PIANC REPORT 2008

MITIGATION OF TSUNAMI DISASTERS IN PORTS

PIANC WORKING GROUP 53 DRAFT VERSION III AUGUST 30, 2009

PIANC WORKING GROUP 53 TABLE OF CONTENTS SUMMARY MEMBERS OF PIANC WORKING GROUP 53 ACKNOWLEDGEMENTS 1. INTRODUCTION 2. TSUNAMI DISASTERS AND DAMAGES IN PORTS 2.1 Introduction 2.2 Japan 2.3 U.S. 2.4 Mexico 2.5 Indonesia 2.6 Sri Lanka 2.7 Thailand 2.8 Turkey

2.9 Greek . GENERATION, PROPAGATION AND RUN-UP OF TSUNAMI 3.1 Tsunami generation 3.2 Tsunami propagation and transformation 3.3 Harbor resonance 3.4 Tsunami run-up 3.5 Numerical simulations 4. TSUNAMI INTRUSION IN PORTS AND INTERACTION BETWEEN TSUNAMI AND VESSELS

4.1Tsunami in port areas 4.2 Effect of tsunami on mooring/maneuvering ships

4.3 Damage to small vessels 5. INTERACTIONS BETWEEN TSUNAMIS AND PORT FACILITIES 5.1 Typical damage to port facilities in water

5.2 Typical damage to port facilities on land 5.3 Stability of port facilities against tsunami

6. RECOMMENDATIONS REGARDING TSUNAMI DISASTER MANAGEMENT IN PORTS

6.1 Strategy for tsunami disaster management in ports 6.2 Tsunami scenarios in ports

6.3 Hazard mapping from scenarios 7. RECOMMENDATIONS WITH REGARD TO WARNING AND EVACUATION IN PORTS 7.1 Tsunami warning

7.2 Evacuation of people 7.3 Evacuation of ships

8. RECOMMENDATIONS FOR STRUCTURAL COUNTERMEASURES IN PORTS 8.1 Reinforcement of port facility 8.2 Construction of tsunami defenses 9. CONCLUDING REMARKS

SUMMARY 1. Background The Indian Ocean Earthquake Tsunami which occurred on December 26, 2004 due to a huge subduction zone earthquake off the west coast of Sumatra caused devastating damage, including 300 thousand casualties. Ports in the area also suffered severe damage. Tsunami means harbor/port wave in Japanese, as tsunamis seem to appear suddenly and become very violent in shallow areas, attacking low-lying port areas that are actively used and densely populated. Port areas around the world have suffered from many tsunami disasters with large numbers of casualties. Once a tsunami disaster occurs, it can be devastating. However, since the probability of its occurrence is very low, only a very limited number of port engineers and administrative personnel have had actual experience with tsunami disasters. This means that their knowledge of tsunamis is very limited 2. Objective of this report Mitigation of disaster starts from understanding the disaster. The primary objective of the report is to disseminate knowledge about tsunamis to port engineers and administrators in order to prepare for tsunami disasters. Here we summarize the fundamental mechanics of tsunamis including simulations of tsunami generation and propagation and describe the damage that can be inflicted upon a harbor. Also presented are recommendations for disaster management in ports based on two kinds of scenarios. The scenario for current preparedness (C-Scenario) is actually disaster assessment in the current situation, which allows us to understand the existing risks including risks of damage to facilities and the impact on business. The planned scenario of a disaster (P-Scenario) is actually disaster mitigation planning in which actual and concrete target levels of Human Safety, Economic Loss and Business Continuity are determined. Measures to reach the target should be discussed and prepared including structural and non-structural countermeasures with consideration of resilience. Not only structural countermeasures but also non structural countermeasures are indispensable to mitigate very rare but severe disasters like tsunamis. Especially to save lives evacuation is vital and therefore the early warning is very important.

3. Contents of the report Chapter 2 summarizes tsunami disasters that have actually occurred in ports in the member countries. Studies are described on investigations of previous tsunami disasters in ports. Tsunami disasters occur very often along active subduction zones attacking nearby coasts and sometimes even remote coasts. Low-lying areas like ports have often suffered from severe damages, including those to port facilities and vessels. Chapter 3 explains the process from the generation of a tsunami to its run-up in order to aid understanding of the phenomena. A tsunami is a very long wave generated by deformation of the sea bottom, especially due to subduction zone earthquakes. A tsunami travels very quickly in deep sea areas and becomes violent near shore due to shoaling and breaking, and finally runs up onto land. Numerical simulations are being developed to simulate the generation and propagation of tsunamis. Chapter 4 explains tsunami behavior in ports, especially in water zones and the damage caused by tsunami, particularly to ships. A tsunami intrudes into a port with rapid currents, and significant change of the water depth can cause damage to ships. Even with tsunamis of less than 2 m in height, port areas can be damaged; in fishery and recreational ports, small boats can be washed away. With tsunamis of 3 to 4 m in height, most small boats will be washed up on the land and can collide with port facilities. Damage to hazardous facilities and cargo can become very severe. If the tsunami is higher than 4 m, the damage can be devastating. Even large vessels can be washed up onto land areas. Evaluation methods are described for the tsunami forces and mooring forces. Chapter 5 explains tsunami damage focusing on port facilities. Significant damage to port facilities can occur if the tsunami height is more than 2 m and the damage increases significantly when the tsunami height exceeds 4 m. Damage to port facilities in water is relatively small except for breakwater openings where the current is intensified. The port facilities near shore areas will be damaged severely due to the breaking tsunami front when the tsunami is more than 2 m high. In addition, studies on the stability of port facilities against tsunami actions are reviewed in this chapter. For the design of the structures against tsunamis it is important to estimate incident tsunami profile (height and current with direction). The design methods for the structures are basically the same as the design methods against waves and currents.

This means that the accumulated knowledge of Coastal and River Engineering can be used in the designs against tsunamis. Chapter 6 introduces basic concepts of tsunami disaster management in ports. What is most important is predicting the tsunami and the damage it can do in a port. A comprehensive scenario C-scernario should be prepared to predict the extent of a possible tsunami disaster for a port at its current preparedness level. Then, effective and economically feasible countermeasures can be considered to reduce the disaster and another scenario P-scenario should be made to predict what would happen if the preparedness level is raised by including planned countermeasures. The scenarios should be total/comprehensive ones with sub-scenarios covering everything from the tsunami generation to recovery of the port following a tsunami attack. Also introduced in this chapter are disaster management maps including the hazard maps that can help people grasp the scenarios, especially the inundation hazard. Robustness, redundancy and resilience of port facilities should be considered for disaster management. Chapter 7 explains evacuation from tsunami. To save lives, early warning systems for near and distant tsunamis are being developed with international cooperation for tsunami-prone regions. Proper dissemination methods of tsunami information and safe evacuation shelters and routes should be prepared for quick and safe evacuation with evacuation drills. Evacuation of ships is also important. Escape outside a port is recommended but when time is limited, strengthening the mooring is an alternative. Chapter 8 discusses the structural countermeasures in ports. Port facilities should be reinforced with consideration for tsunami attacks. Tsunami defense facilities may need to be constructed to reduce tsunami intrusion into a port and onto the land. In planning these, cost and effect should be carefully examined. Negative effects to the daily activities and environment of the port due to the facilities should also be considered.. MEMBERS OF PIANC WORKING GROUP 53 Dr. Shigeo Takahashi (Chairperson)

Executive Researcher and Director of Tsunami Research Center, Port and Airport Research Institute, Japan

Dr. Wilfred Molenaar (Vice Chairperson) Hydraulic Structures Design, Delft University of

Technology, The Netherlands Dr. Takashi Tomita, (Member and Secretary)

Tsunami Research Director, Tsunami Research Center, Port and Airport Res. Inst., Japan

Dr. Hans F. Burcharth (Member) Professor, Aalborg University, Denmark

Mr. John R. Headland (Member) Moffatt & Nichol Engineers, U.S.A.

Dr. Constantine D. Memos (Member) Professor, Maritime Hydraulics and Port Engineering, National Technical University of Athens, Greece

Dr. Subandono Diposaptono (Invited Expert) Directorate General of Marine, Coasts, and Small Islands, Ministry of Marine Affairs and Fisheries, Republic of Indonesia

Dr. S.S.L. Hettiarachchi (Invited Expert) Professor, Department of Civil Engineering, University of Moratuwa, Sri Lanka

Dr. Panitan Lukkunaprasit (Invited Expert) Professor, Dept. of Civil Engineering, Chulalongkorn University, Thailand

Dr. Ahmet Cevdet Yalciner (Invited Expert) Associate Professor, Dept. of Civil Engineering, Middle East Technical University, Turkey

Dr. Solomon Yim (Invited Experts) Professor, Department of Civil, Construction and Environmental Engineering, Oregon State University, USA.

