY
During the 2014 two main seismic events of January 26th (Mw 6.1) and February 3rd (Mw
6.0), some structural damage occurred, mostly during the 2nd earthquake. Damage assessment
survey efforts were led by the Greek Seismic Rehabilitation Agency (YAS) in two phases:
rapid (in 4,865 buildings) and detailed (in 2,770 buildings), mostly by teams of structural
engineers who work for public agencies, explained in detail in Chapter 11. According to the
Hellenic Earthquake Rehabilitation Services (HERS), the detailed assessment (shown in Fig.
12.1) tagged 46% of the buildings as safe (green), 48% as temporarily unsafe (yellow), and 6%
as unsafe (red). Of the 180 red buildings, 5% were made of reinforced concrete, 73% were
masonry, 17% were hybrid concrete-masonry, and 5% were other types, which indicated that
masonry buildings suffered the most. Geographically, 76% of the red and 60% of the yellow
buildings were in the Paliki peninsula area. By use and occupancy, 52% of the red buildings
were farm storage, warehouses, stables, etc., or had been abandoned, 39% were residential
buildings and 9% were commercial buildings such as offices.
Figure 12.1. Results of detailed assessment of 2,770 buildings (see Chapter 11 for details).
The underwater damage in ports was inspected by divers of the Greek military and divers
commissioned by the water network facilities management; evaluation also included video
camera inspections by the Athens Water Supply and Sewerage Company, EYDAP, which have
been presented in Section 8.2 and Chapter 10, respectively.
Detailed Assessment
Concrete Structure ‐ Safe
Concrete Structure ‐ Unsafe
Concrete Structure ‐ Repairable
Masonry Structure ‐ Safe
Masonry Structure ‐ Unsafe
Masonry Structure ‐ Repairable
Hybrid Structure ‐ Safe
Hybrid Structure ‐ Unsafe
Hybrid Structure ‐ Repairable
Other Structure ‐ Safe
Other Structure ‐ Unsafe
Other Structure ‐ Repairable
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GOVERNMENT RESPONSE AND FINANCIAL AID
The Greek Government responded quickly to the aftermath of the disaster declaring
Cephalonia a natural disaster zone. Shortly after the 1st event, government representatives -
including the prime minister- visited the island, and public safety agencies promptly performed
damage assessments and organized relief efforts, including assistance from the local Red
Cross. Additional temporary instrumentation of accelerometers and seismographs was
deployed to enhance the existing seismographic network (see Chapter 7), to record aftershocks
and future mainshocks that were considered likely given Cephalonia’s seismic history.
Despite the fact that there were no casualties and that the majority of the building stock
suffered little to no damage, the economic cost of the two events for the Greek government
was significant, in part because financial aid has been offered by the government to repair
buildings that were temporarily unsafe (yellow) or dangerous for use (red). More specifically,
eighty percent [80%] of the aid will be covered directly from the state, and the rest 20% will
be in the form of an interest-free loan to be paid back over a period of 15 years.
Specifically, for rebuilding structures of floor plan area up to 120 m2, (~ 1,200 ft2) the
government will provide: (i) €1,000/m2 (~ $1,400/m2) for residential buildings, (ii) €500/m2 (~
$70/ft2) for business and public facilities, and (iii) €250/m2 ($32/ft2) for farm storage structures,
warehouses, stables, etc. Churches will receive up to €800/m2 ($100/ft2) regardless of floor
plan area. For structural damage repair, the government will provide €450/m2 ($57/ft2) (up to
120 m2 area) for damage restoration of load-bearing and non load-bearing elements. For
nonstructural damage, the financial aid will be up to €250/m2 ($32/ft2). Funds will be provided
in successive instalments paid upon completion of specific stages of the work. For yellow or
red building owners, the government will subsidize rents to owners for a period of two years;
while for tenants, rent will be provided for up to six months.
Preliminary cost estimates of the financial aid plan described above bring the total cost of
replacing or repairing the damaged buildings up to €200 million ($275M), with additional costs
for rental allowances and reconstruction aid in the order of €16M ($22M) and €48M ($65M),
respectively. The Greek Government has appealed to European Union’s Solidarity Fund for
financial aid.
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EARTHQUAKE INSURANCE DATA
Earthquake insurance is not mandatory for residential or commercial structures, unless
specified by the bank issuing the mortgage. For critical facilities, insurance is required for a
fire event, but not for an earthquake. According to data from the Insurance Agencies Union
(Ένωση Ασφαλιστικών Εταιρειών) 17.5% of residential housing stock of Cephalonia had
earthquake insurance, mostly due to mortgage requirements. Approximately half of these were
under the National Insurance Agency (Εθνική Ασφαλιστική), the largest insurance company
in Greece (Foufopoulos, 2014).
Although Greece is located in one the most seismically active regions in the world, Greek
homeowners typically opt out of earthquake insurance, which is symptomatic of a poor
understanding of what earthquake insurance actually is, and what benefits it provides in the
occurrence of a catastrophic event. Since the market is very small, earthquake insurance is not
viewed as priority by the insurance companies. As a result, adding the earthquake risk factor
in a homeowner’s insurance does not increase the premium significantly. In simple terms, if
an insurance premium is on the order of 0.2% of the value of the structure, and there is a
deterministic hazard of a significant earthquake happening every 25 years, the total cost to the
owner for this insurance would be 0.2% x 25 = 5% of the value in these 25 years of life. The
repair costs for damage caused by one event may be smaller, damage however might be
detrimental to the structural integrity due to event sequences in areas like Cephalonia.
Insurance reimbursement is based on the earthquake magnitude. In general, insured houses
are reimbursed for damage caused by an earthquake of magnitude 6 or less. In the case of
multiple events, if damages are evaluated by inspection of the insurance company and the
house is deemed habitable, the insurance can adjust the premium and reimburse the owner for
damages caused by the next event in the same sequence. For the 2014 events, more than €6
million ($8.2M) will be distributed to the residents of Cephalonia, according to the Hellenic
Association of Insurance Companies (HAIC, 2014, ekathimerini.com).
COMMUNITY HOUSING AND SUPPORT
Following the two mainshocks and numerous aftershocks, some critical and essential
facilities were temporarily evacuated. In some cases, evacuation was enforced as a preventive
measure –given the earthquake history of the island-- which created discomfort to the residents.
Such examples include the Lixouri hospital, senior citizen housing and schools (see also
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Chapter 11), whose functions were moved to large cruise ships, public facilities or precast
temporary settings for several weeks (Figs. 12.2, 12.3).
Figure 12.2. Temporary housing options included a cruise ship (photo by reconnaissance teams).
Figure 12.3. Temporary housing options of tents (left AP, N. Stamenis, vcstar.com) or public facilities and churches for the elderly (right, from the web).
Temporary housing included tents offered by the army, two navy ships in Argostoli (550
beds) and the “Aegean Paradise” cruise boat in Lixouri with 600 beds (including free breakfast
and dinner offered by the ship owner for two months). Rainy weather made living conditions
hard, and several homeless people had to be moved to the ships. Many owners of houses
deemed as inadequate for use preferred to stay either with relatives or in their cars in order to
protect their houses from looting. Alternative housing options by the government included
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public buildings tagged as safe or precast temporary housing. Several local chapters of the
Greek Red Cross were immediately activated to help the communities and provide supplies, as
shown in Fig. 12.4 from the Patras Red Cross and Good Samaritan Volunteers and Lifeguards
(Σώμα Εθελοντών, Σαμαρειτών, Διασωστών και Ναυαγοσωστών).
