abstracts in alphabetical order - universidad de granada

Abstracts in alphabetical order

October 3-5, 2016, Granada (Spain)

Organized by the Universities of Granada and Almeria (Spain) and Kanagawa (Japan)

11th

International Workshop on Seismic Microzoning and Risk Reduction Abstracts

1

Abstracts in alphabetical order

Characteristics of ground shaking at different sites of the Granada city (Spain)

G. Alguacil (1), F. Vidal (1), M. Navarro (2), I. Valverde-Palacios (3) and T. Enomoto (4)

(1) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12, C.P. 18071

Granada, Spain. [email protected] ; [email protected]

(2) Dept. of Applied Physics, University of Almería, La Cañada, 04120, Almería (Spain).

[email protected]

(3) Dep. Architectonics Buildings. University of Granada. Campus de Fuentenueva s/n. 18071.

Granada, Spain. [email protected]

(4) University of Kanagawa, Yokohama (Japan). [email protected]

Abstract

The city of Granada is located in the region of highest seismic hazard in Spain. We have evaluated the ground conditions in Granada urban area to assess their influence on ground motion amplification and to estimate the intensity distribution of future earthquakes in the city. Geological sections, boreholes and geotechnical parameters have been revised to determine the characteristics of the surface geological structure. Then, we analyzed the shallow VS structure (up to ~ 15 m) at 24 points from refraction seismic profiles. The Vs structure has been obtained in 13 points by joint inversion of dispersion curves (SPAC method) and H/V curves from microtremor. The sites have been classified based on several parameters: VS30, VS100, Tp and thickness of deposits Z800. The VS30 and VS100 maps show low values (<450 m / s) in 4 of the 10 analyzed sites. Thomson-Haskell method was applied to simulate1D surface ground motion using basement records of small local and moderate Italian recent earthquakes (empirical simulation method). The key engineering parameters (PGA, PGV, CAV, AI, SA and IES) evaluated from empirical simulation show the level of amplification relative to reference site, more than 2 times in all sites and about 3 times at some ones. Acceleration response spectra for the empirically simulated accelerograms show higher values than NCSE-02 proposal for a shallow event Mw = 6.3. The results obtained are a first step in the development of shake-map scenarios for Granada.

Keywords: Ground motion amplification, SPAC method, Vs structure, empirical methods,

earthquake hazards maps.

mailto:[email protected]





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Strong ground-motion parameters as related to EMS intensity

in the Euro-Mediterranean area

G. Alguacil (1), F. Vidal (1), and L. Aramburu (1)

(1) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12, C.P. 18071 Granada, Spain. [email protected] ,[email protected]

Abstract

We have calculated four characteristic strong ground motion parameters (SGMP) for 183 European accelerograms from 75 events, recorded in 105 stations, with assigned macroseismic local intensities between IV and IX (EMS). The records were extracted from the European Strong-Motion Database (ESMD) and the Italian Accelerometric Archive (ITACA). For each processed accelerogram, the following SGMP were calculated: peak ground acceleration PGA, and velocity PGV (vector module for both), Arias intensity AI (tensor trace) and spectral intensity (Housner) SI. SI is axis-dependent, so in this study it was defined as the maximum value out of SI computed for axes in eight possible horizontal orientations covering 180º. The SGMP values have a wide range of variation for each intensity degree -a similar result to those other studies-, with a distribution tending to log-normal. Therefore, we used the logarithmic mean for each intensity degree as the most probable value of the log of each SGMP (expressed in c.g.s. units) for that intensity. The EMS intensity-log (SGMP) correlations are clear and best fitted by quadratic laws. The intensity (EMS) Ie estimated for PGA is: Ie(PGA) = -3.27 (log PGA)

2 + 18.30 (log PGA) - 16.63 and for

PGV is Ie(PGV) = -2.60 (log PGV)2 + 8.63 (log PGV) + 1.86, with residuals standard

deviation r of 0.40 and 0.21 intensity degrees, respectively. The best mono-parametric estimation obtained in terms of residuals corresponds to SI, Ie(SI)= -2.40 (log SI)

2 +

8.27 (log SI) + 1.90, with r = 0.09. For all the SGMP, an apparent change of trend is systematically observed from intensity VI to VII, less clear for SI. Hence, in order to compare with the results of other authors, truncated laws with two linear fits for the ranges IV-VI and VII-IX have been obtained, but the residuals were not improved relative to the quadratic fits. It is also clear the statistical correlation between the different SGMP calculated. So we looked for new variables as linear combinations of their logarithms that explain the most of their variance. Principal component analysis yields two new variables, X as a combination of PGA and PGV (X = 0.74 log PGV + 0.66 log PGA) and Y with the four SGMP used (Y = 0.75 log AI + 0.41 log SI + 0.40 log PGV + 0.34 log PGA). The multiparametric relations obtained of the Ie with them are: Ie(X) = - 1.44 X

2 + 8.98 X - 4.97, and Ie (Y) = - 0.36 Y

2 + 3.25 Y + 1.57. The

quadratic mean residuals are 0.28 and 0.21 intensity degrees, respectively. The relations obtained in this study may be useful for estimating the intensity from recorded accelerograms. Conversely, the estimation of the most probable SGMP values where only the macroseismic intensity degree is available is also possible.

Key-words: strong ground motion parameters, EMS intensity, building behavior, shake-map



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Torrevieja risk scenario in the urban environment of Guardamar del Segura: Analysis of uncertainties.

Agea-Medina N.(1), Molina S. (1), Lang D.H.(2), Ferreiro-Prieto I. (3), Galiana-Merino J. J. (4) and Soler-Llorens J. L. (1)

(1) Dpto. Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, 03690 Alicante, Spain, [email protected]; [email protected]; [email protected]

(2) NORSAR, Department of Earthquake Hazard and Risk, Kjeller, Norway, [email protected],

(3) Dpto. Expresion Grafica y Cartografia, Universidad de Alicante, 03690, Alicante, Spain, [email protected]

(4) Dpto. Fisica, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, 03690, Alicante, Spain [email protected]

Abstract

This study provides the results of the first earthquake loss estimation scenario for the city of Guardamar del Segura (Alicante, Spain) by using the analytical methods implemented in the earthquake loss estimation tool SELENA. A simulation of the ground motion due to the 1829 Torrevieja earthquake, in terms of PGA and spectral acceleration values, has been obtained by using NGA ground motion prediction equations (GMPE). The building stock was classified according to the methodology explained in RISK-UE. The epistemic uncertainties of the analysis were accounted for by means of a logic tree. The logic tree has two branches for the uncertainty in the earthquake scenario, two branches for the GMPEs and three branches to consider the uncertainty in Vs30 (soil conditions). Results indicate large differences derived for the different earthquake loss scenarios (ELE) obtained following each branch of the logic tree. The greatest structural damages and losses are obtained when the earthquake is located in the Bajo Segura Fault zone, using Campbell and Bozorgnia NGA GMPE and if soil conditions are characterized by a low Vs30.This paper has allowed us to see how the different possible input parameters for ELE should be carefully analyzed for each case study and the importance of providing always ELE results as mean values with corresponding uncertainty.