Ing. Jose Miguel Montoya Rodriguez (Invited Expert) Head of the Port and Coastal Eng. Division, Mexican Institute of Transport, Mexico

Dr. Taro Arikawa (Invited Junior Expert) Project Researcher, Tsunami Research Center, Port and Airport Research Institute, Japan

Dr. Saman Samarawickrama (Invited Junior Expert) Senior Lecturer, Dept. of Civil Engineering, University of Moratuwa, Sri Lanka

Mr. Peter S. Rasch (Invited Junior Expert) DHI Water & Environment, Denmark

ACKNOWLEDGEMENTS The compilation of the report would not have been possible without contributions from external experts:

Professor Koji Fujima, National Defense Academy of Japan

Mr. Yuji Nishimae, Japan Meteorological Agency Dr. Takahiro Sugano, Port and Airport Research

Institute, Japan Dr. Efim N Pelinovsky, Institute of Applied

Physics, Russia Dr. Haruo Yoneyama, Port and Airport Research

Institute, Japan

Special thanks are given to Dr. R. Wim Verhagen, Chairman of MarCom Committee, Dr. Kazumasa Katoh, Member of MarCom Committee, Dr. R. Galapatti, PIANC-CoCom Representative, Mr. J.F. Kapp, PIANC-CoCom Representative, and the staff of PIANC headquarter in Brussels. Dr. Katoh was a mentor for the working group and encouraged the

compilation works. Thanks are also extended to Dr. Kazuya Watanabe, Mr. Kazuhiko Honda and Mr. Daisuke Tatsumi, the members of the PIANC WG53 secretariat within the Port and Airport Research Institute. Dr. Watanabe prepared and maintained the website of PIANC WG53 where members could discuss the contents of the draft.

AUTHORS

Chapter Authors

1. INTRODUCTION

2. TSUNAMI DISASTERS AND DAMAGES IN PORTS 2.1 Introduction 2.2 Japan 2.3 U.S. 2.4 Mexico 2.5 Indonesia 2.6 Sri Lanka 2.7 Thailand 2.8 Turkey 2.9 Greek

Dr. S. Takahashi Dr. T. Tomita Prof. S. Yim and Dr. J.R. Headland Ing. R.J.M. Montoya Dr. S. Diposaptono Prof. S.S.L. Hettiarachchi and Dr. S. Samarawickrama Prof. P. Lukkunaprasit and Dr. A. Ruangrassamee Prof. A.C. Yalciner Prof. C.D. Memos

3. GENERATION, PROPAGATION AND RUN-UP OF TSUNAM I 3.1 Tsunami generation 3.2 Tsunami propagation and transformation 3.3 Harbor resonance 3.4 Tsunami run-up 3.5 Numerical simulations

Prof. A.C. Yalciner and Dr. T. Tomita Dr. T. Tomita and Dr. S. Samarawickrama Dr. T. Tomita and Prof. A.C. Yalciner Ing. R.J.M. Montoya and Dr. T. Tomita Dr. T. Tomita

4. TSUNAMI INTRUSION IN PORTS AND INTERACTION BETWEEN TSUNAMI AND VESSELS 4.1Tsunami in port areas 4.2 Effect of tsunami on mooring/maneuvering ships 4.3 Damage to small vessels

Dr. T. Tomita Dr. J.R. Headland, Dr. Yoneyama, and Dr. Takahashi Dr. H. Yoneyama

5. INTERACTIONS BETWEEN TSUNAMIS AND PORT FACILITIES 5.1 Typical damage to port facilities in water 5.2 Typical damage to port facilities on land 5.3 Stability of port facilities against tsunami

Dr. S. Takahashi Dr. S. Takahashi and Dr. T. Arikawa Dr. S. Takahashi

6. RECOMMENDATIONS REGARDING TSUNAMI DISASTER MANAGEMENT IN PORTS 6.1 Strategy for tsunami disaster management in ports 6.2 Tsunami scenarios in ports 6.3 Hazard mapping from scenarios

Dr. S. Takahashi Dr. S. Takahashi and Dr. T. Tomita Dr. T. Tomita

7. RECOMMENDATIONS WITH REGARD TO WARNING AND EVACUATION IN PORTS 7.1 Tsunami warning 7.2 Evacuation of people 7.3 Evacuation of ships

Dr. Y. Nishimae and Dr. S. Takahashi Dr. S. Takahashi Dr. S. Takahashi

8. RECOMMENDATIONS FOR STRUCTURAL COUNTERMEASURES IN PORTS 8.1 Reinforcement of port facility 8.2 Construction of tsunami defenses

Dr. S. Takahashi Prof. C.D. Memos and Dr. S. Takahashi

9. CONCLUDING REMARKS

1. INTRODUCTION ________________________________________________________ Many people became aware of the risk of tsunamis only after the Indian Ocean Tsunami of December 24, 2004, which killed 300 thousand people. However, tsunamis occur frequently every year around the world. Figure 1.1 shows the map of earthquake centers within the recent 100 years. Large earthquakes occur mainly around the boundaries of tectonic plates which cover the earth. The major cause of tsunamis is earthquakes occurring at the edges of the plates, i.e. subduction zones which are due to the everlasting movement of tectonic plates. Tsunamis also occur due to large marine landslides and volcanic eruptions. For example, the subduction zone earthquakes off Tokai Coast in Japan occur at intervals of about 150 years. Areas that have been attacked by tsunamis in the past are very likely to be attacked again by tsunamis in the future. Tsunami is a Japanese word written with two Chinese characters. Tsu means harbor/port and nami means wave, and therefore tsunami means harbor/port wave in Japanese. The naming comes from the fact that tsunamis seem to appear suddenly and become very violent in shallow areas, attacking low-lying areas that are actively used and densely populated, i.e. port areas. Port areas around the world have often suffered from tsunami disasters with large numbers of casualties. This report was prepared to help people in such vulnerable areas protect themselves against tsunami attacks. It is especially for those responsible for the safety of the people and continuity of the business in such areas. Chapter 2 presents examples of damage due to tsunamis especially in ports to give a general view of the damage that can result from a tsunami attack. Chapter 3 explains the mechanism of tsunamis from their generation to their run-up, and Chapters 4 and 5 introduce the behavior of tsunami and its effects on port facilities. Chapter 6 presents recommendations for disaster management in ports, and Chapter 7 offers recommendations for warning and evacuation in cases of a tsunami attack. Chapter 8 discusses structural countermeasures that can be implemented for protection against tsunamis.

P

North American Pl.

Eurasia Pl.

hilippine Pl.African Pl.

Pacific Pl.

Indo-Australia Pl.

South American Pl.

Antarctic Pl.

Fig. 1.1: Epicenters within recent 100 years and tectonic plates http://j-jis.com/data/plate.shtml

2. TSUNAMI DISASTERS AND PORT DAMAGE

______________________________________________________________

2.1 INTRODUCTION Disaster prevention will start from peoples understanding of the disaster. This expresses the importance of learning from past experiences. From the 20th century, there were four huge subduction zone earthquakes exceeding M9.0. Their effects spread through oceans killing many people along the coasts. There were also many large subduction zone earthquakes ranging from M7.5 to M9 that caused devastating disasters along the coasts near the origin of the earthquake. Table 2.1 presents the recent tsunami disasters around the world. The Indian Ocean tsunami caused by an earthquake off the west coast of Banda Aceh, Indonesia in 2004 was the worst natural disaster in history killing 300 thousand people along the coasts of the Indian Ocean. In 1960, the Chilean tsunami was generated by a huge earthquake of M9.5, the largest recorded, that caused significant damage not only along the South America coasts but also all around the Pacific Ocean. In Japan, the Meiji-Sannriku earthquake tsunami in 1897 attacked the northern Pacific coasts killing 20 thousand people. More recently, the Nihokai-Chubu Earthquake Tsunami (1983) and Hokkaido Nanseioki Earthquake Tsunami (1993) attacked the Japan Sea coasts causing severe damage. Casualties were limited due to warning systems in place at the time. In the U.S., the Aleutian tsunamis in 1946 and 1957 and the Kamchatka tsunami in 1952 attacked Alaska, California and Hawaii causing more than a hundred casualties each. In Europe, the Messina Earthquake tsunami devastated coastal cities in southern Italy in 1908. This chapter presents an overview of tsunami disasters especially in ports. Damages due to tsunami vary significantly depending on the location and incident tsunami height. Port areas are very vulnerable to tsunami, and damages can occur even if the tsunami inundation level is low. Photos of tsunami disaster damage are used to support the explanations. Table 2.1: Major Tsunami Disasters

2.2 References

Borerro, J., Ortiz, M.,, Titov, V.V., Synolakis, C.E. (1997) Field survey of Mexican Tsunami, EOS, Trans. American Geophysical Union , 78 (8). 85, 8788.