Figure 12.4. Assistance by the Greek Red Cross immediately after the events. Photos from Patras volunteers of the Red Cross and Good Samaritans (Σώμα Εθελοντών, Σαμαρειτών, Διασωστών και Ναυαγοσωστών). Photos from patrasevents.gr.
Water supply was interrupted in Lixouri after the 2nd event, and bottled water was
distributed until the network was repaired (Fig. 12.5). Government authorities, churches and
volunteers also provided food and other aid to those whose homes were deemed unsafe.
Gracious financial support has been provided by various sources, including fundraising by
Greek communities -locally and abroad- (Fig. 12.6) and private donations from organizations
such as the athletic team Olympiacos, who offered €500,000 (about $700,000) towards school
recovery.
The people of Cephalonia generally handled the events stoically, as they have likely
experienced other earthquakes in their lifetime. This helped minimize panic and allowed for
emergency response to proceed smoothly. Psychological support was provided, especially to
children and families who had not experienced such a natural disaster before, including support
by the Children’s Psychology Clinic under their study for psychosocial needs due to seismic
events at “Aghia Sophia” Children’s Hospital in Athens.
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However experienced with the earthquake phenomenon and terminology, the public did
not seem to understand that nonstructural damage is expected after large seismic events for
code-compliant structures. The expectations by the residents were higher than the non-collapse
requirements of the seismic code, which was very effectively achieved under very strong
ground motions. The people complained about the impact of the earthquakes to their personal
and professional lives, which were mostly affected by nonstructural damage. This appears to
be the case in other earthquake-prone areas, and suggests that more effort is needed to educate
the public on their risk exposure and expectations of operations after large earthquakes.
Figure 12.5. Distribution of bottled water to Lixouri residents following the 2nd event (photo by reconnaissance teams).
Figure 12.6. Fundraising efforts in Athens and Sydney, Australia.
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Art has always been a big part of the Greek culture and a means of coping with strenuous
ordeals. Members of the Telethon for the Support of Cephalonia Committee filled the unique
bottle of Fig. 12.7 with water from the shore of Syros in the Aegean sea (at the east) to be
emptied from Lixouri in the Ionian sea (to the west). This gesture was inspired by the concept
that the two seas surrounding Greece are connected by the people who can face any difficulty
by being united and supporting each other in times of crisis. The bottle artwork was done by
archaeologist Maria Rota.
Figure 12.7. The bottle of water from the Aegean sea that was emptied at Lixouri in the Ionian sea to symbolize their connection and mutual support in the aftermath of the Cephalonia earthquakes of 2014. Artwork by archaeologist Maria Rota, photo from inkefalonia.gr.
CHAPTER 13
Conclusions and
Recommendations
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13 Conclusions Two major seismic events of moment magnitudes Mw = 6.1 and Mw = 6.0 struck the Greek
island of Cephalonia on January 26th and February 3rd, 2014, respectively, fortunately causing
no loss of life. The reconnaissance mission was unique for two reasons: First, it brought
together the local and highly qualified earthquake engineering community with US-based
GEER/EERI/ATC representatives, to form a multidisciplinary team of more than 60 people
that documented geotechnical, structural, and nonstructural observations. Secondly, the
reconnaissance approach was modified from the typical learning from failures to a new
methodology that includes a focus on learning from success and resiliency of the building
stock, natural geostructures, and communities, which responded well to some of the highest
ground motion levels ever recorded in Europe. Data collected, including instrumentation and
design documentation, can be used in combination with recorded ground motions and much-
needed in-situ testing to further understand and explain the good response of most structures.
MAIN OBSERVATIONS
Seismological and Recorded Motions
Both events occurred along the so-called Cephalonia Transform Fault, a well-documented
active offshore dextral strike-slip fault with a thrust component southwest of the island. Since
the seismographic network that recorded the events is installed exclusively east of the causative
fault, epicenters were only approximately located, while seismologists are still entertaining the
possibility of a pair of closely-spaced parallel causative faults that ruptured in sequence.
Satellite data from the second event revealed a maximum ground deformation of 12 cm
south-ward at the midpoint of the island’s west most peninsula (Paliki), and of 7 cm northward
along the east coast of the same peninsula. The highest horizontal Peak Ground Acceleration
(PGA) recorded during the 1st event was 0.57 g; the exceptionally high ground motion
amplitude and the characteristic shape of a near-field pulse of the record are consistent with
the station’s close proximity to the epicenter. The corresponding spectral acceleration (SA)
was 1.3 g for periods between 0.5 and 1.0 s. At the same station, the horizontal PGA reached
0.68 g during the 2nd event, with peak velocity of about 120 cm/s. The response spectra from
at least two recordings of the 2nd event far exceeded the current code design spectra for periods
that affect the 2- to 3-story structures of the island.
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Geotechnical Aspects
It is very likely that site effects played a key role in both events. The damage concentration
on sedimentary soils with poor mechanical properties, like the Lower Pleistocene sequence and
younger Holocene alluvial deposits in the Paliki peninsula, is indicative of significant soil
amplification. This observation supports the need for further studies including extensive site
characterization and site-specific response analyses. Given the pronounced irregular features
in the immediate vicinity of several ground motion recording stations, topography likely
affected the recorded ground motion.
Additional observations include liquefaction of Holocene coarse-grained sediments, rock
falls, and landslides. Widespread and repetitive liquefaction and lateral spreading were
documented, primarily at the Lixouri and Argostoli ports (two of the four main ports), within
less than 10 km from the epicenters. On the other hand, minimal –if any- damage was observed
at the ports of Sami and Poros, which are farther from the epicenters. Landslides and rock falls
were also concentrated on the western part of the island, closer to the epicenters, as were
retaining wall failures. As is typical, concrete walls were proven to be much more resilient
than unreinforced masonry walls.
Short-span reinforced concrete bridges, by far the most common type on the island,
performed well, with the exception of the Havdata bridge that suffered differential settlement
at both embankments. The historic (1830) multi-span stone Debosset bridge, which was
seismically retrofitted in 2005, showed no damage despite high accelerations recorded nearby.
Road embankments performed well, with very few instances of severe or moderate damage
that obstructed or delayed traffic. Landfills and dams also performed well without any damage.
Liquefaction manifested at the ground surface primarily as large horizontal and vertical
displacements of pavements on soft sedimentary sites and in areas with widespread
liquefaction, mostly in the town of Lixouri. Soil-structure interaction effects of differential
settlements and lateral deformation between pavements and structures were primarily
documented for pile-supported structures built on reclaimed land. Still, the relatively mild
structural damage in the reclaimed part of Lixouri could be partially attributed (from a soils
perspective) to the layer of unsaturated fill on top of the liquefied layers that acted as a
“protective cap.”