Key-words: Seismic risk, earthquake damage, uncertainties, analytical method

Relation between welding and earthquake (On seismic response and effect of residual stress)

Shigeru Aoki(1), Katsumi Kurita(1), Shigeomi Koshimizu(2)

(1) Tokyo Metropolitan College of Industrial Technology, 1-10-40 Higashi-Ohi, Shinagawa-ku, Tokyo 140-0011, Japan, [email protected]

(2) Advanced Institute of Industrial Technology, 1-10-40 Higashi-Ohi, Shinagawa-ku, Tokyo 140-0011, Japan

Abstract

Welding is widely used for construction of structures. Welding affects the dynamic characteristics of structure. From experiment using simple specimens, the dynamic characteristics, the damping ration and the natural frequency, of specimens are








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measured. The damping ratio of the specimen with welded joint (welded specimen) is greater than that without welding (base metal). The natural frequency of welded specimen is almost same as that of base metal. Reliability for the first passage problem is examined using measured data. It is concluded that failure probability of welded specimen is less than that of base metal. On the other hand, it is well known fact that residual stress is generated near the bead. When structure with welded joint is subjected to excess seismic loading, the response includes plastic deformation. In such a case, hysteresis loop characteristic is asymmetry and displacement response grows up in one direction. The responses of the system with asymmetrical hysteresis loop characteristic are examined. It is concluded that the displacement response increases when the system has asymmetric hysteresis loop characteristic.

Key-words: welding, seismic response, dynamic characteristic, hysteresis loop characteristic, plastic deformation

Analysis of seismic vulnerability of essential buildings (class IV) in the city of Granada

Arto, I.

COAAT Granada, GTEI Granada; [email protected]

Abstract

It is well known that to reduce risk and improve the response to a seismic event, we must know the behavior of buildings and in particular those classified as essential. For this purpose, it has been done in Granada an analysis of the vulnerability of essential buildings in the city, importance class IV as indicated by Eurocode 8. This study is part of an agreement signed between the City Council, the University and Technical Professionals Collectives of the city of Granada. In order to achieve this, they have developed a series of reports by technical volunteers assigned to the Technical Building and Infrastructure Group. The data and results have been included in the Plan with seismic emergency in the city of Granada, PLAMSIGra. For the valuation of the buildings was used Risk-UE method based on the vulnerability index, obtaining a classification of buildings according to the EMS-98. The data obtained during this analysis serve municipal protection services to improve the conditions of the essential buildings (class IV), or even to rule out its use in the case of being dedicated to hosting displaced or be Advanced Command Posts during post-earthquake management.

Keywords: Vulnerability, Risk Reduction, RISK-UE, Importance class IV.

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Seismic assessment of high-rise URM buildings: a probabilistic approach

Avila-Haro, J.A. (1), González-Drigo R.(2), Pujades, L. (3), Barbat A. (3)

(1) Dept. of Strength of Materials and Structural Engineering (RMEE), Technical University of Catalonia-BarcelonaTech (UPC), [email protected]

(2) Dept. of Strength of Materials and Structural Engineering (EEBE), Technical University of Catalonia-BarcelonaTech (UPC), [email protected]

(3) Dept. of Civil and Environmental Engineering (DCEE), Technical University of Catalonia-BarcelonaTech (UPC)

Abstract

The definition of the seismic demand and the correct characterization of the mechanical properties of the materials are two of the major difficulties in the seismic damage assessment of unreinforced masonry buildings due to the large uncertainties and variability that they present. A seven-story unreinforced masonry building in Barcelona, Spain, is taken as a case-study and modeled as an isolated solid clay structure with unidirectional iron beams-brick vaults slabs and load-bearing walls. In order to overcome the material definition shortcomings, the compressive strength, Young modulus, shear modulus and shear strength are modeled as random variables. On the other hand, the seismic demand variability is addressed through a set of different ground motions selected with the conditional spectrum method and subsequently scaled to different levels of demand (pga) as the incremental dynamic analysis methodology suggests. Due to computational and time limitations, a sufficiently representative sample is selected firstly from the population of mechanical properties, and secondly from the population of dynamics analyses for each direction of analysis. The obtained results show the correlation and different grades of influence for each of the selected random variables and levels of seismic demand (pga).

Key-words: unreinforced masonry, probabilistic approach, incremental dynamic analysis

Calculation and Interpretation of the H/V spectral ratio along

the Venta Pampanico- Guardias Viejas profile (AL-03, Campo de

Dalias, Almería)

R. Candela-Medel (1), A. García-Jerez (1,2), M. Navarro (1,2), H. Seivane (2)

(1) Instituto Andaluz de Geofísica, C/ Profesor Clavera, 12, CP 18071, Granada ([email protected])

(2) Universidad de Almeria, Dpto. Química y Física, CITE II-A, La Cañada, Spain ([email protected]; [email protected], [email protected])

Abstract

The Horizontal-to-Vertical (H/V) spectral ratio of ambient noise (Nakamura, 1989) has been obtained along a N-S seismic profile carried out in Campo de Dalías (Almería province). A total of 22 recording points with average interspace of 500m were surveyed by means of this technique. Most of the curves show clear peaks with predominant periods ranging from 0.5 s to 2.7 s. The general trend of this variation agrees well with the thickness of the Neogene and Quaternary sediments inferred from boreholes and the pre-existing active seismic survey. Furthermore, the local







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subsoil seismic velocity structure has been modelled by inversion of the experimental H/V curves using an innovative method. Average S-wave velocities have been calculated for the main geological units. Keywords: HVSR method, ambient noise, seismic velocity structure

Tools for the prevention and seismic risk reduction in Italy: study of seismic microzonation (SM) and analysis of Limit

Condition for the Emergency (LCE) of the urban settlement.

Capriglione U. (1), Gómez-Lopera S.,Á,(2), Sepede G. (3)

(1) Regional service of Civil Protection of Molise, [email protected] (2) Dep. Of Applied Physics. Polytechnic University of Cartagena (UPCT).

ETSIA, Campus Alfonso XIII, 30203, Cartagena (Spain) [email protected] (3) Dep. Of Applied Physics. Polytechnic University of Cartagena (UPCT). ETSIA, Campus Alfonso XIII, 30203, Cartagena (Spain) [email protected]

Abstract

In this paper prevention and reduction tools in the seismic risk used in Italy are presented, the study of Seismic Microzonation (SM) and analysis of the Limit Condition for the Emergency (LCE). If on the one hand the SM takes into account the geophysical, geological and site response, the purpose of the LCE it is the analysis of interference existing in a given area at communal level, between the constructed and the accessibility infrastructure as strategic buildings and civil protection areas. For this reason, and based on the experience of earthquakes, L'Aquila (2009) and Amatrice (2016), where they encountered difficulties both in first aid phase and the management emergency, the Italian has supported specific funding measures for the mitigation of seismic risk (SM and LCE) making them mandatory in all municipalities in which Ag (acceleration) is not less than 0.125 g. After a thorough review of the state in the field of SM and LCE in Italy, we can conclude that SM and LCE plays the main filing mode of urban settlement for a case study applied to the City of Santa Croce of Magliano (CB, Italy) and then we propose a possible homogenization and utilization at European scale.

Keywords: LCE cards, Seismic Microzoning, Vulnerability




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Predictive earthquake ground motion equations for Southern

Spain

Pablo Castro1, Gerardo Alguacil1,2 & Francisco Vidal1,2

(1) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12, C.P. 18071

Granada, Spain. [email protected], [email protected], [email protected],

(2) Dept. Física Teórica y del Cosmos. University of Granada.

Abstract

Ground motion prediction equations on rock have been obtained as a function of magnitude and distance for Southern Spain. The parameters selected are Peak Ground Acceleration, Peak Ground Velocity, Arias Intensity, Root Mean Square Acceleration, Spectral Intensity. We used 735 Broad-Band records of 161 earthquakes of Mw 3.7-6.3 and with a distance range from 10 to 400km. These equations show a stronger dependence on the distance than most previously published relations for Europe, Japan and the USA. Our predicted values are higher for short distances (<50km) and lower for distances beyond that, as compared with them.

Key-words: predictive equations, strong ground motion, seismic attenuation, Southern

Spain.