Dalrymple, R.A. and D.L. Kriebel (2005): Lessons in engineering from the tsunami in Thailand, The Bridge, U.S. National Academy of Engineering, 35, 2.

Fritz, H.M., C.E. Synolakis, B.G. McAdoo (2006). Maldives field survey of the 2004 Indian Ocean Tsunami. Earthquake Spectra 22(S3):S137-S154.

Horikawa, K. and N. Shuto (1983): Tsunami disasters and protection measures in Japan, Tsunami- their science and engineering, Terra Scientific Publishing Co. Tokyo, 9-22.

Imamura F., Arikawaw T., Tomita T., Yasuda T., and Kawata Y., (2005):Field investigation on the 2004 Indian Ocean Tsunami in the southern coast of Sri lanka, Asian Paific Coasts 2005, Jeju, Korea, pp93-105.

Kawata, Y., Benson, B.C., Borrero, J., Davies, H., de Lange, W., Imamura, F., Synolakis, C.E., (1999) Tsunami in Papua New Guinea, EOS, Trans. American Geophysical Union , 80 (9) 101105.

Synolakis, C.E., and E.N. Bernard (2006): Tsunami science before and after 2004, Philosophical Transactions of the Royal Society, A, 364, 22312265, doi:10.1098/rsta.2006.1824.

Takahashi, S. (2005): Tsunami disasters and their prevention in Japan Toward the performance design of coastal defense, Proc. Int. Symp. Disaster Reduction on Coasts, Monash Univ., Australia.

The Investigation Delegation of the Japanese Government on Disaster caused by the Major Earthquake off the Coast of Sumatra and Tsunami in Indian Ocean, The December 26, 2004 Tsunami Disaster in the Indian Ocean- Report of Investigation, Cabinet Office, Japanese Government, 2005, 179 p.

Table 2.1: Major tsunami disasters

Name of Earthquake or Tsunami Year Magnitude Location Maximum tsunami heightm Number of deaths

Krakatau Volcano Explosion 1883 Sunda Straight, Java 37 36,417Meiji-Sanriku Earthquake 1896 8.5 Iwate, Japan 38.2 21,915Messina, Italy Earthquake and Tsunami 1908 7.1 Italy, Messina 70,000 Kanto Earthquake 1923 7.8 Kanto region, Japan 12 hundreds of peopleGrand Banks Earthquake 1929 7.2 South coast of Newfoundland 29 Showa-Sanriku Earthquale 1933 8.1 Sanriku, Japan 23 3,068 Tounankai Earthquake 1944 8.0 Tonankai, Japan 8 1,223 Aleutian Earthquake 1946 7.8 Aleutian Islands 30 165 Nankai Earthquake 1946 8.0 Nankai, Japan 6 1,443 Kamchatka Earthquake 1952 9.0 Kamchatka Peninsula, Russia 15 Aleutian Earthquake 1957 9. Aleutian Islands 22 Chilean Tsunami 1960 9.5 Coast of South Central Chile 25 6,000 Good Friday Tsunami 1964 9.2 Alaska, British Columbia, California, and coastal

Pacific Northwest 23 121

Moro Gulf Tsunami 1976 7.9 The island of Mindanao, Philippines. 5,000 Tumaco Tsunami 1979 7.9 along the Pacific coast of Colombia and Ecuado 259 Nice 1979 France, Nice 23 Sea of Japan (Nihonkai-Chubu) tsunami 1983 7.7 Akita, Japan 6.6 100 Okushiri, Hokkaido tsunami 1993 7.8 Okushiri Island, Japan 30 201 Papua New Guinea 1998 7.1 Papua New Guinea 12 2,200 Indian Ocean Tsunami (Asian Tsunami) 2004 9.1 Sumatra, Indonesia 38 300,000 South of Java Island Tsunami 2006 7.7 South of Pangandaran 6 540 Solomon Islands Tsunami 2007 8.1 Northwest of the Solomon Islands 5 52

2.2 JAPAN

2.2.1 Introduction

Japan has most experiences of tsunami disasters in the world. Tsunami-induced damages depend on geometry and topography as well as characteristics of tsunamis striking coasts, and disasters are caused in relation to human activities and eco-system. In this section, therefore, natural and social condition of Japan is briefly introduced at first, and then tsunami history and disasters due to recent tsunamis are described. Because disasters in many ports were caused by each tsunami, descriptions in the later sub-sections are summarized in each major tsunami.

2.2.2 Natural and Social Condition

Japan is an islands country located in the northwestern part of the Pacific Ocean. The Sea of Japan and the East China Sea separate Japan from the Eurasian continent. Total land area of Japan is approximately 378,000 square kilometers, and nearly 80% among the area is mountainous and unsuitable for agricultural, industrial, or residential use. Numerous small and narrow plains are mainly along the coasts, and majority of population of Japan reside and most human activities develop there. The coastline is totally 35,000 kilometers in length, and has various configurations: plain beaches, bays, peninsulas.

2.2.3 Tsunami history Japan is in the circum-Pacific volcanic belt of Pacific Ring of Fire, and subduction zones in which big earthquakes occur are formed by four earths crusts of Eurasian Plate, North American Plate, Pacific Plate, and Philippine Sea Plate encountering under the Japanese islands and surrounding sea, as shown in Fig. 2.1.

Fig. 2.1: Tectonic plates surrounding Japan In Japanese history, big earthquakes have occurred repeatedly along these subduction zones, and such earthquakes generated tsunamis which caused severe disasters. The earliest record in Japanese history of tsunami disaster is an event in 684 which is caused by Hakuo-Nankai Earthquake. Figure 2.2 shows Recentl earthquakes and tsunamis in Japan.

The population of Japan is 128 million people in 2008 and the majority of them live in urban areas which have been developed coastal areas. The population density in 2005 is 343 persons per square kilometer on average. Since a number of people with high density reside in coastal areas, Japan has high risk of coastal natural disasters: tsunami and storm surge. For example, Typhoon Ise-wan in 1959 exited 3.5-meter storm surge in the Ise Bay with unprecedented damage including more than 5000 people killed or missing.

A number of big earthquakes with high tsunamis have occurred along the Nankai Trough in the southern sea off the main island of Japan, in which the Philippine Sea Plate slides beneath the Eurasian Plate. Time interval of their earthquake occurrences is 100 to 150 years. Past earthquakes occurring there were M8 class: Meio Earthquake of M8.2 8.3 in 1498, Keicho Earthquake of M8.0 in 1605, Hoei Earthquake ofM8.4 in 1707, Ansei-Tokai Earthquake ofM8.4 in 1854, Ansei-Nankai Earthquake of M8.4 in 1854, Showa-Tonankai Earthquake of M7.9 in 1944 and Showa-Nankai Earthquake of M8.0 in 1946.

Japanese economy is also developed well in coastal areas. Since Japan has few natural resources and depends on foreign imports, industries are well developed especially around ports. Metropolises are extended in large port areas facing the Pacific Ocean. Thus, social and economic development has progressed in coastal areas, especially port areas, which are vulnerable against tsunami and storm surge.