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Rigid Blocks
In stark contrast with the overall excellent performance of the building stock in the most
severely shaken region, very extensive damage was observed in almost all of the 18 cemeteries
of the Paliki peninsula and 9 additional cemeteries elsewhere on the island. The main cause of
tomb damage was toppling on the grave marble slab. Other failure patterns included slippage,
vertical separation, and/or rotation of blocks and tombstones without toppling. Controlling
factors were the block geometry and the characteristics of the seismic excitation. Since
cemeteries are often built on a hill, topographic amplification is a possible contributing factor
which needs further examination, along with directivity and local soil amplification.
Interestingly, rigid objects (crosses, vases, markings) located on tombs generally oriented in
the EW direction, consistently toppled towards the East. Other cemeteries, in the vicinity of
the damage observations exhibited different response or minor damage, even though general
geologic setting and altitude were similar. The toppling rate was surprisingly low in the vicinity
of the fault.
Extensive structural damage (even partial collapse), and severe nonstructural damage was
also documented for the 49 inspected Greek Orthodox Churches of Cephalonia. Similar to
other structures, severe damage was concentrated in the Paliki peninsula, near the epicenters.
The extent of damage was found to depend on the structure’s age, construction type, retrofit
history, and the type of lateral force resisting system.
Structural Aspects
Overall, the building stock of the island is relatively new. Most of the island was destroyed
by the strong earthquake events of 1953 and new structures were built using the 1st Greek
seismic code published in 1959 due to these earthquakes. There is a common practice of
building and expanding homes over the span of several generations. This building pattern is
largely due to the close-knit family social structure of Cephalonia. Several generations of a
single family typically live together in the same house, which they expand vertically and
laterally as their families grow. This results in buildings that have portions built decades apart
under different codes and structural systems.
The predominant building type is a mix of reinforced concrete, masonry infill, and wood
roofs. These structures typically range from one to four stories in height. The infill masonry
has concrete beams around openings that are dowelled to the concrete structure. This practice
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is different from confined masonry or regular infill masonry construction. Buildings of this
category were found among both residential and commercial structures. These low rise
reinforced concrete buildings behaved very well during the 2014 earthquakes, despite the fact
that they experienced spectral accelerations more than twice their elastic design values. Further
studies of these structures should be pursued, as they seem to be an economical cost for
structure is on the order of 20% of the total construction cost) design approach in high seismic
zones.
Infrastructure Lifelines
Lifelines -water and sewage systems- were being closely monitored and promptly repaired
by the national water company (EYDAP). Only the 2nd event caused a large number of leaks
in Lixouri. However most of the operational problems, like leaks and associated public health
risk incidences, emerged in the days following the 2nd event, as a result of network fatigue and
overflow of the sewage system.
Nonstructural components
Nonstructural component failures and installation deficiencies, like roof tile collapse,
inadequate bracing and anchorage to structural elements, lack of fence foundations, lack of
design to accommodate interstory drift, lack of seismic stoppers or brakes for rolling storage
racks, absence of flexible joints in piping, lack of floor or wall connections of heavy office
furniture, bookcases and bank vaults, not properly braced or anchored equipment, and
unsecured objects on shelves, were extensive in the densely populated towns of the island
(Lixouri and Argostoli). Their damage significantly affected the everyday function of the island
and its economy, and could have resulted in serious injuries or loss of life if the residents were
not intuitive about expecting the 2nd earthquake and for the good fortune of both major events
happening when businesses were not operating. The critical facilities of the Cephalonia
international airport Terminal remained closed for 3 weeks following the events and the
Hospital of Lixouri was evacuated, mainly due to nonstructural damage.
Community and Government Response
The Greek government responded with rapid assessment performed immediately following
the 1st and 2nd events. Some critical and essential facilities had to be evacuated temporarily and
some were evacuated as a precaution due to the known history of sequential earthquakes in the
island that created concerns to the residents. Examples of evacuated facilities include the
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Lixouri hospital and the schools, which were moved to large cruise ships for several weeks.
Although tents were made available by the army, the rainy weather made living hard and
several homeless people had to also be moved to ships or chose to sleep in their cars. Water
supply was interrupted in Lixouri after the 2nd event and bottled water was distributed until the
network became operable. Psychological help was provided, especially to children, who
experienced such a natural phenomenon for the first time. The people of Cephalonia handled
the events stoically, as they have most likely experienced earthquakes in their lifetime, which
helped to avoid panic and allow for emergency response to run smoothly. However, even these
experienced residents, appeared to not realize the success in achieving the life-safety goal of
the seismic codes by the very good structural behavior, but often complained about
nonstructural damage that caused impact to their business and life.
Economical
Despite the fact that the island suffered no casualties and the majority of the building stock
suffered little to no damage, the economic cost for the Greek government is significant. Rental
allowances for residents whose homes were deemed unsafe for immediate re-occupancy will
cost an estimated $22 million. An estimated additional amount in excess of $65 million will be
required for reconstruction aid. Preliminary cost estimates bring the total cost of replacing or
repairing the damaged buildings to more than $250 million. The Greek Government has
appealed to European Union’s Solidarity Fund for financial aid.
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LESSONS LEARNED AND FUTURE RESEARCH NEEDS
The GEER reconnaissance effort after the Cephalonia earthquakes has yielded a number of
invaluable datasets, lessons learned, and future research directions disproportionally larger
than the size of the affected area would have suggested. Thanks to the enthusiastic engagement
of the Greek research community and local authorities and residents, the experience gained not
only spans the areas of geotechnical, structural and lifeline engineering, but also extends
beyond the boundaries of technical knowledge into social studies (community emergency
response), public policy and public health. Above all, this event highlighted the advantages of
documenting and incorporating the lessons learned from past damaging events into updated
versions of seismic codes. The excellent performance of geotechnical and structural systems
gave us the opportunity to also learn from the success stories, to advance our understanding on
resilient infrastructure, hazard mitigation and risk reduction.
The immediate response and thorough reconnaissance by the GEER team in collaboration
with Greek researchers and the local authorities was invaluable and enabled collection of time-
sensitive data on structural and ground failures, such as soil ejecta in areas which suffered from
liquefaction, which could have been washed away by a rainfall before the teams arrived to the
sites. On the other hand, documented failures and shortcomings observed in the reconnaissance
efforts revealed lessons and needs for future research, including:
1. Expansion of seismographic network: the network is constrained on the eastern part of the
island, while most seismic events have originated on the western part. As a result, locating
epicenters is still underway as it has to incorporate a large margin of uncertainty. Additional
instrumentation in the western part would be desirable to record any future events.
2. Geophysical testing and high-resolution Digital Elevation Models (DEM): Site
amplification and topography effects have likely played a role in the damage distribution
and strong recorded ground motions. In-situ geophysical testing and topographic maps will
be necessary to quantitatively evaluate the relative contribution of each effect.
3. Detailed displacement measurements and site characterization of affected ports and
waterfront: The structural damage at Lixouri and Argostoli ports comprised primarily of
rotation and translation of quay walls at the waterfront, a typical damage mechanism for
waterfront structures on soft and/or liquefiable soils. However, no simple design
recommendation exist to limit the deformations of this particular type of structure in the
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event of strong seismic shaking. Improving our understanding on this topic would advance
our capabilities to predict and limit the number of failures in the future.