Capacity curve based damage index for steel buildings. A probabilistic approach

Diaz-Alvarado S.A., Pujades L.G., Barbat A.H., Hidalgo-Leiva D.A, Vargas Y.F.

Polytechnic University of Catalonia (UPC). DECA-ETCG. Barcelona Tech, Spain. [email protected]; [email protected]; [email protected].

[email protected]. [email protected]

Abstract

The capacity and expected seismic damage of several types of steel buildings are assessed by using a probabilistic approach. Nonlinear static and dynamic analyses are performed by means of Monte Carlo Simulations. Concerning to the nonlinear static approach, it is shown that a new damage model, recently developed for reinforced concrete buildings, also holds for steel buildings. The new damage index is defined as a combination of the energy dissipation and the one of the secant stiffness degradation; both functions are obtained from the capacity curve in a straightforward way. The analyzed buildings are archetypal of the Mexico City and the seismic actions are selected so that they are compatible with the design spectra provided in the seismic code. The results show that, in average, the Park and Ang index, calculated by means of incremental dynamic analysis, is well fitted by the combination of the contributions to damage of the stiffness degradation (71%) and the one of the energy loss (29%). The obtained results confirm that the new damage model can be a powerful tool for probabilistic assessments of seismic damage. Key-words: nonlinear structural analysis; Monte Carlo simulation; steel buildings; damage assessment; Park and Ang index.









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Basic Concept of Seismic Microzoning and its Recent Application for Earthquake Disaster Prevention Measures of

Local Government in Japan

Takahisa Enomoto(1), Iware Matsuda(2), Rahimian Mahmood(3), Hidekazu Sugihara(4)

(1) Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa, Yokohama, 221-8686, Japan, [email protected]

(2) Emeritus Professor of Kanto-Gakuin University, [email protected] (3) Ritsumeikan Asia Pacific University, 1-1 Jumonjibaru, Beppu, Oita, 874-8577,

Japan, [email protected] (4) Kanagawa Prefectural Office, 1 Nihon Ohodori, Naka, Yokohama, 231-8588,

Japan, [email protected]

Abstract

In Japan, the detailed earthquake damage assessment was started in the age of 1960s. A phase of earthquake disaster was divided into four stages. OutIines of each stage were given along with some examples. Also, a variety of measures to counter an earthquake disaster explained in line with its phase. It is emphasized that comprehensive measures are indispensable to mitigate earthquake damage. In this approach, it was always considered the useful and applicable results of earthquake damage assessment and the disaster prevention measures. So, we would like to introduce an recent example of earthquake damage assessment performed in a local government in Japan.

Key-words: Earthquake Damage, Measures, Seismic Microzoning, Damage Assessment

Preliminary Report of Damages by the 2016 Kumamoto Eq., Sequential Mw6.2 and Mw7.0, and Estimation of

Surrounding Soil Structures by Array Microtremor Observation

Takahisa Enomoto(1), Ma He(1), Shun Inoue(1), Tetsushi Inubushi(1), Yoshiya Oda(2), Tsutomu Ochiai(3), , Manuel Navarro(4), Francisco Vidal(5)

(1) Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa, Yokohama, 221-8686, Japan, [email protected], [email protected], [email protected],

[email protected] (2) Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo, Japan 192-0397,

[email protected] (3) Kozo Keikaku Engineering Inc., 4-38-13 Hon-cho, Nakano-ku, Tokyo 164-0012, Japan,

[email protected] (4) Almeria University, La Cañada de San Urbano 04120 Almería, Spain, [email protected]

(5) Granada University, Campus Universitario de Cartuja 18071 Granada, Spain, [email protected]

Abstract

An earthquake wit Magnitude Mj6.5 (Mw6.2) was occurred in 21:26, 4th of April, 2016 at Kumamoto Prefecture, Kyushu Island, south-west part of Japan. Its focal depth was 11km. The maximum seismic intensity (Ij) 7 was recorded at Mashiki Town, Kumamoto Prefecture. This Earthquake is decided to the foreshock of Kumamoto Eq.













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After the earthquake, we performed the damage investigations, 3 times at April, May and July in disaster areas and we recognized the damage distribution. The areas where concentrated the damages were distributed in belt zone located from Mashiki Town, Nishihara Village to Minami-Aso Village in Kumamoto Prefecture. There are active faults, Futagawa Fault and Hinagu Fault System, and especially, the damage concentrated belt zone was located on the Futagawa Fault System. We confirmed the dislocations of seismic fault at several places. In August, the microtremor miniature array observations were performed in Mashiki Town, the most damage concentrated area, and investigated the surface soil structures. Finally, we would like to discuss the relationship between the damage distribution and soil conditions.

Key-words: 2016 Kumamoto Eq., Damage Distribution, Active Fault System, Surface Soil Structure, Microtremor Array Observation

Earthquake Damage Scenarios for Granada city (Spain)

Feriche, M.(1) ; Vidal, F(1).; Azañón, J.M.(2) Navarro, M.(3)

(1) Instituto Andaluz de Geofísica, University of Granada, Campus Cartuja s/n, 18071 GRANADA Spain. [email protected] , [email protected]

(2) Dept. Of Geodynamics, University of Granada, Campus Fuentenueva s/n. 18071. Granada, Spain. [email protected]

(3) Dept. of Applied Physics, University of Almería, La Cañada, 04120, Almería, Spain. [email protected]

Abstract

Some earthquakes in 2009 L’Aquila (Italy) Mw 6.3; 2011 Lorca (Spain) Mw 5.2 and 2016 Amatrice (Italy) Mw 6.2 are a recent example of moderate magnitude earthquake destructiveness, triggering alarms among institutions of prevention and reduction of earthquake damage. Granada city (Southern Spain) is sited in the zone of highest seismic hazard in Spain, according to the Spanish seismic code (NCSE-02, 2002), with an expected (rock) acceleration of 0.24g in 475 years. Nevertheless, the occurrence of strong motions in Granada has long return periods and no accelerograms of damaging earthquakes affecting the city are available up to date. Hence, in order to estimate two potential Earthquake Damage Scenarios (EDS) for Granada city (Southern Spain) two events similar to historical ones of the 1431 (I0 ≥IX) and 1806 (I0=VIII), with epicentres nearby Granada, were chosen as scenario earthquakes. Reliable earthquake ground motion scenarios (in PGA and intensity) have been evaluated for each event applying amplification factors. These factors were obtained considering geotechnical, geophysical and VS30 data. The Building Typology Matrix (BTM) and the Vulnerability Index Vi methodology of Risk-UE project (Level I) were calibrated with post-earthquake damage data from Lorca (2011) and applied for vulnerability assessment of Granada building stock considering structural typology, age, symmetry, number of stories, and other characteristics. Finally, Damage Probability Matrix was applied to estimate EDS for each reference earthquake. Earthquake ground motion and damage scenarios have been implemented in a GIS for planning prevention policies. The highest building damage are predicted in the old masonry buildings located in the historical quarters of the city putting in evidence the great influence of building vulnerability.

Key-words: Vulnerability Index, Earthquake Damage Scenarios, Granada.





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Emergency Military Unit UME EARTHQUAKE RESPONSE

Captain Pascual Galera Cordoba

Cuartel General de la UME, Base Aerea Torrejon de Ardoz (Madird), [email protected].

Abstract

Armed Forces have already been dealing with all kind of disaster and relief operations, such as floods, wildfire and earthquakes, either within Spain or abroad. Nevertheless, the scope has now changed: they are not going to be used anymore in a sole support role: on the contrary, they have, with the Emergency Military Unit (UME), achieved the capability to be employed in the front line in case of any emergency.