Fig. 2.2: Past earthquakes and tsunami in Japan (form Ports and Haubour Bureau, MLIT, Japan) Along the Japan Trench in the northeastern sea off the main island of Japan, in which the Pacific Plate plunges below the North American Plate, many tsunamis have also occurred. The Meiji-Sanriku Earthquake of M8.5 in 1896 induced a big tsunami, by which over 20,000 persons were killed, approximately 9,000 houses were washed away, and over 6,000 vessels were destroyed. The highest run-up height of the tsunami of 38.2 m was recorded at Ayasato, Iwate Prefecture. Since this earthquake is one of those called Slow Earthquake or Tsunami Earthquake, which release slowly the earthquake energy with a little shaking but big tsunami, almost people were not aware of a possible tsunami after the little earthquake. In the Sea of Japan, two big earthquake tsunamis were recorded most recently. The Nihonkai Chubu Earthquake of M7.7 in 1983 occurred about 100 km west of the coast of Noshiro in Akita Prefecture, and it generated the tsunami which killed 100 persons along coast of the Sea of Japan: 41 construction workers in ports and harbors,18 sport fishing persons, 6 fishermen on boats overturned, and 13 children who came to a beach for school excursion, 1 visiting foreigner, 3 working farmers and others. The run-up height was larger from the northern part of Akita Prefecture to the north shore of the Oga peninsula. The highest tsunami run-up was 14 m at Mine village, Aomori Prefecture. The earliest tsunami arrival time was 7 minutes after the earthquake in Fukaura Port, Akita Prefecture. It was a slight receding tsunami. The retreating tsunamis at first were also measured at the ports of Esashi, Matsumae and Yoshioka in Hokkaido Prefecture, and Noshiro in

Akita Prefecture. In the others, the first was a flooding tsunami. The measured largest sea level rise including tide was 2.08 m at the tide station in Noshiro Port, and tsunami height was 1.94 m. Even in the east coast of Korea, the high sea level rise of 1.23 m was measured, including 0.98 m of the tsunami height. The typical wave period of the tsunami was about 10 minutes in a lot of ports and harbors. However, predominant periods were longer in some ports, because of harbor resonance. Another earthquake in the Sea of Japan is the Hokkaido Nansei-oki Earthquake of M7.8 in 1993. The earthquake also induced the tsunami which caused devastating damage especially in Okushiri Island, Hokkaido Prefecture. The number of victims by the tsunami and earthquake was totally 230 persons. About 80% of the victims in Okushiri Island were by the tsunami: 172 dead and 26 missing people. The tsunami climbed a steep hill surface up to 31.7 m at the Monai area in Okushiri Island. The high tsunami runup is affected by bathymetry and topography: Locally very shallow water area consisting of a pocket beach of about 250 m long and two tiny islands in front of the hill increased tsunami height, and the hill surface scooped like the V character also helps the tsunami to converge tsunami flow, resulting in the high runup. Part of the Aonae area on a southern promontory of Okushiri Island was hit by the tsunami on over 10 m, resulting in destruction of all of 77 houses on low-lying flatten area. Large numbers of death toll in Okushiri Island depended on arrival time of the tsunami as well as height of the tsunami. Since the epicenter was located in the north-northeast about 50 km off Okushiri Island, the tsunami arrived at Okushiri Island 3 5 minutes immediately after the earthquake. The Aonae area was hit twice by the tsunami. The first tsunami came from west approximately 5 minutes after the earthquake, which is the tsunami propagating from the tsunami source. The second tsunami struck the area from northeast a few minutes after the first attack, which is the tsunami diffracted and refracted by the island. The Yaeyama Earthquake Tsunami occurred in 1771 near Yaeyama Island in Okinawa, most south part of Japan. The magnitude of earthquake was 7.4 and the earthquake brought no victims directly. However, the induced tsunami whose run-up height was over 30 m in Ishigaki Island killed totally about 12,000 people. According to ancient documents, the highest run-up by this tsunami was 85.4 m in Ishigaki Island.

Distant tsunami (Teletsunami) also caused damage. In 1960 the tsunami induced by the Chilean Great Earthquake of M 9.5 off the coast of Chile propagated through the Pacific Ocean and hit coasts of Japan: not only the coasts facing to the Pacific Ocean but the coasts along the Sea of Japan, which is shaded by Japan islands. For example, in the Sanriku coast, northern part of the main island of Japan, the tsunami arrival time was 22 hours after the earthquake and runup height was over 6m. Total victims by this tsunami were 142 people.

Photo 2.2: 1960 Chilean Tsunami striking in Ofunato (from HP of Iwate Prefecture, http://www.pref.iwate.jp/~hp0606/harbor/harborinfo/oohunato/tunami.html)

2.2.4 Various Damages by Tsunami

Tsunamis have caused various types of damage as well as a number of victims and wide inundation on land (Photos 2.1 and 2.2): destruction of houses (Photo 2.3), damage of transportation facilities such as ports and harbors (Photo 2.4), damage of aquaculture facilities, erosion and deposition in coastal areas, damage of vessels and cars (Photos 2.5, 2.6 and 2.7), secondary damage by debris and drifted vessels and timbers (Photos 2.8 and 2.9), fire spreading (Photo 2.10) and other .

Photo 2.3: Destruction in the Taro area, Miyako City Iwate Prefecture by the 1946 Sanriku Earthquake Tsunami (From the web page of information on tsunami disaster management in Taro, http://211.120.127.11/Bousai/tsunami/index.html)

Photo 2.1: Tsunami inundation in Kiritappu, Hokkaido, Japan by the 1960 Chilean Tsunami (from presentation of the Ports and Harbours Bureau, Ministry of Land, Infrastructure, Transport and Tourism, Japan)

Photo 2.4: Damage of breakwater in Okushiri Port by the 1993 Hokkaido Nansei-oki Earthquake Tsunami (Tanimoto et al,. 1993)

Photo 2.8: Various debris and vessels in Sizugawa Town, Akita Prefecture by the 1960 Chilean Tsunami (from the web page of the Tohoku Regional Bureau, Ministry of Land Infrastructure, Transport and Tourism, Japan, http://www.thr.mlit.go.jp/Bumon/B00045/road/sesaku/jishin/jishin2.h

Photo 2.5: Inundated cars in Ohtsu Fishery Port, Town of Toyokoro, Hokkaido Prefecture, by the 2003 Off Tokachi Earthquake Tsunami (Photo courtesy of Tokachi Port and Harbor Office) tml)

Photo 2.9: Fishing boat drifted in the Aonae area by the 1993

Hokkaido Nansei-oki Earthquake Tsunami (Tanimoto et al., 1993)

Photo 2.6: Fishing boat lifted on the wharf beside oil tanks in Tokachi Port by the 2003 Off Tokachi Earthquake Tsunami (Photo courtesy of Tokachi Port and Harbor Office, Hokkaido Bureau, Ministry of Land Infrastructure, Transport and Tourism, Japan)

Photo 2.10: Aonae Town devastated by the flooding of the 1993 Hokkaido Nansei-oki Earthquake Tsunami and tsunami-induced fire spreading (Tanimoto et al., 1993)

2.2.5 Tsunami Damage and Preparedness in Ports

(1) Susaki Port The Susaki Port is located nearly in the center of Tosa Bay, south of the Shikoku Island. It is a good natural port opened in a ria coast. Such a geophysical feature provides especially weakness against the tsunami coming from an open sea. The port has suffered damage

Photo 2.7: Salvaging work of fishing boat sunk in Ohtsu Fishery Port by the 2003 Off Tokachi Earthquake Tsunami

by tsunami repeatedly. The Nankai Earthquake Tsunami in 1946 and the Chilean Tsunami in 1960 triggered serious damage.

Chilean Tsunami in 1960 The tsunami caused severe damages in the Oma area and the downtown of Susaki City. In the Oma area, a lot of houses were broken by timbers that flowed out from timber yards on the land since some parts of the embankment were breached by the tsunami attack and the seawater flooded the timber yards and the vicinities. The downtown of Susaki City was flooded by the tsunami that ran up a river named Horikawa and then a number of houses received serious damage. Photo 2.11: Part of tsunami breakwater in Susaki Port, The

breakwat5er in a circle is part of the breakwater constructed already in 2001

Preparedness against tsunamis of the port

Learning from historical tsunami disasters, Susaki will be hit by tsunamis in the future. In order to mitigate the possible tsunami disasters, a tsunami breakwater (Photo 2.2.11) and seawalls have been constructed. The target tsunami for disaster management is Showa Nankai Earthquake Tsunami in 1946, which caused severe damages and whose accurate records were remained. The tsunami breakwater has been constructed since 1992 instead of construction of high seawalls along long coast. The breakwater consists of three parts whose lengths are 700, 200 and 480 meters. However tsunami disaster prevention accomplishes with the combination of the breakwater and seawalls.