4. Seismic response of gravelly fills: Liquefaction ejecta in Lixouri and Argostoli ports
included numerous gravel particles. The fill materials at these locations, therefore, seem to
involve a significant amount of coarse grained (greater than #4 sieve) particles, which
makes their seismic response of particular interest.
5. Role of liquefied layers as natural base isolation of buildings: The minor structural damage
at Lixouri could be associated with beneficial effects of structures founded on a stiff non-
liquefied soil layer (cap) overlying liquefied soil layers that significantly filter accelerations
at the expense, however, of increased lateral displacement. Further understanding of this
effect in the context of performance based structural design, will require extensive site-
specific geotechnical investigation and site-specific numerical analyses.
6. Structural effects: This event provides a unique opportunity to enhance our understanding
of the nearly elastic response exhibited by the lateral load resistance mechanisms of
Reinforced Concrete buildings, which had been designed in accordance with the latest
Greek seismic code. Collected data in reconnaissance include detailed design calculation
and construction drawings, photos after each event, and records in the immediate vicinity
(within 50 m) of structures that behaved very well despite cases where recorded PGA
reached 0.8 g and spectral values where more than twice the elastic design values.
7. Near-field directivity effects: The vast number of rigid blocks that toppled in the inspected
cemeteries and the characteristically long period pulse recordings at Lixouri provides a
unique opportunity to study the near field effects on ground motions.
8. Nonstructural components: The collection of information, photos, measurements, and
security video footage can be used to enhance practices and simple solutions for protection
of nonstructural components. Education on FEMA and Eurocode guidelines for expected
deformations and loads depending on the type, weight, and location (in floor height) of
nonstructural components needs to be promoted.
9. Education and outreach: The intent of the seismic code on life-safety was achieved despite
the very high ground motions. However, the public did not seem to comprehend that
nonstructural damage is expected after large seismic events for code-complaint structures.
This appears to be the case in other earthquake-prone areas and further outreach is needed
to better educate the public on their risk exposure.
CHAPTER 14
References
GEER/EERI/ATC Cephalonia, Greece 2014
Report Version 1
14 References Al Atik, L. and Sitar, N., 2010. Seismic earth pressures on cantilever retaining structures, J.
Geotech. & Geoenvir. Engrg. 136(10), 1324-1333. Albini, P., Ambraseys, N.N. and Monachesi, G., 1994. Material for the investigation of the
seismicity of the Ionian Islands between 1704 and 1766, Materials of the CEC project: Review of Historical Seismicity in Europe, CNR, Milano, 2, pp. 11-26.
Al-Homoud A.S., Whitman, R.V., 1995. Comparison between the prediction and results from dynamic centrifuge tests on tilting gravity walls, Soil Dynamics & Earthquake Engineering 14, 259-268.
Amato, E. d', 1715. Lettere di eruditi della Chiesa. Genova. (in Italian). American Society of Civil Engineers (ASCE), 2005. ASCE/SEI-7-05 Minimum Design Loads
for Buildings and other Structures, Reston, VA. Anagnostopoulos S.A., Rinaldis, D., Lekidis, V.A., Margaris,V.N. & Theodulidis, N., 1987.
The Kalamata, Greece Earthquake of Sept. 13, 1986, Eq Spectra, 3(2), 365-402. Andrews, D.J., Hanks, T.C., and Whitney J.W., 2007. Physical limits on ground motion at
Yucca Mountain, Bull. Seism. Soc. Am. 97, 1771-1792. Applied Technology Council (ATC), 1996. Earthquake Aftershocks – Entering Damaged
Buildings, ATC TechBrief 2, Redwood City, CA. Applied Technology Council (ATC), 2005. Postearthquake Safety Evaluation of Buildings,
Field Manual ATC-20-1, 2nd Edition, Redwood City, CA. Applied Technology Council (ATC), 2002. Rapid Visual Screening of Buildings for Potential
Seismic Hazards: A Handbook, Report No. ATC-21/FEMA 154, 2nd Edition, Redwood City, CA.
Aravantinos, P. (Αραβαντινός, Π.), 1856. Χρονογραφία της Ηπείρου των τε όμορων Ελληνικών και Ιλλυρικών χωρών, Τόμος Α, Αθήνα, (in Greek).
Archives de la Guerre (AGP), 1628-1807. Archives Historiques, Paris, (in French). Archivio di Stato di Venezia (ASVe), 1693-1722. Cinque Savi alla Mercanzia, Lettere, Rettori,
Cefalonia, b. 561., (in Italian) Archivio di Stato di Venezia (ASVe), 1712-1764. Cinque Savi alla Mercanzia, Dispacci,
Consoli, Patrasso, b. 728, (in Italian). Archivio di Stato di Venezia (ASVe), 1728-1794. Cinque Savi alla Mercanzia, Dispacci,
Consoli, Arta, b. 632, (in Italian). Archivio di Stato di Venezia (ASVe), 1742a, b, c. Senato, Dispacci, Provveditori da Terra e da
Mar, Provveditori Generali da Mar, f. 987 (luglio 1740-aprile 1742): a) Supplica dei Sindici di Zante, Zante, 26 febbraio 1742; b) Lettera, Provveditore di Zante, Zante, 27 febbraio; c) Perizia, Zante, 26 febbraio., (in Italian).
Archivio di Stato di Venezia (ASVe), 1759a,b,c. Senato, Dispacci, Provveditori da Terra e da Mar, Provveditori Generali da Mar, f. 1002 (luglio 1759-maggio 1760): a) Lettera, Prov. di Cefalonia, 1759; b) Supplica di 41 abitanti di Palichi [Palichi giugno 1759]; c) Dispaccio 61, Provveditore Generale da Mar, Cefalonia, 12 settembre, (in Italian).
Archivio di Stato di Venezia (ASVe), 1766a,b,c,d,e,f. Senato, Dispacci, Provveditori da Terra e da Mar, Prov. Generali da Mar, f. 1012 (aprile 1766-febbraio 1767): a) Dispaccio n. 86, Prov. Generale da Mar, Corfù 20 giugno; b) Dispaccio n. 97, Prov. Generale da Mar, Corfù
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-1
20 novembre; c) Supplica dei Sindici di Cefalonia; d) Polizza Argostoli, Cefalonia, 4 settembre; e) Lettera, Prov. di Asso, 25 agosto; f) Fabbisogno per il restauro del palazzo pubblico di Asso, Asso Fortezza, 25 agosto, (in Italian).
Assimaki D. and Jeong S., 2013. Ground motion amplification observations at Hotel Montana during the M7.0 2010 Haiti Earthquake: Topography or soil amplification?, Bull. Seism. Soc. Am., 103(5), 2577-2590.
Assimaki D., Kausel E., and Gazetas G., 2005. Soil-dependent topographic effects: A case study from the 1999, Athens Earthquake, Earthquake Spectra 21(4), 929-966.
Assimaki, D. and Gazetas G., 2004. Soil and Topographic Amplification on Canyon Banks and the Athens 1999 Earthquake, Journal of Earthquake Engineering, 8, 1-44.
Athanasopoulos-Zekkos, A., Vlachakis, V.S., and Athanasopoulos, G.A., 2013. Phasing issues in the seismic response of yielding, gravity-type earth retaining walls – Overview and results from a FEM study, Soil Dynamics & Earthquake Engineering 55, 59-70.