Key-words: Earthquake Response, Armed Forces, Emergency Military Unit,

HV-Inv: a tool for forward calculation of the HVSR and

inversion of Vs structures under the diffuse field assumption

Antonio García-Jerez(1,2), José Piña-Flores(3), Francisco Sánchez-Sesma(3), Francisco Luzón(1,2), Manuel Navarro(1,2), Enrique Carmona(2) and Helena

Seivane(1)

(1) Universidad de Almería, Dpto. Química y Física, CITE II-A, La Cañada, Spain [email protected]

(2) Instituto Andaluz de Geofísica, C/ Profesor Clavera, 12, CP 18071, Granada. (3) Instituto de Ingeniería, UNAM, CU, Coyoacán, CP 04510, D.F. México.

Abstract

A connection between the H/V spectral ratio of ambient noise (HVSRN) and the elastodynamic Green’s function has been recently stated from the fundamentals of the ambient noise interferometry. Within this framework, we have developed and tested HV-Inv. This is a computer code for forward calculation of the HVSRN and inversion of Vs profiles for diffuse wavefields. The forward-calculation method requires numerical computation of the imaginary part of the Green’s functions in the frequency domain for coinciding source and receiver. The algorithm employed performs contour integrals in the complex wavenumber plane and separate calculation of the contributions of Rayleigh, Love, P-SV and SH waves. The stability of the algorithm at high frequencies is preserved by means of an adaptation of the Wang’s orthonormalization method to the calculation of dispersion curves, surface-waves medium responses and contributions of body waves. This algorithm has been combined with Monte Carlo sampling, simulated annealing, downhill simplex and interior point methods to make up a powerful tool for passive seismic surveying. We show examples of application to passive exploration of Low Andarax Valley and Campo de Dalías coastal plain (SE Spain).

Key-words: Diffuse wavefields, passive exploration Andarax Valley, Campo de Dalías



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Seismic damage assessment of URM buildings: A comparison of non-linear static procedures

González-Drigo R. (1), Avila-Haro J. (1), Pujades L.G. (2), Barbat A.H. (2)

(1) Dept. of Strength of Materials and Structural Engineering. EEBE-UPC BarcelonaTech. Barcelona, Spain.

(2) Dept. of Civil and Environmental Engineering. ETSECCPB-UPC BarcelonaTech. Barcelona, Spain.

Abstract

In the scientific literature, a significant number of non-linear procedures are proposed in order to evaluate the seismic vulnerability of a building. In this work, and in the context of the Risk-UE methodology, a complete comparison of six representative non-linear procedures, applied to an unreinforced building, has been performed. The incremental dynamic analysis has been considered in order to provide a reference for comparisons. Additionally, the evaluation of the applicability and reliability of the non-linear static procedures has been performed and, some simple modifications, oriented to improve their use, have been proposed. The seismic demand has been conveniently defined applying the conditional spectrum approach procedure. Two different methodologies were used in order to define the fragility curves. Accordingly, a complete comparison of the calculated damage indices and the damage curves, corresponding to the different considered peak ground acceleration values, has been undertaken. The comparison results let know that the damage curves obtained by performing the non-linear procedures and by applying the Risk-UE methodology tend to overestimate the damage corresponding to low values of the PGA while the damage related to higher values of the PGA is underestimated. Key-words: Non-linear static procedures; incremental dynamic analysis; unreinforced masonry conditional spectrum approach; multi stripe analysis

Evaluation of seismic damage in low-rise buildings of

reinforced concrete masonry

Hidalgo-Leiva D.A., Pujades L.G., Barbat A.H., Diaz-Alvarado S.A., Vargas Y.F.

Polytechnic University of Catalonia (UPC). DECA-ETCG. Barcelona Tech, Spain. [email protected]; [email protected]; [email protected].

[email protected]. [email protected]

Abstract

The assessment of damage caused by earthquakes in structures, requires the use of nonlinear analysis, either static or dynamic, in order to define the performance of the buildings for the considered hazard levels. In this paper, different damage models based on static and dynamic nonlinear analysis are used in the evaluation of a low-rise building with reinforced concrete masonry, which is the main structural material used in Costa Rica. The fragility curves and the mean damage index are defined from the static nonlinear analysis. The Park&Ang index is also obtained as a global damage index when the dynamic nonlinear analysis is performed. Damage is then described with discrete damage states and, for each damage state, displacement thresholds are






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defined. Finally, a Park&Ang compatible damage curve is obtained as a combination of the secant stiffness degradation and the plastic displacement energy curves, all obtained from the capacity curve obtained with Pushover analysis.

Key-words: Damage, Nonlinear, Damage Model, Masonry

Evaluation of Dynamic Characteristics of the Building No.3 in Yokohama Campus of Kanagawa University

Tetsushi Inubushi 1, Takahisa Enomoto 2, Sei Sato 3 and Toshio Kuriyama 4

(1) Research associate, Kanagawa University,Japan. Email: [email protected] (2) Professor, Kanagawa University,Japan. Email: [email protected]

(3) Technical Link Corporation, Yokohama, Japan, Email: [email protected] (4) Kozo Keikaku Engineering Inc., Tokyo, Japan, Email: [email protected]

Abstract

In the evaluation of earthquake behavior and seismic performance of the building, understanding of the vibration characteristics such as natural frequency and damping coefficient is essential. We analyzed the natural frequency and damping coefficient of building No.3 located in Yokohama-Campus of Kanagawa University using microtremor observation, forced vibration test, and earthquake observation records. As these results, although all observation records are small amplitude level, amplitude dependency into the horizontal 1st natural frequency was observed clearly. Meanwhile, amplitude dependency into damping factor of 1st natural vibration mode was not observed.

Key-words: Microtremor measurement, Forced vibration test, Earthquake observation, Dynamic characteristic, Dynamic interaction

The seismic response characteristics of the surface ground and structures assesed by micro-tremor measurements

-THE 2006 MID JAVA EARTHQUAKE-

T. Iwatate (1), Y.Oda (2) and M.Yoshimine (3)

(1) Professor Emeritus,Tokyo Metropolitan University, Japan, [email protected] (2) Associate professor, Tokyo Metropolitan University, Japan, [email protected]

(3) Associate professor, Tokyo Metropolitan University, Japan, [email protected]

Abstract

In Tokyo Metropolitan University, micro-tremor measurements were conducted in the areas devastated by the May 2006 Mid Java Earthquake (Mw of 6.3 with an epicentral depth of 10km hit Jogjakarta City),in order to estimate the correlation between the results of the measurements and the damages. We showed that we could estimate the seismic response characteristics of the surface ground over the huge area and there was strong correlation between those two overall. The reason why we could not see some correlation in a particular area is seemed to be because of the souse property and the propagation property. Specially, in landslide region, we could roughly

mailto:%[email protected]







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estimate the amount of sliding soil mass using the results of micro-tremor measurements and the quarter-wave length method. Besides, we could estimate the seismic response characteristics of some structures (the small Hindu historic temples, the dams and the typical houses made of brick). Key-words: The May 2006 Mid Java Earthquake, Micro tremor measurements, Geophysical exploration, Seismic response characteristic of surface ground

The Outline and The Disaster Investigations of The 2016 Kumamoto Earthquakes

Takahiro Iwatate (1), Takahisa Enomoto (2) and Koji Sato (2)

(1) Professor Emeritus,Tokyo Metropolitan University, Japan. [email protected] (2) Professor, Kanagawa University, 3-27-1 Rokakubashi Kanagawa-ku, Yokohama, 221-8686,

Japan, [email protected]; [email protected]

Abstract

The Kumamoto Earthquakes which are a series of earthquakes, including the April 14 foreshock with Magnitude 6.5(EQ.1), the April 16 main shock with Magnitude 7.3(EQ.2) occurred beneath Kumamoto city of Kumamoto prefecture in Kyushu Region, Japan. These earthquakes were occurred caused by two plates slipping against each other along the two active inland faults (Hinaku fault and Futagawa fault) (1)t least 49 people lost their lives and more than 3,000 people were injured in total

(2) Severe damages (Kumamoto castle, wooden-houses, bridges, landslides, liquefaction and etc.) were occurred by these earthquakes concentrated on the Kumamoto city, Mashiki-chyo, Minami Aso-mura and outskirts area along Hinagu fault and Futagawa fault. I went to the suffered- area in Kumamoto Region to investigate the damages structures and ground from 11 to 14, May together with professor T.Enomoto and K.Sato. This paper shows the outline of Kumamoto Earthquake and the brief-results of our investigations.