Photo 2.12: Large display of disaster-related information in Susaki City

Not only the above-mentioned structural countermeasures the city government has prepared various countermeasures. All the citizens now have tsunami hazard maps which indicate inundation areas and evacuation routes and places and can join tsunami-lecture meetings and the evacuation drills. People can see tsunami evacuation signs in the streets and more recently, for dissemination of tsunami information, an electrical bulletin board is placed in the center of Susaki City (Photo 2.12). In the board, meteorological and maritime information is displayed as well as real-time information of the tsunami measured at the Susaki Port.

(2) Kamaishi Port Kamaishi City is situated in the south-eastern section of Iwate prefecture, in the center of the Sanriku coastline which is a ria coast and designated as the Rikuchu National Park. .Since it situated in part of the ria coast which makes good harbors, the Kamaishi Port has suffered a number of tsunami disasters in the same way as the Susaki Port. The 1896 Meiji Sanriku Earthquake Tsunami, 1933 Showa Sanriku Earthquake Tsunami and1960 Chilean Tsunami caused serious disasters in Kamaishi. Overview of the disaster in the port area The Meiji Sanriku Earthquake Tsunami in 1896, whose epicenter located 200 kilometers off Kamaishi, caused the following damages: - 4,985 death or missing persons out of the population of 6,529 in Kamaishi Town at that time,

- 1,046 damaged houses, - 151 inundated houses, - 137 damaged vessels. The Showa Sanriku Earthquake Tsunami in 1933 caused the following damages: - 403 death or missing persons, - 1,046 damaged houses, - 151 inundated houses, - 137 damaged vessels. The Chilean Tsunami in 1960 caused the following damages: - 142 death or missing persons, - 1,046 damaged houses, - 151 inundated house, - 137 damaged vessels. Preparedness against tsunamis of the port In Kamaishi port, the tsunami breakwater was constructed in the mouth of Kamaishi Bay, whose water depth is 63 m. It is the breakwater constructed in deepest water in the world.

NE

WS Opening section

of breakwater

(Outside of breakwater)

(Outside of breakwater)North breakwater

990 mOpening section

300 mSouth breakwater

670 m

Caissons

Mound

Plain view

Cross-section view

-19 m

Fig. 2.3: Outline of tsunami breakwater in Kamaishi Port (3)Okushiri Port Photo 2.13 is a photo of the Aonae district of Okushiri Island just after the Hokkaido Nanseioki Earthquake TsunamiOkushiri Tsunami. As already mentioned, the tsunami attacked the Okushiri Island, especially the Cape Aonae District including Okushiri Port. After the disaster, construction work was implemented to establish a total disaster prevention system for Okushiri Island. Figure 2.4 shows a map of land use planning, where houses in the most severely damaged areas were to be moved to high land areas and some

land reclamation would be done to create higher land areas. Photo 2.15 shows the seawalls in front of the reclaimed lands and an artificial high ground in the fishery port where fishermen can work daily on the first floor and use the second floor for evacuation.

Photo 2.13: Aonae district and fishery port, Hokkaido, JAPAN (More than 10 m tsunami washed the hoses in the area into the fisher port)

New Town

Park

ReclamationSeawall

Figure 2.4: Land use planning of Aonae districtt)

Artificial High Ground11m seawall

6m Seawall

Fishery Port

Photo 2.14: Tsunami Refuge Terrace at Aonae fishery port, Hokkaido, JAPAN (Refugees run up the terrace, and then evacuate mountain area through the overpass deck when tsunami warning alert is announced)

(3) Other ports Ofunato Port The Chilean Tsunami in 1960 struck Ofunato City which is a city in Sanriku coast, northern part of main island of Japan. The water surface disturbance was caused at 3:10 AM such as storm surge firstly, and then the sea surface was retreated from 3:13 AM, which reached the lowest level of 3.8 m. Around 4:40 AM 90 minutes later, the flooding tsunami came gently but caused serious disaster in Ofunato City. The tsunami inundated the rice field 2 km away from the coast. Especially the inner bay coast which had less damage by the historical Sanriku tsunamis before the Chilean Tsunami suffered hardly damage. On the other hand, the bay mouth area had less damage by the Chilean Tsunami gave less damage in the bay mouth area which had big damage by the Sanriku tsunamis. The difference of damaged areas depends on the resonance of tsunami by the bay. In the sea surface, the cultivation facilities for oysters, laver, and etc. were flushed completely away. Noshiro Port Noshiro port was struck by the 1983 Sea of Japan Tsunami. The tsunami arrived at the Noshiro Port around 20 minutes after the earthquake. The tsunami was deformed to a bore with soliton fission (undulation bore) on the sea bed with mild slope angle less than 1/200, which is continue to 30 km offshore from the shoreline. The run-up height reached 5 6 meters there. The tsunami attacked also the construction site of a seawall for a power plant yard in the port. Since it was during the day, a lot of construction workers were sacrificed on the site and vessels. Parts of the seawall were also damaged. Some caissons were moved and dropped down from the foundation works. The damaged areas of the seawall were under construction of wave-dissipation works and back-fill works. In the parts where the back-fill works were completed, there is less damage. Akita Port The 1983 Sea of Japan Tsunami cluttered timbers on the sea surface in the port and on the yards beside the old river of Omonogawa. The tsunami run off the 15,000 timbers out of a total of 28,000 approximately. Fukaura Port The Fukaura Port was attacked earliest by the 1983 Sea of Japan Tsunami. It was 7 minutes after the quake. The

tsunami run-up height was more than 3 meters. The tsunami overtopped low-crested breakwater whose height was CDL+2.0 meters, and the strong outflow was generated at the opening section of the breakwater in the phase of the retreating tsunami. This provided less difference of the tsunami run-up heights between the inside and outside of the port

2.3 U.S. (2) Risk to the East Coast The East Coast of the United States has experienced few tsunamis as there are few tsunamigenic faults in the North Atlantic. Additionally, the wide continental shelf off the East Coast should moderate distant tsunami effects (Lander and Lockridge 1989). Damage to U.S. ports has been almost exclusively to those in the Pacific States.

2.3.1 Tsunamis and Their Damage in the Ports of the

United States

(1) Tsunami history and mitigation steps The United States has experienced over 80 significant tsunamis in its 230 year history resulting in over 370 deaths and over $180 million in damage to ports, property, and vessels. The more recent major tsunamis spurred the U.S. to take steps to mitigate the risk. The 1946 Alaskan tsunami, which took 5 lives in Alaska and 173 lives in Hawaii, prompted the U.S. Government to establish the Pacific Tsunami Warning Center in Hawaii. The 1960 Chilean tsunami, which claimed 1,000 lives in Chile, 199 in Japan, and 61 in Hawaii, and the 1964 Alaskan tsunami, which claimed 117 lives in Alaska, 11 in California, and 4 in Oregon resulted in the U.S. establishing the International Tsunami Information Center in Hawaii, the Joint Tsunami Research Effort, and the Alaska Tsunami Warning Center in Palmer, Alaska (Bernard 2005).

(3) Risk to the West Coast, Alaska, and Hawaii The potential for tsunami generation along the West Coast of the U.S. exists along the Alaskan-Aleutian Subduction Zone, the Cascadia Subduction Zone (CSZ), the south coast of the island of Hawaii, and along the Palos Verdes, Santa Cruz Island, and Santa Rosa Island faults in Southern California. Three of the four tsunamis which claimed lives in the U.S. in the last 100 years were generated along the Alaskan-Aleutian Subduction zone. The waters off the coast of Alaska are the most seismically active in the Pacific, and produced the strongest recorded earthquake of magnitude 9.2 in 1964. According to the USGS, the Cascadia Subduction Zone (CSZ) has a 10% to 14% chance of producing a large magnitude earthquake and associated large tsunami in the next 50 years (Tsunami Preparedness Act, 2005). The local tsunami hazard in the Pacific Northwest wasnt fully realized until the late 1980s. The CSZ is now recognized as a potential source of megathrust events, which can result in an 8.0 to 9.0 magnitude earthquake, and a major Pacific-wide tsunami similar to the Indian Ocean tsunami, see Fig. 2.5. These conclusions were corroborated by evidence found of previous tsunamis along the Oregon-Washington coast (Geist 2005).