Barbiani, D.G. and Barbiani, B.A., 1864. Mémoire sur les tremblements de terre dans l’île de Zante, Mém. Academie Imperiale des Sciences, Dijon, 1-112, (in French).
Bardakis, V. (2014) Seismic response of “Mantzavinateio” Lixouri Hospital (in Greek, Απόκριση του Μαντζαβινάτειου Νοσοκομείου Ληξουρίου), Seminar, First Observations from the Cephalonia Earthquake, April 10, Athens and Lixouri
Batilas, A., Pelekis, P., Vlachakis, V., and Athanasopoulos, G., 2014. Soil Liquefaction / Nonliquefaction in the Achaia-Ilia (Greece) 2008 Earthquake: Field Evidence, Site Characterization & Ground Motion Assessment. Int. J. Geoengineering Case Histories, 2(4), 270-287, casehistories.geoengineer.org/volume/volume2/issue4/IJGCH_2_4_3
Bittlestone, R., 2005. Odysseus Unbound: The Search for Homer's Ithaca. Cambridge University Press, assets.cambridge.org/052185/3575/excerpt/0521853575_excerpt
Bouckovalas, G., 2014. Kefalonia earthquakes: Preliminary Geotechnical Reconnaissance (ppt presentation).
Briole P. et al., 2014. The seismic crisis of January-February 2014 at Cephalonia Island (Greece). Constrains from SAR interferometry. Geophysical Journal International (under review).
Chatzipetros A., Sboras S., & Pavlides S., 2014. The Cephalonia (Greece) Jan. 26, 2014 M6.1 Earthquake: Preliminary interpretation and stress transfer analysis, European Geosciences Union General Assembly, Vienna, Austria, Paper EGU2014-16820.
Dakoulas P. and Gazetas G., 2008. Insight into seismic earth and water pressures against caisson quay walls, Geotechnique, 58, 95–112.
Daltri, A. & Albini, P., 1991. L'Archivio di Stato di Venezia: studio sulla potenzialità della documentazione ivi depositata ai fini delle ricerche sui terremoti europei di interesse per il Progetto CEE "RHISE," Progress Report, 120 pp., (in Italian).
Dercourt et al., 1980. Grèce. Introduction à la géologie générale. 26 Cong. Géol. Int. Paris. Excursions 160c-162c, Livret Guide, G12, 159p, Paris
Dercourt et al., 1980. Grèce. Introduction à la géologie générale, 26 Cong. Géol. Int. Paris. Excursions 160c-162c, Livret Guide, G12, Paris, 159 pp. (in French).
EAK (2000). Greek Seismic Code, Ελληνικός Αντισεισμικός Κανονισμός, Athens, Greece, (in Greek), with an amendment in 2003.
EC-8, European Committee for Standardization, 2008. Eurocode 8: Design of structures for earthquake resistance, Doc CEN/TC250/SC8/N317, CEN.
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-2
Eginitis, D., 1916a. Les tremblements de terre de Cephalonie – Zante du 24 Janvier 1912. Annales de l’Observatoire National d’Athènes, VII, 19-22, (in French).
Eginitis, D., 1916b. Sur les tremblements de terre de Leukada et d’Ithaque 23 & 27 Nov. 1914 et du 27 Janvier 1915. Observatoire National d’Athènes, VII, 27-32, (in French).
Eleftherotypia Newspaper, 2014. Do we now repair or demolish? (in Greek, Τώρα επισκευάζουμε ή κατεδαφίζουμε;), online article by A. Tzavella dated 2/10/14, last accessed 2/20/14, enet.gr/?i=news.el.article&id=414563.
EPPO-ITSAK, 2014. The earthquake of 26/1/2014(M6.1) in Cephalonia (Greece): Strong Ground Motion, Soil Behaviour and Response of Structures, Preliminary Report, last accessed 3/24/14, itsak.gr/news/news/70
EYDAP (ΕΥΔΑΠ), 2014. Emergency support to the municipality of Cephalonia for repair of damages occurred after the January-February 2014 earthquakes, preliminary report by EYDAP’s General Department of Networks & Facilities and Departments of Potable Water Network Department and Waste Water Network / Quality Assurance (in Greek).
EYDAP (ΕΥΔΑΠ), 2014. Video documentary of EYDAP network missions to Cephalonia, last accessed 4/21/14, youtube.com/watch?v=Dyt7sZsrNYs.
FEMA (Federal Emergency Management Agency), 2011. FEMA E‐74: Reducing the risks of nonstructural earthquake damage – a practical guide
Foufopoulos, G., 2014. Personal communication of Mr. G. Foufopoulos of National Insurance Agency of Greece (Εθνική Ασφαλιστική) with GEER/EERI/ATC team members G. Tsakalias, A. Psychogiou, and S. Nikolaou, 2/11/14.
Foxnews.com, 2014. Second relief ship heads to quake-struck Greek island, online article dated 1/28/14, Associated Press, last accessed 5/23/14, foxnews.com/world/2014/
Galanopoulos, A.G., 1955. Erdbebengeographie von Griechenland. Ann. Geol. 6, 83-121, (in German).
Garini E., Makris N., and Gazetas G., 2014. Elastic and inelastic systems under near-fault seismic shaking: acceleration records versus optimally-fitted wavelets, Bulletin of Earthquake Engineering, DOI 10.1007/s10518-014-9631-z.
Gazetas G., 1996. Soil Dynamics and Earthquake Engineering – Case Histories, Symeon Publications, Athens (in Greek).
Gazetas G., Anastasopoulos I., Dakoulas P., 2005. Failure of Harbor Quaywalls in the Lefkada 2003 earthquake, Performance Based Design in Earthquake Geotechnical Engng, 16th Int. Conf. Soil Mechanics and Foundation Engineering, Osaka, 62-69.
Gazetas G., Dakoulas, P., Papageorgiou A., 1990. Local-Soil and Source Mechanism Effects in the 1986 Kalamata Earthquake, Earthquake Engineering & Structural Dynamics, 19, 431-456.
Gazetas G., Psarropoulos P., Anastasopoulos I., Gerolymos N., 2005. Seismic behavior of flexible retaining systems subjected to short duration moderately-strong excitation, Soil Dynamics & Earthquake Engineering 25, 537-550.
GEER Association, 2008. Preliminary report on principal seismological and engineering aspects of Mw=6.5 Achaia-Ilia, Greece 6/8/08 earthquake, GEER Report 013 with contributions by ITSAK, UPatras, UCLA geerassociation.org
GEER, 2011. Geotechnical Reconnaissance of 2011 Christchurch, New Zealand Earthquake, V. 01: 11/8/11, Report No. GEER-027 for web dissemination, last accessed 4/8/14, GEER_Post%20EQ%20Reports/Christchurch_2011/Index_Christchurch_2011
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-3
Geoengineer.org, 2014. Cephalonia earthquake, preliminary damage observations from Geoengineer.org's geotechnical engineer, Geoengineer.org. geoengineer.org/news-center/news/item/729-cephalonia-earthquake-preliminary-damage-observations
Geosymvouloi EPE., 2014. Geotechnical study at the Lixouri Port following the two earthquake events on 1/26/14 and 2/3/14; Report to the Greek Ministry of Transportation and Communication, Port and Airport Authority (in Greek).