Key-words: Kumamoto Earthquake, Earthquake Observation Futagawa&Hinadu Faults, Large scale landslide

Monitoring Aseismic Surface Creep along the Western Valley (Marikina) Fault

K. KURITA(1), Y. KINUGASA(2), T. DEGUCHI(3), R. E. RIMANDO(4), M. WATANABE(5)

(1) Tokyo Metropolitan College of Industrial Technology, JAPAN, [email protected] (2) Association for the Development of Earthquake Prediction, Tokyo, JAPAN

(3) Nittetsu Mining Consultants Co., Ltd., 4-2-3 Shiba, Minato-ku, Tokyo, JAPAN (4) Philippine Institute Volcanology and Seismology, PHIVOLCS Bldg., C. P. Garcia Ave.,

University of the Philippines Campus, Diliman, Quezon City, PHILIPPINES (5) Tokyo Metropolitan University, 1-1-1 Minamiosawa, Hachioji City, Tokyo, JAPAN

Abstract

To clarify fault creep trigger along a creeping segment of the Marikina Valley fault system (MVFS) on the south-eastern part of Metro Manila, Philippines, ground


javascript:%20addrSendMail('Takahisa%2520Enomoto',%20'enomot01%2540kanagawa-u.ac.jp');



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deformation has continuously been monitored through periodic leveling surveys since 1999 and through creepmeters installed across the MVFS' creeping zone since 2008. From the creepmeter at the JUA site, the average slip rate is 1.90cm/y. This is consistent with the results of the periodic leveling surveys. However, a change in displacement for the period from September to December 2014, which coincides with the rainy season, is related to rainfall. Periodic leveling surveys shall continue and additional continuous creep measurement sites will be established to provide more bases for evaluation.

Key-words: Fault creep, Monitoring, Slip rate, Vertical ground displacement

Development of a Simple Seismic Isolation System for Art Objects

K. KURITA(1), Y. SATO(1), S. AOKI(1), M. KANAZAWA(2)

(1) Tokyo Metropolitan College of Industrial Technology,1-10-40 Higasi-Oi, Shinagawa-ku, Tokyo, JAPAN, [email protected], [email protected]

(2) Kanazawa Seisakusho Co., Ltd., 7-7-9 Nishi-Gotanda, Shinagawa-ku, Tokyo JAPAN

Abstract

In order to popularize a seismic isolation system in the museum that prevents overturning of art objects by seismic ground motion, a simple seismic isolation system that consists of superimposed two metal plates was proposed in this study. And vibration characteristics of the system was investigated by excitation experiment, was evaluated by numerical analysis. Also effectiveness of the system installed a vase on was investigated by excitation experiment. In excitation experiment, the response acceleration amplitude on the system under a friction coefficient μ=0.12 was enough reduced in case of input waves with the peak acceleration amplitude of over 400 Gal. In numerical analysis, reduction effects of the system depended on the friction coefficient, was effective with decreasing of friction coefficient. However, a relation between the peak acceleration amplitude and the peak relative displacement indicated a trade-off. Next, effectiveness of overturning prevention for art objects was investigated by excitation experiment. The results that installed the vase, the overturning acceleration is about 400 Gal, on the system indicated good performance to decrease the response against seismic ground motion. And overturning of the vase was prevented. This system is effective to prevent overturning of art objects in the museum.

Key-words: seismic isolation, art object, overturning acceleration, overturning prevention

Study on estimation of the ground structure of Sagami Plain by using array microtremor observations (CCA method)

He MA.(1), Takahisa ENOMOTO (2), Tetsushi INUBUSHI (3), Shigeki SENNA (4), Tsutomu OCHIAI (5)

(1) Doctoral Student of The Graduate School of Engineering. Kanagawa University.JAPAN, [email protected]




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(2) Professor. Faculty of Engineering. Kanagawa University. JAPAN, [email protected]

(3) Research Associate. Faculty of Engineering. Kanagawa University, JAPAN, [email protected]

(4) Researcher. National Research Institute for Earth Science and Disaster Prevention. JAPAN [email protected]

(5) Researcher. KOZO KEIKAKU ENGINEERING Inc. 4-38-13, Honchou, Nakano, Tyokyo 164-0012 JAPAN. [email protected]

Abstract

For the relief of earthquake disaster it is very important to understand the structure of the surface soil. For that reason, various methods have been used. For example, method based on the topography and geological map, method of using a large number of boring data, or method based on geophysical exploration results and microtremor observations. If the evaluation of broad-ground structure of seismic micro-zoning, either method is also pointed out weaknesses and strengths. It has been considered to be important to understand comprehensively these results. In this research, we estimated the surface soil structure of Sagami plains by using the newly developed minimum microtremor array exploration method.

Key-words: microtremor, array, Sagami Plain, H/V, Predominant period, Two-dimensional S-wave velocity view

Shallow velocity structure of Adra town (SE Spain) from MASW and SPAC methods

Pedro MARTÍNEZ-PAGÁN1*, Manuel NAVARRO2,3, Jaruselsky PÉREZ-CUEVAS1, Antonio GARCÍA-JEREZ3, Francisco VIDAL3

(1) Universidad Politécnica de Cartagena (Spain), [email protected]; [email protected]

(2) University of Almería (Spain), [email protected]

(3) Instituto Andaluz de Geofísica, University of Granada (Spain), [email protected]; [email protected]

Abstract

Shear-wave velocity (Vs) structure is a key parameter to evaluate and characterize the soil condition and its dynamic behavior that is currently applied to seismic hazard assessment. In this context, two different seismic methods were used to provide, by means of inversion of Rayleigh wave dispersion data, the Vs structure and the Vs30 parameter. These seismic methods were the multichannel analysis of surface waves (MASW), and the spatial autocorrelation (SPAC). The SPAC measurements were carried out at four open spaces providing a 1-D shear-wave velocity model at each site. The MASW method was conducted through the streets of Adra town with a total of 3.5 kilometers of seismic profiles which enabled to obtain 2-D shear-wave velocity sections from the main geological structures of the town. A detailed geological survey was of assistance for accurate 2-D interpretations and soils classifications. As consequence, a detailed microzonation map of ground conditions of Adra town has been obtained whose results will be applicable to seismic risk management and urban use planning of the town.