In 1992, an earthquake of magnitude 7.2 off the Northern California coast generated a small tsunami, but propagated large concerns in coastal residents. This tsunami and a false Pacific-wide tsunami warning following the 1994 Kuril Island earthquake prompted Congress create the a workgroup of federal agencies and Pacific Coast States. This led to the establishment of the National Tsunami Hazard Mitigation Program (NTHMP) in 1996, a collaborative effort of NOAA, the U.S. Geological Society (USGS), the Federal Emergency Management Agency (FEMA), and the five coastal states, Alaska, California, Hawaii, Oregon, and Washington. Over the past ten years, the NTHMP has focused on 1) Improving detection and warning systems, including developing a seismic network, deployment of tsunami detection buoys (DART), and improved state/federal coordination and support for tsunami warnings; 2) Mitigation, which includes developing state/local tsunami hazard mitigation plans; and 3) Tsunami Hazard Assessments, i.e., producing accurate and useful inundation maps (Gonzales, et al. 2005). The NTHMP has made notable progress in all three areas. The two warning centers now have information from a global seismic network. The DART system buoys have been in place since 2001. Tsunami inundation maps have been developed for most of the at-risk communities on the West Coast.

Fig. 2.5: Comparison of the 2004 Sumatra rupture and the 1700s Cascadia Subduction Zone rupture. The bar on right is a 700-mile scale (Source: California Seismic Safety Commission (CSSC), Publication 05-03) The likelihood of a local tsunami in Southern California is believed to be similar to that of the CSZ event (California OES). Researchers in Southern California believe that there is a credible tsunami threat from sub-marine landslides in the Santa Barbara Channel. However, Cascadia Subduction Zone poses the greatest threat of producing a large tsunami that will hit California (CSSC 05-03). The tsunami threat to Hawaii is greater from the distant tsunami than the local Kona Fault, as is impacted by tsunamis generated from any of the Pacific Rim Faults. The at-risk communities and population from the local tsunami hazard on the West coast was summarized by NOAA in 2005 and is presented in Table 2.2. Table 2.2: At risk populations in Pacific States, 2000 Census (Source: Gonzalez, et al. 2005)

State Communities At-risk Population

Alaska 147 122,150 California 58 1,948,813Hawaii 63 383,280 Oregon 31 95,094 Washington 104 899,236

Total 500 3,447,573 By looking at the effects of tsunamis on the major ports along the Pacific States, a better idea can be gained of the expected damage from tsunamis. A comprehensive summary of damage from tsunamis in the U.S. can be found in the U.S. Department of Commerce publications listed in the references. The information below is mainly taken from these publications.

2.3.2 California

(1) San Diego The March 9, 1957 Alaskan-Aleutian Islands magnitude 8.3 earthquake generated a tsunami which resulted in a 1 meter wall of water entering San Diego bay. Currents of 46 km/hr were reported, and several ships broke lose from their moorings. The May 22, 1960, Chilean magnitude 8.6 earthquake

generated a Pacific wide tsunami with a measured wave of 0.7 meters in San Diego, where it destroyed 80 meters of dock, 8 small boat slips, and broke several ships and barges free of their moorings. Currents were estimated to have reached 40 km/hr in the entrance to the channel (Lander and Lockridge 1989). The March 28, 1964 Alaskan Prince William Sound magnitude 9.2 earthquake produced a Pacific wide tsunami that caused the water to rise 2 meters in the entrance channel to Mission Bay. Several moorings were broken from the strong currents (Lander and Lockridge 1989). (2) Los Angeles/Long Beach The ports of Los Angeles and Long Beach are at perhaps the greatest exposure to catastrophic losses, as they do not have any significant natural or man made protection from a tsunami. The Inner Harbor is on average 3 meters above mean high water level, and a 5 meter or larger tsunami could inundate much of the 7500-acre port area. A two month shutdown of the LA/LB ports could cost $60 billion. This does not include the direct damage by the tsunami to vessels and port infrastructure (CSSC 05-03). The 1960, Chilean tsunami caused $1 million in damage to the port of Los Angeles as wave heights were estimated to be near 2 meters and currents estimated to be 8 knots in the harbor. Over 800 vessels broke their moorings, mostly small craft; forty were sunk and 200 damaged (Lander and Lockridge 1989). The 1964 tsunami from the Alaskan earthquake produced two 2 meter surges of water in Los Angles harbor. Seventy five to a hundred boats were broke free from their moorings mostly on the Terminal Island side of the Cerritos Channel. Three small boats were sunk. Damage was done to a pier from a tanker which was mooring at the time the first surge hit (Lander and Lockridge, 1989). (3) San Francisco The 1960, Chilean tsunami caused the waters in San Francisco bay to rise 0.5 meter near the Golden Gate. Minor damage at various marinas was reported and ferry services were temporarily disrupted due to large currents. The 1964 tsunami from the Alaskan Prince William

Sound earthquake produced a wave height of 1.1 meters near the entrance to San Francisco Bay. Strong currents damaged marinas and sank several boats in San Rafael and Sausalito where damage totaled $1 million (Lander and Lockridge, 1989). (4) Crescent City Crescent City, California is not a major port, but has experienced the most tsunami damage of any port on the West Coast. The surrounding bathymetry tends to focus tsunami wave energy toward this port. The 1960 Chilean tsunami had a run-up of 4 meters at Crescent City and resulted in 2 vessels being sunk and the city dock area being flooded. The $11 million in damage to Crescent City from the tsunami from the 1964 Alaskan earthquake was the greatest ever from a tsunami to a port on the West Coast. Damage exceeded $11 million and 11 people were killed as four tsunami waves swept into the harbor over a period of four hours. The third wave was the largest at 6.3 meters and caught many people off guard as they returned to the damaged waterfront after the second wave. Twenty one commercial fishing vessels were lost. A Coast Guard cutter, a tug boat, and a few fishing boats were able to make it out of the harbor and into deep water to ride out the waves. The waterfront, piers, and 30 blocks of the city were devastated (Lander, et al. 1993). The 2006 Kuril Islands Earthquake created surges that caused an estimated $700,000-$1,000,000 in losses to the small boat basin at Citizens Dock, destroying two floating docks, damaging a third and causing minor damages to several boats (Kelly, et al. 2006).

2.3.3 Oregon

(1) Portland There has been no reported tsunami damage to this major port as it is located over 100 miles up the Columbia River. Oregons coastal ports have been damaged by past tsunamis with damage mainly to small vessels and their moorings.

2.3.4 Washington

(1) Seattle, Tacoma, and Olympia There has been no reported tsunami damage to the major ports in Washington. The 1964, Alaskan

tsunami had a recorded amplitude of 0.4 feet at Seattle. Geologists have recently determined that the Seattle Fault which runs east-west under the Port of Seattle and Elliot bay generated and earthquake and a local tsunami 1000 years ago and could again in the future. Numerical modeling of the worst case credible earthquake in the Seattle Fault estimates tsunami run-up heights of 6 meters in the Port of Seattle, which would be devastating.

2.3.5 Alaska

(1) Juneau The port of Juneau recorded tsunami heights of 1.1 meters from the 1964 Alaskan Prince William Sound earthquake, however there was little to no damage at the port. It is possible but unlikely that a distant tsunami could cause major damage at the port of Juneau (Lander, et al., 1993). (2) Anchorage There has been little to no damage at the Port of Anchorage from tsunamis. The location of Anchorage at the end of Cook Inlet and the shallow depth of the inlet has limited the effects of distant tsunamis on this port. (3) Valdez The town of Valdez was located on a delta of silty sand and gravel. When the 1964 earthquake occurred in Prince William Sound earthquake occurred, a section of the waterfront with the dock area and part of the town, 1220m long and 183m wide slid into the bay (Photo 2.15). This devastating slump then created a local 9-12 meter tsunami which hit the town 2-3 minutes after the earthquake. A freight vessel at the Valdez dock unloading cargo was raised 9 meters and heeled over 50 degrees bay the wave, which then went on to demolish the remainder of the waterfront facilities, the fishing fleet, and penetrate 2 blocks into the city. A fire then broke out at tank farm near the shore. The freight vessel was able to get underway and maneuver into deeper water.