Goulandris, E., 1916. Sur les tremblements de terre de Cephalonie – Zante du 24 Janvier 1912. Annales de l’Observatoire National d’Athènes, VII, 42-46, (in French).
Graseet de Saint-Sauveur, A., 1800. Voyage historique, littéraire et pittoresque dans les isles et possessions ci-devant vénitiennes du Levant, online photos accessed 5/23/14
Gre.Da.S.S. The Greek Database of Seismogenic Sources - gredass.unife.it Guralp Systems, 2009. SCREAM, Operator's Manual, Guralp Systems Limited, 1-42. Higgins, M.D. and Higgins R.A., 1996. A Geological Companion to Greece and the Aegean,
Cornell University Press. Himmerkus, F., Anders, B. Reischmann, T., & Kostopoulos, D., 2007. Gondwana-derived
terranes in the northern Hellenides, Geological Soc.of America Memoirs 200, 379-390. Hodges G., Kilcoyne D., Eddies R., Underhill J.R., 2009. Geophysics in the search for Homer’s
Ithaca, Proc., 22nd Symposium on Application of Geophysics to Engineering & Environmental Problems (SAGEEP), Fort Worth, Texas.
Hoek E., Carranza Torres C.T., and Corkum B., 2002. Hoek – Brown failure criterion - 2002 edition, Proc. North American Rock Mechanics Society, Toronto
Hoek E., Carranza Torres C.T., and Corkum B., 2002. Hoek–Brown failure criterion - 2002 edition, in Proceedings, North American Rock Mechanics Society, Toronto.
Homer. The Odyssey (Οδύσσεια), with an English Translation by A.T. Murray, 1919. Harvard University Press; London, William Heinemann, Ltd.
Iai, S., 2001. Seismic Design Guidelines for Port Structures, International Navigation Association (PIANC) ed., Balkema, 474 pp.
IGME, 1995. Geological Map of Greece – Cephalonia Sheet, 1:50,000 scale, Institute of Geology and Mineral Investigations, Athens, Greece.
Inkefalonia.gr, 2014. Matnzavinateio Hospital becomes operable starting tomorrow (in Greek, Επαναλειτουργεί από αύριο το «Μαντζαβινάτειο» Νοσοκομείο), online Article, February 5, 2014, last accessed 3/26/14
Inkefalonia.gr, 2014. The bottle which will connect the Aegean with Cephalonia! (in Greek, Το μπουκάλι που θα ενώσει το Αιγαίο με την Κεφαλονιά!), online article dated 2/24/14 by cyclades24.gr, last accessed 5/23/14, inkefalonia.gr/enimerosi/koinonia/
Institute of Geological and Mineral Exploration (IGME), 1985. Geological Map of Greece, Scale 1:50,000.
Institute of Geological and Mineral Exploration (IGME), 1989. Seismotectonic Map of Greece, Scale 1:500,000.
Karakostas, C., Lekidis, V., Makarios, Τ., Salonikios, Τ,. Issam S. and Dimosthenous M., 2005. Seismic Response of Structures and Infrastructure Facilities during the Lefkada, Greece Earthquake of 14/8/2003, Engineering Structures 27(2), 213-227.
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-4
Karakostas, C.Z., Lekidis, V.A., & Papadimitriou K., 2003. Seismic Response of instrumented R/C Buildings during the Athens (7-9-99) Aftershock Sequence, in FIB-Symposium on Concrete Structures in Seismic Regions (FIB2003), Athens, Greece.
Karakostas, Ch., Lekidis, V., Salonikios, Τ., Makarios, T., Sous, I., Papadimitriou, C., Karamanos, S., Christodoulou K. and Panetsos P., 2006. Structural Identification of Bridges Based on Ambient Vibration Measurements, in Proceedings, 1st European Conference on Earthquake Engineering and Seismology, Geneva.
Karakostas, V.G., Papadimitriou E.E., and Papazachos, C.B., 2004. Properties of the 2003 Lefkada, Ionian Islands, Greece, Earthquake Seismic Sequence and Seismicity Triggering, Bulletin of Seismological Society of America 94(5), 1976-1981.
Karamitros D.K., Bouckovalas G.D., and Chaloulos Y.K., 2013. Insight into the seismic liquefaction performance of shallow foundations, J. Geotechnical and Geoenvironmental Engineering 139(4), 599-607.
Kashima T., 2005. ViewWave (aoftware), Building Research Institute, Tsukuba, Japan. Kathimerini Newspaper, 2014. Cephalonia declared a natural disaster zone, online article dated 2/4/14, last accessed 5/23/14, ekathimerini.com/4dcgi/ Kathimerini Newspaper, 2014. Cephalonia residents to receive more than 6 mln euros in
damages, ionline article 3/28/14, last accessed 5/23/14, ekathimerini.com/4dcgi/ Kathimerini Newspaper, 2014. Greece appeals for EU aid to support quake-hit island, online
article dated 3/31/14, last accessed 5/23/14, ekathimerini.com/4dcgi/ l Kathimerini Newspaper, 2014. Olympiakos to aid quake-struck Cephalonia, online article
2/7/14, accessed 5/23/14, ekathimerini.com/4dcgi/ Katramis, N. (Κατραμής, Ν.), 1880. Φιλολογικά ανάλεκτα Ζακύνθου, Ζάκυνθος, 459-466, (in
Greek). Kavasakales, G. & Polymenakos, L. (Καβασακάλης, Γ. και Πολυμενάκος, Λ.), 1988.
Σεισμικότητα των Ιονίων νήσων. Αριστ. Παν. Θεσσαλονίκης, (in Greek). Kefaloniayachting.com, 2014. Argostoli Port Kefalonia, online article last accessed 5/23/14,
kefaloniayachting.com/argostoli-port-kefalonia/ Kefalonitis.com, 2014. Acknowledgement of Children’s Phychiatric Hospital of University of
Athens (in Greek, Ευχαριστίες της Παιδοψυχιατρικής Κλινικής του Παν/μιου Αθηνών), online article dated 5/16/14, last accessed 5/23/14, kefalonitis.com/
Keffyroots.com, 2014. A brief History of Kefalonia, online article last accessed 5/23/14, keffyroots.com/history.htm
Kinemetrics, 1999. KMI Strong motion Analyst, Document 302415, Rev. C, 1-92. Kouskouna V., Makropoulos K., 2004. Historical earthquake investigations in Greece, Annals
of Geophysics 47(2/3). Lee C.J., 2005. Centrifuge modeling of the behavior of caisson-type quay walls during
earthquakes, Soil Dynamics & Earthquake Engineering 25(2), 117-131. Lekidis V., Papadopoulos S., Karakostas C., & Sextos A., 2013. Monitored inconherency
patterns of seismic ground motion and dynamic response of a long cable-stayed bridge, Postconference book Computational Methods in Earthquake Engng, (2), Papadrakakis, Fragiadakis, Plevris, eds., Computational Methods in Applied Sciences 30, 33-48.
Lekidis, V. A., Karakostas, C.Z., Dimitriu, P.P., Margaris, B. N., Kalogeras, I., Stavrakakis G. and Theodulidis N., 1999. The Aigio (Greece) Seismic Sequence of June 1995:
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-5
Seismological, Strong-motion Data and Effects of the Earthquakes on Structures, Journal of Earthquake Engineering 3(3), 349-380.