Key-words: Vs structure, MASW method, Adra (spain),











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The seismic loss estimation tool SELENA. New improvements and recent case study for Adra (Almeria)

S. Molina(1), D. H. Lang(2), M. Navarro(3,4), A. Meslem (2), F. Vidal(4), P.

Martínez-Pagan(5), D. Navarro(6), and N. Agea-Medina(1)

(1) Universidad de Alicante, Spain. [email protected]; [email protected];

(2) NORSAR, Department of Earthquake Hazard and Risk, Kjeller, Norway, [email protected], [email protected]

(3) Universidad de Almería, 02120 Almería, Spain, [email protected] (4) Instituto Andaluz de Geofísica, Universidad de Granada, Spain [email protected]

(5) Universidad Politécnica de Cartagena, Spain, [email protected] (6) Universidad de Sevilla, Spain, [email protected]

Abstract

Earthquake loss estimation (ELE), generally also referred to as earthquake risk assessment, is a comparably young research discipline which, at first, relied on empirical observations based on a macroseismic intensity scale. Later, with the advent of methodologies and procedures that are based on theoretical simulation in estimating physical damage under earthquake loading, the analytical approach for ELE was formulated. The open-source software SELENA, which is a joint development of NORSAR and the University in Alicante (Spain), is undergoing constant development. One of the more recent features being included is the possibility to address topographic seismic amplification. Additionally, SELENA is being adapted to include not only new indirect methodologies to compute the performance point, as the N2 Method, but also it will be ready to analytically estimate the structural damage through direct methods that yield fragility curves as functions of intensity measure types, IMT (e.g. PGA, Sa(T)) as suggested by the SYNERGY project. This paper describes the current state of the tool and the results from a recent case study for the city of Adra (Almería-Spain). Our estimation indicates that after a repetition of the 1910 Adra earthquake, around 40% of the buildings in the city will be affected by complete and extensive damage. The use of SELENA and the ELE results are useful to remark the need for earthquake risk mitigation policies and emergency preparedness actions in the city.

Key-words: Analytical methods, earthquake loss estimation, SELENA, damage and loss

Social capital analysis applied to seismic risk reduction in urban areas

Daniel Navarro Cueto 1, Ismael Vallejo Villalta 1, Manuel Navarro Bernal 2

(1) Universidad de Sevilla, Spain, [email protected] (2) Universidad de Almería, 02120 Almería, Spain, [email protected]

Social capital is understood as the resources, objects or information, that a person or group could access through its social relations. Insight about it can contribute significantly for seismic risk reduction. Social groups with high social capital will implement effective and suitable measures to prevent and prepare before an earthquake strikes and they will be able to respond and recover efficiently after the disaster. In this study a methodology to measure the social capital based on social network analysis is presented and it is applied to slums in the city of Cusco, Peru.










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Key-words: Social network analysis, seismic risk reduction, Cusco, Peru.

Super High-density Seismic observations in Zushi City, Japan

Yoshiya Oda.(1), Seiya Ito.(2)

(1) Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, [email protected] (2) Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, [email protected]

Abstract

To reduce earthquake disaster, it is important to grasp information of seismic intensity in high-resolution. Although high-density seismic networks are installed in Japan, it is difficult to estimate ground motion in detail. In this paper, therefore, we conducted super- high density seismic observation in Zushi City to understand ground motions in local area. As the results, seismic response of surface ground is the length of even in an area that evaluated as same characteristics of seismic ground motion.

Key-words: super high-density, seismic observation, Zushi City, characteristics of seismic ground motion

Dynamic Characteristics of a Re-reinforced Steel Reinforced Concrete Building Based on Seismic Observation

Toshinari Ota(1), Hiroshi Watanabe(2)

(1) Graduate Student, Kanto Gakuin University, Japan, [email protected] (2) Assoc. Prof., Kanto Gakuin University, 236-8501 Japan, [email protected]

Abstract

Seismic observation have been carried out on a re-reinforced medium-rise steel rein-forced concrete building (Kawamoto-ind. Building), located at Naka ward, Yokohama, Japan, since 20 February, 2015. The purpose is to contribute to monitoring the struc-tural deterioration with age and the structural changes by experiencing various levels of earthquakes and also giving grounds for discussing the usability of the building if it should experience a very rare earthquake. The first natural period of horizontal vibra-tion of the building was considered using the records observed since 23 February, 2015. The natural periods measured during 23 February, 2015 – 7 September, 2016 were 0.67-0.79 seconds in the longitudinal direction and 0.71-0.80 seconds in the transverse direction. The natural periods increased as the measured seismic intensity increased. The natural period increased because of the earthquake on 30 May, 2015, but became stable after the earthquake. Key-words: seismic observation, existing building, seismic retrofit, first natural period





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The Porto Viejo 2016 earthquake (Mw 7.7) in the frame of the Ecuador seismic hazard

Parra H.1, Benito M. B.1, Gaspar-Escribano J.M.1, M. Luna 3, A. Staller 3

(1) Universidad Politécnica de Madrid, Spain, [email protected], [email protected], [email protected],

(2) Universidad de las Fuerzas Armadas ESPE, Sangolquí, Ecuador (3) Ministerio de Desarrollo Urbano y Vivienda del Ecuador. Ecuador

Abstract

Ecuador is located in the northwest of South America and shows both, shallow and deep seismic activity, mainly caused by the subduction of the Oceanic Nazca Plate and the presence of a complex system of active faults that generate crustal earthquakes. The last destructive event took place in the subduction zone on April, 2016, with epicenter close to Porto Viejo and M 7.7. A seismic hazard assessment study of continental Ecuador is now presented. A new area-source model containing 21 seismogenetic zones grouped into three tectonic regimes (crustal, subduction interface and subduction in-slab) is proposed. The subduction dip is particularly analyzed to provide an area-source model consistent with the physical, geological and tectonic knowledge of the study region. A Probabilistic Seismic Hazard Assessment (PSHA) approach is carried out, in terms of peak ground acceleration PGA and spectral accelerations SA(T) for periods T = 0.1, 0.2, 0.5, 1, and 2 s. The resulting hazard maps for continental Ecuador are presented for three return periods: 475, 975 and 2475 years, together with the disaggregation analysis in four province capital cities: Quito, Esmeraldas, Guayaquil and Loja. The result in Esmeraldas is compatible with the scenario of the last earthquake occurred in 2016. The coseismic displacement of this earthquake is presented together with the Coulomb Failure stress map, showing the continental zones which have been charged after the earthquake.

Keywords: Seismic Hazard; Ground-motion; Hazard disaggregation; Ecuador

Influence of surface properties of volcanic ask on stability deposits under moderate quake.

I. Plaza1, A. Ontiveros1,2, J. A. Moleón1, E. Giménez1

(1) Dept. of Physics. University of Jaén (Spain). 23071 Jaén (Spain).

(2) Instituto Andaluz de Geofísica, University of Granada. 18011 Granada (Spain).

Abstract

The majority of big strato-volcano of our planet has suffered landslides in his flanks due to volcanic and seismic activity. The deposits of volcanic ashes and thicker fragments also they are responsible for great quantity of landslides and lahars that constitute an important geological risk. These volcanic deposits are located on slopes high inclination and without vegetation. The energy released during a volcanic earthquake may be the key factor for starting a landslide. One important factor to which depends the stability of the deposits is the energy of interaction between particles that compose them. Its calculation requires the knowledge of the superficial properties on the volcanic materials. The aim of this study is to analyze the superficial




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properties of the volcanic deposits. We analyzed different active volcanoes Mt Etna, Mt Vulcano, Mt Stromboli, El Hierro, Teide, Pico de Fogo and Deception Island. It was calculated these energy of interaction for to know what deposit might produce landslide when occur an earthquake. The results showed a strong dependence of cohesion energy with the pH value, the ionic strength of the medium and chemical nature of volcanic ash. Like this, we can see that for highest pH values, the cohesion is very low. The presence of iron reduces the cohesion and the percentage of SiO2 indicates that the higher the concentration of silicon is more cohesive volcanic ash.

Key-words: landslides, volcanoes, potential zeta, Surface free energy, ash, cohesion,

earthquake.