Photo 2.15: Port of Valdez and waterfront destroyed from March 1964 tsunami (Source: National Geophysical Data Center)

Photo 2.16: Damage at Seward following tsunami of March, 1964 (Source: National Geophysical Data Center) (4) Seward The 1964, Alaskan earthquake cased a similar landslide at the Port of Seward, as a 1,070 meter by 91 meter section of the waterfront slide into Resurrection Bay. Fire broke out along the waterfront as oil spread from ruptured tanks at an affected tank farm. Waves from the landslide did some damage, but a larger wave from the main earthquake reached Seward 20 minutes later. This wave measured 9 meters and inundated several blocks into Seward (Lander and Lockridge, 1989). photo 2.16 shows some of the damage with fishing vessel carried onshore and a tank truck destroyed in the foreground. (5) Kodiak 1964 Alaskan earthquake produced tsunami waves over nine meters at Kodiak which caused nineteen deaths and over $31 million in damage. All of the floating docks behind the breakwaters were carried away and all docks and wharves, except the City Dock, were destroyed. Most of the fishing fleet moored in the harbor was destroyed, as the wall of water carried 90 metric ton vessels three blocks into the city. Fifteen of the nineteen

fatalities in Kodiak were among fishermen trying to save their boats after the first smaller wave hit the harbor (Lander and Lockridge 1989). The Kodiak Naval Station sustained $10 million in damage from the tsunami, including complete destruction of the cargo dock and heavy damage to roads and bridges.

2.3.6 Hawaii

(1) Hilo In 1923 a six meter tsunami struck Hilo from earthquakes in the Gulf of Kronotski, Kamchatka. The railroad line was washed out, wharves were damaged and fishing vessels were washed ashore. On April 1, 1946, the port of Hilo on the island of Hawaii was devastated by a tsunami generated from a 7.3 M earthquake along the Aleutian Islands in Alaska. The waves hit unexpectedly and had people running for their lives in downtown Hilo. The waterfront was destroyed by waves over eight meters high (Lander and Lockridge, 1989). The man in Photo 2.17, who cut a mooring line freeing a freighter at Pier 1, was taken by the wave and became one of the ninety six casualties in Hilo. The vessel was able to make it safely out to sea. Many smaller vessels were washed up to 400 meters inland. Photo 2.18 shows the damage to Pier 2.

Photo 2.17: Tsunami of 1946 breaking over Pier 1 in Hilo, Hawaii. The man in the photograph cut a mooring line on a freighter before becoming one of the 156 casualties in Hawaii (Source: Pacific Tsunami Museum website.)

Photo 2.18: Damage to Pier 2 in Hilo following 1946 tsunami (Source: Pacific Tsunami Museum website.) In 1952, an earthquake on Kamchatka generated a tsunami which struck Hawaii. The highest measured wave heights were near Hilo at 3.5 meters. A boathouse was destroyed as a 2.4 meter wave washed over a wharf in Hilo. Coast Guard navigation buoys were broken loose from their moorings (Lander and Lockridge, 1989). In 1957, an earthquake of Adak Island in Alaska produced a tsunami of 1 meter in Hilo and caused $300,000 in damage to cargo at Pier 1. Fishing boats were carried inland. Buildings along the waterfront were badly damaged. A marine dry dock was also destroyed. The 1960 Chilean earthquake generated a Pacific wide tsunami which struck the Hawaiian Islands. Hilo, the worst hit of the ports in Hawaii, had $23.5 million in damage and all of the 61 fatalities. Around Hawaii the waves acted like a slowly rising tide, except in Hilo, where the third wave came in as a bore and resulted in a run-up of 6 meters. In half of the 600-acre area, inundated inland of Hilo harbor, there was total destruction. Only steel framed and reinforced concrete buildings, and a few sheltered by these buildings, remained standing in this area. Frame buildings were crushed or floated away. Photo 2.19 shows some of the damage to Hilo. The 1964 Alaskan tsunami, while devastating ports in Alaska and causing damage along the West Coast of the U.S., only caused minor damage in Hawaii. Again Hilo received the highest measured wave heights of 3 meters. Some waterfront buildings were flooded and the approach to a bridge was damaged. (2) Honolulu

The 1952, tsunami generated from an earthquake on Kamchatka forced a cement barge loose from its moorings in Honolulu harbor and rammed it into a moored freight vessel. The 1946 and 1960 tsunamis which were devastating to Hilo only caused minor damage in Honolulu harbor.

Photo 2.19: Damage to the Waiakea area of Hilo from the 1960 Chilean tsunami (Source: Pacific Tsunami Museum)

2.3.7 Summary

Damage from tsunamis varies greatly from the source event, tides, and location of the ports. In naturally protected ports, such as San Diego, San Francisco, and Honolulu damage is mostly from strong currents. Exposed ports and those with bathymetry which tends to focus tsunami energy, such as Hilo and Crescent City, received more catastrophic damage from the impact of tsunami waves and bores.

2.3.8 References

Bernard, E. N.(2005): The U.S. National Tsunami Hazard Mitigation Program--A successful state-federal partnership. IN Bernard, E. N., editor, Developing tsunami-resilient communities--The National Tsunami Hazard Mitigation Program: Springer, 5-24.

Geist, Eric L. (2005): Local tsunami hazards in the Pacific northwest from Cascadia Subduction Zone Earthquakes: U.S. Geological Survey Professional Paper 1661-B. [accessed Dec. 12, 2005 at http://pubs.usgs.gov/pp/pp1661b/]

Gonzalez, F. I., V.V. Titov, H. O. Mofjeld, A.J> Venturato, R. S. Simmons, R. Hansen, R. Combellick, R. K. Eisner, D. Hoirup, B. Yanagi, S. Young, M. Darienzo, G. Priest, G. Crawford, and T. Walsh (2005): Progress in NTHMP

Hazard Assessment,. Natural Hazards, 35,

Kelly, A

American

Lander,

ation, Department of Commerce,

Lander,

ation, Department of Commerce,

Pacific ssed Dec. 21, 2006

89-110. ., L.A. Dengler, B. Uslu, A. Barberopoulou, S.C. Yim, and K.J. Bergen (2006): Recent tsunami highlights need for awareness of tsunami duration, EOS Transactions,Geophysical Union, 87, 566-567. J. F. and P.A. Lockridge (1989): United States Tsunamis (including United States Possessions) 1690-1988. National Geophysical Data Center, National Oceanic and Atmospheric AdministrBoulder. J. F., P.A. Lockridge and M.J. Kozuch (1993): Tsunamis affecting the West Coast of the United States 1806-1992. National Geophysical Data Center, National Oceanic and Atmospheric AdministrBoulder. Tsunami Museum Inc. [acceat http://www.tsunami.org]

f California Governors Office of Emergency Services (California OES) (2004): Local planning guidance on tsunami response: A supplement to the eme

State o

rgency planning guidance

State of

endations on tsunami

United

., 1st session. Washington: GPO, Apr. 19, 2005.

for local government. California Seismic Safety Commission (CSSC) (2005): The tsunami threat to California: findings and recommhazards and risks, pub.

States Senate (2005): Tsunami Preparedness Act, Report of the Committee on Commerce, Science, and Transportation on S. 50. 109th Cong

2.4 MEXICO

2.4.1 Introduction The subduction of the Cocos Plate along the Pacific Coast of Mexico makes this region one of the most active seismic zones in the Western Hemisphere. During the last century Mexico has had approximately 40 strong earthquakes. At least 14 of the earthquakes in the last three centuries were the source of locally destructive tsunamis with waves from two to eleven meters high. Aside from the local tsunamis, nondestructive tsunamis of distant origin have also arrived to the Mexican Pacific Ocean coast. Two hazardous zones can be clearly differentiated in the Pacific Coast of Mexico. All of the local source tsunamis were generated in the southern part, along the Middle America Trench, where the Cocos Plate subsides underneath the North American Plate (Fig. 2.5); some of them had very destructive local effects. Their wave heights and coastal effects gradually decreased from the source to the north and south along the coastline, becoming even smaller elsewhere across the Pacific Ocean. The September 19, 1985, and th October 9, 1995 tsunamis are the most recent examples of this (Pararas-Carayannis, 1985; Farreras and Snchez, 1987; Ortiz et at., 2000). North of the Rivera fracture, the Pacific Plate slides northward along the Gulf of California strike-slip fault with respect to the North American Plate. As a result of this, Baja California and the Gulf of California are not a source area of local tsunamis, but only a recipient of those from distant source (Fig. 2.6). Maximum wave height for the nine recorded local events of the last 39 years at all available tidal gauges are, with a few exceptions, smaller than 2 meters (Snchez and Farreras, 1987). This short term information may be misleading, leading to the erroneous conclusion that local tsunamis are not a real threat, while historical information from the last three centuries indicates just the opposite. Tectonic source parameters of six Mexican tsunamigenic earthquakes compared with those of the large 1960 Chilean and 1964 Alaska earthquakes show much smaller (1% to 2%) seismic moments; a shorter, narrower, and deeper submersion of the aftershock areas; and smaller vertical uplifts (Snchez and Farreras,

1988). This seems to indicate that major Mexican earthquakes do not have the potential and efficiency to generate and spread enough energy all across the Pacific Ocean through large, destructive generated tsunamis. Historical information, at least until now, confirms this (After Snchez and Farreras, 1993). Snchez and Farreras prepared the Catalog of Tsunamis on the Western Coast of Mexico, a compilation of information pertaining only to tsunamis of seismic origin observed and/or recorded in the Pacific Ocean coast of Mexico from 1732 to 1993. Tsunamis observed on the East coast of Mexico (Gulf of Mexico and the Caribbean) are not considered. The earliest observation date of a tsunami is February 25, 1732, while the earliest record is dated November 4, 1952. A questionable tsunami occurred in 1537 but the event is poorly documented.