Lekidis, V., Tsakiri, M., Makra, K., Karakostas, C., Klimis, N., and Sous, I., 2005. Evaluation of Dynamic Response and Local Soil Effects of the Evripos Cable-Stayed Bridge using Multi-sensor Monitoring Systems, Engineering Geology 79, 43-59.
Lekidis, V.A. & Manos, G.H., 1993. Observations and classification of buildings damaged by a strong earthquake, in Proceedings, International Seminar on post-earthquake emergency damage and usability assessment of buildings, Athens, Greece, 22-24.
Lekidis, V.A., 2014. The Cephalonia earthquakes (M=6.1 and M=6.0), lessons learned and recommendations based on the up to date data, Τεχνογράφημα, TEE, Technical Champer of Greece, Central Macedonia Division, 479, 10-11, (in Greek).
Lekidis, V.A., Theodulidis, N.P., Margaris, V.N., & Papastamatiou, D.J., 1992. Observations and lessons learned from recent earthquakes in Greece, in Proceedings, Tenth World Conference in Earthquake Engineering, Madrid, 1, 21-26.
Lekidis,V.A. and Anagnostopoulos, S.A., 1992. Analysis of the prefecture building in Kalamata, for the recorded accelerograms of the September 1986 earthquake, Proc., 1st Greek Congress on Earthquake Engng & Engng Seismology, II, 331-346. (in Greek)
Lekkas E. et al., 1996. Neotectonic map of Greece, scale 1:100,000 - Cephalonia and Ithaca sheet.
Lew, M., Sitar, N., and Al Atik, L. 2010. Seismic Earth Pressures: Fact or Fiction?, Invited Keynote Paper, in Proceedings, Earth Retention Conference, ASCE, Seattle, August.
Louvari E., Kiratzi A.A., Papazachos B.C., 1999. The Cephalonia Transform Fault and its extension to western Lefkada Island (Greece), Tectonophysics 308, 223–236.
Makris N., Vassilliou M.F., 2014. Are Some Top-Heavy Structures More Stable? Journal of Structural Engineering 140(5), 723-731.
Makropoulos K. & Kouskouna V., 1994. The Ionian Islands earthquakes of 1767 & 1769: Seismological Aspects. Contribution of historical information to realistic seismicity and hazard assessment, CEC Project, Review of historical seismicity in Europe, 2, 27-36.
Mallet, R., 1854. Catalogue of recorded earthquakes from 1606 BC t o1850 AD, Reports of British Association Meetings, 22, 1-176, 1852; 12, 118-212, 1853; 24, 1-326, 1854.
Margottini C., 1992. On the uncertainties of historical data and their effects in seismic hazard assessment, Proc., 10th World Conf. Earthquake Engineering, Madrid, Spain.
Michael, XVIII, 1849. Historia Epiri a Michaele nepote duce conscripta, B.G. Niebuhr, ed., CSHB, Bonn, (in Italian).
Michailovic, J., 1951. Catalogue des tremblements de terre Epiro-Albanais, Zagrab, 73 pp. Montandon, F., 1953. Les tremblements de terre destructeurs en Europe, Geneve, 195 pp., (in
French). Mountrakis, D., 1985. The Geology of Greece, University Studies Press (in Greek). Mouyiaris Ν., 1994: The seismic history of the Aegean land from 2400 BC to 1990 AD, Ph.D.
Dissertation, Univ. of Patras. 400 pp. Niel T., 2007. Ithaca theory gains support, Geoscientist 17(2), 8-10. NOA-IG, 2014. Preliminary analysis of recordings from the NOA-IG accelerographs from the
1/26/14 Cephalonia earthquake, prepared by I. Kalogeras (in Greek), last accessed 3/24/14, gein.noa.gr/Documents/pdf/Cefalonia_20140126_preliminary_web.pdf
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-6
Odysseus-unbound.org, 2014. The discovery, online article last accessed 5/23/14, odysseus-unbound.org/discovery.html
Papagiannopoulos, G.A., Hatzigeorgiou, G. D., and Beskos, D.E., 2012. An assessment of seismic hazard and risk in the islands of Cephalonia and Ithaca, Greece, Soil Dynamics and Earthquake Engineering 32(1), 15-25.
Papaioannou Ch., et al., 2006. Introduction on the Seismological Data and their Elaboration for the Compilation of the new Seismic Hazard Zoning map of Greece, Proceedings of 5th Hellenic Conf. Geotechnnical & Geoenvironmental Engineering, Xanthi, Greece.
Papathanassiou G., Ganas A., Valkaniotis S., Papanikolaou M., & Pavlides S., 2014. Preliminary report on geological effects triggered by the 2014 Cephalonia earthquake, Institute of Geodynamics, School of Geology, Aristotle University of Thessaloniki. last accessed 4/20/14, gpapatha.weebly.com/uploads/8/4/0/2/8402133/cephalonia_report
Papathanassiou, G. and Pavlides, S., 2011. GIS-based database of historical liquefaction occurrences in the broader Aegean region, DALO v1.0, Quaternary Int., Earthquake Archaeology & Paleoseismology 242(1), 115–125, photo last accessed 4/6/14, users.auth.gr/∼gpapatha/dalo.htm
Papathanassiou, G., Pavlides, S., Christaras, B., and Pitilakis, K., 2005. Liquefaction case histories and empirical relations of earthquake magnitude versus distance from the broader Aegean region, J. of Geodynamics 40(2-3), Pages 257-278.
Papazachos, B. and Papazachou, K., 1989, 1997, 2003. The earthquakes of Greece, Zitis Publ., Thessaloniki, 356 pp., 304 pp., 286 pp. (in Greek).
Papazachos, B.C., 1996. Large seismic faults in the Hellenic arc, Annali di Geofisica XXXIX(5).
Papazachos, B.C., Papaioannou, Ch. A., Papazachos, C. B., & Savvaidis, A.A., 1997b. A data bank of macroseismic information for shallow earthquakes in the southern Balkan area, 550 BC – 1995 AD. Abstr. Vol. 29th IASPEI General Assembly, Thessaloniki.
Papazachos, B.C., Papaioannou, Ch., Papazachos, C.B., & Savvaidis, A.A., 1999. Rupture zones in the Aegean region. Tectonophysics 308, 205-221.
Papazachos, B.C., Papaioannou, Ch., Papazachos, C.B., & Savvaidis, A.A., 1997a. Atlas of isoseismal maps for strong (M≥5.5) shallow (h<60km) earthquakes in Greece and surrounding area, 426BC-1995. Publ. Geophysical Lab., Univ. Thessaloniki, 4, 176pp.
Papazachos, B.C., Papaioannou, Ch., Papazachos, C.B., & Savvaidis, A.A., 1998. A data bank of macroseismic information for shallow and intermediate depth earthquakes in southern Balkan area 550 BC-1998 AD. XXII IUGG General Assembly, Birmingham.