New parametric model for capacity curves and a new capacity based damage index

Pujades L.G., Vargas-Alzate Y.F., Barbat A.H., González-Drigo J.R.,

Diaz-Alvarado S.A., Hidalgo-Leiva D.A.

(1) Universitat politècnica de Catalunya (UPC). DECA-ETCG. Jordi Girona 1-3 08034 Barcelona. Spain. [email protected]; [email protected];

[email protected]; [email protected]; [email protected]; [email protected]

Abstract

A recently proposed parametric model re-conceptualizes capacity curves as composed by linear and non-linear parts. The normalized non-linear capacity curve can be modelled by a cumulative lognormal function. While the linear part is defined by the initial stiffness, the non-linear part keeps the information about the physical degradation of the structure for increasing drifts. Besides, the non-linear part of capacity curves allows defining new curves related to energy loss and to tangent and secant stiffness degradation. It has been shown that an adequate combination of the energy loss and secant stiffness degradation functions leads to a good pointer of physical damage and, therefore, it can be used as a new damage index. This new damage index can be calibrated in such a way that it is equivalent to the well-known Park and Ang damage index, which, in turn, can be obtained from incremental dynamic analyses. In this paper the theoretical formulation of the parametric model and the one of the new damage index are reviewed first. Then the relation between the degradation of the building and the increase of its fundamental period of response is investigated, showing that the increase of the period can be also a good damage forecaster.

Key-words: Capacity curves, lognormal function, stiffness degradation, energy loss,

damage index.







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Rehabilitation of damaged timber beams with carbon fiber reinforced plastic (CFRP)

Francisco J. Rescalvo (1), I. Valverde-Palacios (2), Elisabet Suarez (1), Antolino Gallego (1)

(1) Dep. of Applied Physics. University of Granada. Campus de Fuentenueva s/n. 18071. Granada, Spain. [email protected] ; [email protected] ; [email protected]

(2) Dep. of Building Constructions. University of Granada. Campus de Fuentenueva s/n. 18071. Granada, Spain. [email protected]

Abstract

This work demonstrates how carbon composite materials can be used to strengthen existing timber beams in order to increase or recover its bending load capacity and improve its stiffness and ductility. Timber beams are commonly affected by moisture, biological attacks, are partially or totally broken, after an earthquake or simply changes its use. Classical methods of strengthening timber beams are not always practical or economical and so these elements are simply replaced at a high cost. This project investigated experimentally the use and effectiveness of fabric and laminate strips carbon fiber composites instead of the classical steel or wood reinforcement elements. Two series of experiments were carried out. Firstly, a total of 10 beams 4.5 meters length were subjected to 3 point bending tests, 2 of them unreinforced as control specimens and 8 reinforced with 2 different layouts; one consisted in unidirectional strips attached to the bottom side (tension zone) and other consisted to add additional unidirectional fabric to both lateral sides and bottom side of the beam to improve the shear capacity. In all cases reinforcement provided a better behavior in terms of bending capacity and stiffness. Second layout provided also an important increasing of the ductility of the elements compared to the control specimens. Secondly, 6 previously broken beams were recovered and reinforced again with both layouts, and then subjected to bending tests again. Results show clearly that CFRP reinforcement provides total recovering of damaged elements in terms of bending capacity and ductility.

Key-words: Timber beams, structural reinforcement, strengthening, CFRP, rehabilitation, shear repair.

Seismic vulnerability assessment of the historical downtown buildings of Tapachula city (Chiapas) by the Vulnerability Index

Method.

J. Alejandro Ruiz Sibaja (1), Francisco Vidal Sánchez (2), Carolina Aranda Caballero (2)

(1) Universidad Autónoma de Chiapas, (Chiapas, México), [email protected] (2) Instituto Andaluz de Geofísica, Granada (España), [email protected], [email protected]

Abstract








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The seismic vulnerability of 399 buildings in 22 city blocks in the historical downtown of Tapachula have been estimated by two methods: first, the typological classification according to the European Macro Seismic Scale (EMS-98) and later by the Vulnerability Index Method (VIM) of RISK-UE project. The first one is a simple method that assigns classes of vulnerability to buildings primarily considering their type of construction based on the predominant material used in the construction of the resistant system and design level. The latter is a refined method of the first which quantifies the construction factors in a better way and the behavior of every building which modifies their vulnerability. The results obtained with both methods are presented in seismic vulnerability tables and maps, and thy show that, in the studied area, there are more than 80 % of buildings with high (B) and very high (A) Vulnerability Class. In addition, the estimate of vulnerability, according to the EMS scale criteria, is improving significantly when applying the VIM method which perceives an increase of constructions belong to Class A (from 36 to 44) and Class D (from 16 to 31) and a decrease in Class E (from 13 to 5) and Class B (from 296 to 290).

Key-words: historical downtown, building seismic vulnerability, vulnerability index method, Risk-UE.

THE DIFFUSE-FIELD ASSUMPTION TO INTERPRET THE

MICROTREMOR H/V SPECTRAL RATIO

Francisco J. Sánchez-Sesma

Instituto de Ingeniería, Universidad Nacional Autónoma de México; CU, Coyoacán, 04510 CDMX, Mexico. Email: [email protected]

Abstract

The microtremor H/V spectral ratio (MHVSR) is a popular way to estimate the dominant frequency of soil sites. This success was not without controversy because there was no clear agreement on the physical interpretation of results. In the terms of the diffuse-field theory, the average of the autocorrelations of motion components gives the directional energy densities (DED) at the site and they are proportional to the imaginary parts of the Green’s function considering source and receiver at the same location for a given direction. Here we adopt the diffuse-field assumption (DFA) and consider that microtremors are manifestations of a diffuse-field. Basically, this idea rests on multiple scattering and allows to write a formula which relate field measurements (DEDs) with intrinsic properties of systems (ImG). Moreover, this connection has physical implications that allow understanding the behavior of the MHVSR. These emerge from the duality DED-force and allow for inversion of the velocity structure. In fact, one can compute efficiently the imaginary part of the Green’s functions which are integrals along the radial wavenumber.

Key-words: Diffuse-field, microtremors, H/V spectral ratio, Green’s function.


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Evaluation of deep sediment effects through ambient noise measurements at El Ejido town (SE Spain)

H. Seivane-Ramos (1), A. García-Jerez (1), M. Navarro (1), J. Piña-Flores (2), C. Aranda (3), F. Luzón (1), F. Vidal (3) and A. Posadas (1)

1) Dept. of Applied Physics, University of Almería, La Cañada, 04120, Almería (Spain).

[email protected], [email protected] 2) Instituto de Ingeniería, Universidad Nacional Autónoma de México

3) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12,. 18071

Granada, Spain. [email protected]

Abstract

The site effects of a deep sedimentary basin case have been investigated through microtremor measurements. The main survey was focused on El Ejido town, which is located on a basin known as Campo de Dalías. In this area we carried out ambient noise recordings at 98 sites. From these measurements and by using the horizontal-to-vertical (H/V) spectral ratio technique we determined the predominant periods of the ground. Moreover, portable seismic arrays were performed at two sites to get the shear wave velocity (Vs) profiles employing the spatial autocorrelation method (SPAC) via application of an inversion algorithm. The Vs profiles reached a depth of 40 m supporting the classification of the soil as soft rock. Furthermore, by means of innovative software, deeper local S-wave velocity structures have been inverted from the experimental H/V curves for one subset of the surveyed points. All studied points in the area were found to have long natural periods ranging from 0.8 to 2.3 s. These results suggest that the predominant peaks of low frequency observed in H/V ratios are related to the impedance contrast between the entire column of sediments, whose thickness varies from 200 m in the north area to 600 m in the south area of the town,

and the basin bedrock.

Key-words: HVSR method, ambient noise, sediment depth, El Ejido.

Implementation and validation of a low-cost multichannel noise recorder

J.L. Soler-Llorens(1), J.J. Galiana-Merino(2,3) , J. Giner-Caturla(1,3), S. Rosa-Cintas(1), J. Rosa-Herranz(2,3), N. Agea-Medina(1), S. Molina-Palacios(1)

1) Dpt. Earth Sciences and Enviroment, University of Alicante, Spain. [email protected] 2) Dpt. Physics, Systems Engineering and Signal Theory, University of Alicante.

3) University Institute of Physics Applied to Sciences and Technologies, University of Alicante.

Abstract

It is well known that microzonation studies are mandatory for the evaluation of seismic hazard. Ambient noise recording methods have become a common procedure for microzonation studies but the equipment needed to record ambient noise is usually so expensive. In this work a reliable low-cost seismic noise recorder system has been implemented. The developed equipment is based in Arduino an open-source electronic development platform. The system includes an anti-aliasing filter and a selectable gain between 0 and 40dB and allows to record up to 12 differential input channels simultaneously. The





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circuit diagram and programming code are open-source, it allows other researchers to adapt the system to their special requirements. Besides, an easy to use graphical user interface has been implemented and exposed. The assessment of the developed equipment has been carried out recording seismic noise in several sites where the subsurface structure had been studied previously. Our first results confirm the performance of the developed equipment to acquire seismic noise records.

Key-words: Seismic data acquisition, seismic noise recorder, Arduino Due, open-source system, low-cost seismic recorder

Spatial distribution of earthquake-induced liquefaction and settlements in the Granada Metropolitan Area (Spain) per Title

I. Valverde-Palacios (1), F. Vidal, I (2), Valverde-Espinosa (1),D. Pradel (3)

(1) Dep. de Construcciones Arquitectónicas. University of Granada. Campus de Fuentenueva s/n. 18071. Granada, Spain. [email protected] ; [email protected]

(2) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12, C.P. 18071 Granada, Spain. [email protected]

(3) D. Pradel, Dep. of Civil, Environmental and Geodetic Engineering, The Ohio State University, 491-C Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210 [email protected]

Abstract

The Metropolitan Area of Granada (MAG), located at the north-eastern section of the Granada basin, it is acknowledged to be the most seismically active zone in Spain and seismically-induced phenomena such as liquefaction and ground settlement were reported during moderate (1806) and strong (1431) historical local earthquakes. The land beneath the urbanized areas of the MAG is located on alluvial, colluvial, silt and clay deposits with different thicknesses of granular soils and varying water table depths. We have estimated liquefaction potential index (LPI) at 104 sites on the basis of corrected SPT blow count (N1)60 values, fines content, water table depth, and the magnitude of the reference earthquake. The LPI map shows that the eastern section of the metropolitan area is not liquefiable, whereas the western one is. On the other hand, we have also estimated the earthquake-induced maximum expected settlement (S) due to densification using a recent potential correlation between S and the h/(N1)60 ratio for two reference earthquakes (magnitude 6.5 and 7.0), being h sandy soil layer thickness. Vs values have been estimated from (N1)60 data using methods proposed in the literature and tested with Vs local data from SPAC and refraction profiles. The results show predictable settlement ranging from 0.1 to 21.4 cm and up to 24.7 cm for the 6.5 and 7.0 earthquakes, respectively. These were greater than 2.0 cm and 3.3 cm in the north-central and north-western sectors of the study area, especially in the town of Atarfe and along the road between Pinos Puente and Atarfe, the same zones where settlements were observed in the 1806 earthquake.

Key-words: Liquefaction susceptibility, ground settlement, empirical methods, earthquake hazards maps.





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Influence of site response and building characteristics on earthquake damage in Viña del Mar city (Chile)

F. Vidal (1), C. Aranda (1), G. Alguacil (1), I. Valverde-Palacios (2), A. García-Jerez (3) and M. Navarro (3)

(1) Instituto Andaluz de Geofísica. University of Granada. C/ Profesor Clavera Nº12, C.P. 18071 Granada, Spain. [email protected]

(2) Dept. of Architectonic Buildings. University of Granada. Campus de Fuentenueva s/n. 18071. Granada, Spain. [email protected]

(3) Dept. of Applied Physics, University of Almería, La Cañada, 04120, Almería (Spain). [email protected] ; [email protected]

Abstract

In sedimentary basins, the periods of ground motions induced by seismic waves are strongly related with site conditions and the predominant period Tp with bedrock depth. Tp is an important parameter in the ground motion prediction equations and is a key factor to predict earthquake damage when Tp and fundamental period of buildings founded on it are close. The VS structure up to a depth of 30 m was obtained from a detailed analysis of geotechnical data in 122 sites and a VS30 classification of soils was performed according to EC-8. The Tp were estimated from ambient noise records (with the HVSR technique) in 84 points regularly spaced (∆ ~200 m) in the plain city area (on Quaternary sediments). The highest values (Tp > 0.8 s) were found nearby the Marga-Marga fault trace, and gradually decrease on both sides up to 0.4 s close hill zones, being less than 0.2 s at the hills. Two estimates of the basement depth (VS> 800 m/s) from the VS(z) and H/V observed curves show similar results: ranges from 10 to 120 m and is deeper than 50 m in one-third of the plain area, reaching 120 m in the center. The spectral amplification obtained in 12 representative sites by computing the 1-D response is > 4 in the area with greater thickness and is > 3 in the remaining area for the corresponding key periods. During the 2010 earthquake, most Viña del Mar buildings (87.7%) did not suffered substantial damage and only 252 (out of the 2054 revised constructions) suffered visible damages, and only 1.6% suffered grade 3 or 4 (EMS scale). Interestingly, only 0.9 % of the low-rise buildings (< 4 stories), the most abundant in the city (74.3 %), suffered damage and only 0.4 % were grade ≥ 3 (EMS), while medium- to high-rise RC buildings (in the 9-24 range) were the most seriously damaged ones, generally structures built before 1985 earthquake. A new set of empirical relationship between the building periods (T) and number of stories (N) were obtained after the 2010 earthquake by using ambient noise measurements on the top of 99 RC buildings (with 4<N<30). T/N relationships for undamaged and damaged buildings were found different, being the increase of T an indicator of the grade of damage. It is noted that the resonance periods of damaged buildings were into period range amplified most frequently in the subsoils located in the flat area of the city.

Key-words: Site response, building behavior, building damage, 2010 earthquake, resonance effects





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Waveform inversion of seismic refraction data to two-dimensional shallow S-wave velocity profile

Hiroaki Yamanaka (1)

(1) Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Kanagawa,Japan, [email protected]

Abstract

A waveform inversion using surface seismic data was proposed to know a two-dimensional shallow S-wave velocity profile. Seismic data (SH or P-SV wave field) generated by a surface impact observed along a line are fitted with synthetic waves computed from a finite difference forward modeling with a hybrid heuristic inversion. A shallow soil was modeled with tomographic cells and discontinuities of soft layers over a shallow homogeneous bedrock layer. The method was examined with numerical experiments and an application to actual field data. In the numerical tests several models with inhomogeneous S-wave distributions were well reconstructed by the inversion. It is also found that several stations are sufficient to deduce the S-wave velocity models using the waveform inversion. The application to the actual shallow seismic data obtained only at 8 sites along a surveying line of 35 meters long reveals a 2D S-wave velocity profile down to a depth of 10 meters. These examinations indicate a high ability of the waveform inversions for 2D S-wave profiling.

Key-words: S-wave, shallow soil, waveform inversion, seismic data


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