Parcharidis, I., 2014. Co-seismic surface deformation measured at Cephalonia Island during the period 1/28 to 2/8/2014 by high resolution SAR Interferometry, last accessed 3/28/14, huaremotesensingteam.wordpress.com
Partsch J., 1892. Cephalonia and Ithaki, pp. 69-77 (in Greek). Partsch, J. 1890. Κεφαλληνία και Ιθάκη, Γεωγραφική Μονογραφία, 68-78, (in Greek). Patrasevents.gr, 2014. Good Samaritans from Patras in Cephalonia (in Greek, Πατρινοί
Σαμαρείτες στην Κεφαλονιά: Όταν ο εθελοντισμός φτάνει στα όρια του ηρωισμού), online article 2/7/14, accessed 5/23/14, patrasevents.gr/article/90093
Pavlidis, G., Arnaoutoglou, F., Koutsoudis, A., and Chamzas, C., 2010. Virtual walkthrough in a lost town – the virtual Argostoli, IASTED Computer Graphics and Imaging, Innsbruck, Austria, 5 pp.
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-7
Pelekis, P.C., 2014. Comparative evaluation of results of surface methods for determination dynamic properties of soil at seismic recording sites, Research in “Archimedes III,” Operational Program ‘Education & Lifelong Learning.’ co-financed by EU/Greece.
Pentogalos, G.E., 1973. Report on the 1766 Cephalonia earthquake, Cefalonitiki Proodos, 20-21: 171-173.
Perrey, A., 1848. Memoir sur les tremblements de terre ressentis dans la peninsula Turco-Hellenique et en Syrie, Academie Royale de Belgique, 1-73, (in French).
Pitilakis K. et al., 2006. Rehabilitation and reinforcement study of DeBosset bridge at Argostoli, Cephalonia, Directorate for the Restoration of Byzantine and Post-byzantine Monuments, Ministry of Culture, Greece.
Poulaki-Katevati D., 2009. Cephalonia before the earthquake of 1953, ΕΙΚΩΝ, 4th Ed., 233 pp. (in Greek and English)
Rovithis, E. and Pitilakis, K., 2011. Seismic performance and rehabilitation of old stone bridges in earthquake-prone areas: the case of Debosset Bridge in Greece, Proceedings, Innovations on Bridges & Soil-Bridge Interaction (IBSBI), Athens, Greece.
Schmidt J., 1867. Πραγματεία περί του γενομένου τω 1861ω Δεκεμβρίω 26η (14η), Αθήνα, 52 σ., (in Greek).
Scordilis, E.M., Karakaisis, G.F., Karakostas, B.G., Panagiotopoulos, D.G., Comninakis, P.E., Papazachos, B.C., 1985. Evidence for transform faulting in the Ionian sea: the Cephalonia island earthquake sequence of 1983. Pure Appl. Geophys. 123, 388–397.
Shebalin, N.V., Karnik, V., & Hadzievski, D., 1974. Catalogue of earthquakes of the Balkan region. I, UNDP-UNESCO Survey of seismicity of Balkan region. Skopje, 600 pp.
Sieberg, A., 1932. Untersuchungen uber erbeben und bruchschollendau im ostlichen Mittelmeergebiet. Verlag von Gustv Fisher, Jena, 163-273, (in German).
Skarlatoudis, A.A., Papazachos, C.B., Margaris, B.N., Theodulidis, N., Papaioannou, Ch., Kalogeras, I., Scordilis, E.M., & Karakostas, V. 2003. Empirical peak ground-motion predictive relations for shallow earthquakes in Greece. BSSA, 93, 2591-2603.
Sous, I.I., Lekidis, V.A. and Karakostas C.Z., 2004. Seismic Behaviour of Structures during the 2/12/2003 Vartholomio Earthquake, Greece, in Proceedings, 11th Int. Conf. on Soil Dynamics & Earthquake Engng (11ICSDEE), Berkeley, California.
Spanopoulos, I.P. (Σπανόπουλος, Ι.Π.), 1867. Περί του εν Κεφαλληνία σεισμού. Εφημερίς των φιλομαθών, Αθήνα 624, 1169-1170, (in Greek).
Stamatelos, N.Ι. (Σταματέλος, Ν.Ι.), 1870. Αι δεκατρείς μνημονευόμεναι καταστροφαί της Λευκάδος από του 1612 μέχρι του 1869, Εφημερίς των Φιλομαθών 726, (in Greek).
Stiros, S., Pirazoli, P., Laborel, J., & Laborel-Deguen, F., 1994. The 1953 earthquake in Cephalonia (Western Hellenic Arc): coastal uplift and halotectonic faulting. Geophysics 117, 834–849.
Students.ceid.upatras.gr, 2014, accessed 5/23/14, students.ceid.upatras.gr/~gef/kefalonia/ TA NEA Newspaper, 2014. Lixouri’s location on the map has been changed (in Greek, Το
Ληξούρι άλλαξε θέση στον χάρτη), online 2/22/14 article by S. Krikkis, last accessed 2/23/14, tanea.gr/news/greece/article/5089480/to-lhksoyri-allakse-thesh-ston-xarth/
TEE-ETAM-IABSE-OASP, 2014. Seminar: First Observations from Cephalonia Earthquake, April 10, Athens/Lixouri, by: ΣΠΜΕ (Greek Soc. Civil Engrs, spme.gr), ETAM (Hellenic Soc. Earthquake Engng, eltam.org), Greek IABSE section (Int. Assc. Bridge & Structural Engng, iabse.gr); EPPO (Earthquake Planning & Protection Organization, oasp.gr).
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-8
Theodoulidis N., Kalogeras I., Papazachos C., Karastathis, V., Margaris B., Papaioannou Ch. and Skarlatoudis A., 2004. HEAD v1.0: A unified HEllenic Accelerogram Database, Seism. Res. Letters 75(1), 36-45.
Theodulidis, N., Bard, P.-Y., Archuleta, R., and Bouchon M., 1996. Horizontal-to-vertical spectral ratio and geological conditions: the case of garner valley downhole array in Southern California, Bull. Seism. Soc. Am. 86(2), 306–319.
Tsitselis, E.A. (Τσιτσέλης, Η.A.), 1960. Κεφαλληνιακά Σύμμικτα, 2, 293-480 (in Greek). Tsitselis, H., 1904. Kefalliniaka symmikta. Argostoli, (in Greek) Underhill J.R.., 2008. Testing classical enigmas, Geoscientist 18(9), 4-11. Underhill, J. 2009. Relocating Odysseus' homeland, Nature Geoscience 7, 455-458. United States Geological Survey (USGS), 2002. National seismic hazard mapping program,
earthquake.usgs.gov/hazards/, reference hazard maps for ASCE7-05. Valkaniotis S., Ganas A., Papathanassiou, G., and Papanikolaou M., 2014. Field observations
of geological effects triggered by the January-February 2014 Cephalonia (Greece) earthquakes, Tectonophysics, 10.1016/j.tecto.2014.05.012 (in print)
Vcstar.com, 2014. Tents set up for homeless, online 2/4/14 article, Associated Press, accessed 5/23/14, tents-set-up-for-homeless-from-greek-earthquakes/
Vergotis P., 1867. The January 23, 1867 Cephalonia Earthquake, 15 p. (in Greek). Vergotis, P., 1867. Kefallinia, (in Greek)
GEER/EERI/ATC Cephalonia, Greece 2014 References Report Version 1 14-9