Fig. 2.6: Seismotectonic setting and predominance of Tsunami along of the Pacific Ocean coast of Mexico (After Snchez and Farreras, 1993) Recorded or observed remote source tsunamis had very seldom reached more than 2 meters run-up height and posed no significant threat to the coastal communities. Since the operation of the tidal gauge network dates back no more than 40 years, and most of the Pacific Coast of Mexico, with the exception of a few places like Acapulco, remained uninhabited until the 1800's, information on the arrival of this type of tsunamis during ancient times is limited and unreliable. Furthermore, the native population either kept no written records, or the records were destroyed during the Spanish occupation. The information in the archives of Seville for this period is neither accessible for a search,

2.4.3 Nationwide Network of Oceanographical And Meteorological Stations

nor do they have the required financial support to perform a search. Consequently it was only possible to document and give a very brief description of four remote source tsunami arrivals from ancient times for mentioned catalog. All four of them came from South America. There is no doubt that other Pacific-wide macro-tsunamis might have arrived unnoticed.

As part of the process to integrate a proper data set of information on oceanographic and meteorological data, which is framed between the strategic activities of the Program for the Development of Infrastructure Maritime Port Authority (PRODIMAP in Spanish) and the Program for Development of Littorals (PRODELI in Spanish). Both programs undertaken by the General Direction of Ports of the Ministry of Communications and Transport, and within which they take the necessary steps to provide such information to be essential for the various works related to the better use of port infrastructure and the Mexican coastlines, the General Direction of Ports and the Mexican Institute of Transport have joined a program to develop the Nationwide Network of Oceanographic and Meteorological Stations (RENEOM in Spanish).

2.4.2 Tide Gauge Network

The tidal gauge network first started operation in 1952. A total of 21 different tsunamis events were recorded by the network from 1952 to 1985 (Fig. 2.6), (about two tsunamis recorded every three years). However, since September 1985, only one local large tsunami (October 9, 1995) was recorded in the western coast of Mexico. Nine of the recorded tsunamis were from local sources, and twelve came from abroad: two each from the Aleutian Islands, U.S.S.R., and Peru, and one each from Alaska, Hawaii, Japan, Chile, Colombia and New Zealand. From the 69 records mentioned in Fig. 2.7, two of them were not available to the authors of this catalog for publication: La Paz Nov 4 1952 and Mazatlan May 22 1960. Figure 2.7 also shows the number of events recorded by each of the gauge stations (Acapulco has the maximum: 19).

The program envisages the installation of equipment for the measurement of waves, sea levels, meteorological parameters and tsunamis along both, the Pacific and Atlantic coasts of Mexico. The equipment will operate in a systematic manner to provide information for multiple purposes. The program for the establishment of the National Network of Oceanographic and Meteorological Stations (RENEOM), has been planned in three stages: the first already developed in 2006 (short term), the second to take place in 2007 (medium term) and the third stage to take place in 2008 (long-term).

The design of the monitoring system for tsunamis in real-time was made during the years 2002-2004 under the research project "Coastal Response to Local and Regional Tsunamis, an internal project of the Department of Physical Oceanography at CICESE, Mexico. The system for the real-time high-frequency sea-level observations consists of a pressure sensor that can be installed in coastal waters. The instrument operates at frequency of 16 Hz with resolution of 0.002% of the depth, which can detect variations of 2 mm of sea level when the instrument is installed at a depth of 100 meters. The pressure sensor does not operate with batteries and has no internal memory. The electric current is supplied through a robust cable of 4 wires, which in turn enables

Fig. 2.7: Date, gauge location, source type, and number of tsunami records in existence, in the Western coast of Mexico (After Snchez and Farreras, 1993) In Tables 2.3 and 2.4 are presented the chronologies summaries of local and distant tsunamis recorded or observed along the Mexican Pacific coast.

digital communication with the instrument via an RS232 serial port connected to a computer (PC). The length of the cable can be up to 1,000 m. The computer (laptop or desktop) sends the data via the Internet to one or several servers responsible for maintaining available the sea-level data on a web page in real time. This observation system has been in operation since September 2004 in the port of El Sauzal, Baja California (see http://observatorio.cicese..mx). Fig. 2.8, illustrates the tsunami observing system.

2.4.4 REFERENCES Ortiz M., V. Kostoglodov, S.K. Singh and J. Pacheco

(2000): New constraints on the uplift of October 9, 1995 Jalisco-Colima earthquake (Mw 8) based on the analysis of tsunami records at Manzanillo and Navidad, Mexico. Geof. Int., 39(4), 349-357.

Sanchez. D. A .J. and S.S.F. Farrera (1993): Catalog of Tsunamis on the Western Coast of Mexico, World Data Center A for Solid Earth Geophysics Publication SE-50, National Geophysical Data Center, NOAA, In Spanish and English.

6 real-time tsunami observing systems will be installed in the following ports during the year 2006: Mazatlan, Puerto Vallarta, Acapulco, Salina Cruz, Puerto Chiapas, and Manzanillo. 9 of them will be installed in the following ports during the years 2007-2008: Ensenada, San Felipe, Guaymas, Topolobampo, Lzaro Crdenas, Altamira, Coatzacoalcos, Dos Bocas and Campeche.

Montoya. R. J. M. (2005): Programa para el Desarrollo de la Red Nacional de Estaciones Oceanogrficas y Meteorolgicas, Instituto Mexicano del Transporte, Proyecto No. VI 21/2005, in Spanish.

Fig. 2.8: Real-time Coastal Tsunami Observing System

Table 2.3: Chronologic summary of tsunamis of local origin observed or recorded along The Mexican Pacific Coast (After Sanchez. A. and Farreras. S.).

EARTHQUAKE DATA TSUNAMI DATA Date Location Area of Origin Magnitude

(Ms) Recording place or

Observation Run up Height

(m) Feb.25,1732 Undefined Guerrero Acapulco 4.0 Sep.01,1754 Undefined Guerrero Acapulco 5.0 Mar.28,1787 Undefined Guerrero >8.0 Acapulco 3.0 8.0 Abr.03,1787 Undefined Oaxaca Pochutla

Juquila 4.0 4.0

May.04,1820 17.299.6 Guerrero 7.6 Acapulco 4.0 Ma.10,1833 Undefined Guerrero Acapulco N/A Mar.11,1834 Undefined Guerrero Acapulco N/A Abr.07,1845 16.699.2 Guerrero Acapulco N/A Nov.29,1852 Undefiined B. California Ro Colorado 3.0 Dic.04,1852 Undefined Guerrero Acapulco N/A May.11,1870 15.896.7 Oaxaca 7.9 Puerto ngel N/A Feb.23,1875 Undefined Colima Manzanillo N/A Abr.14,1907 16.799.2 Guerrero 8.0 Acapulco 2.0 Jul.30,1909 16.899.8 Guerrero 7.4 Acapulco N/A Nov.16,1925 18.5107.0 Guerrero 7.0 Zihuatanejo 7.0-11.0 Mar.22,1928 15.796.1 Oaxaca 7.7 Puerto ngel N/A Jun.16,1928 16.396.7 Oaxaca 7.8 Puerto ngel N/A Jun.03,1932 19.5104.3 Jalisco 8.2 Manzanillo

San Pedrito Cuyutln San Blas

2.0 3.0 N/A N/A

Jun.18,1932 19.5103.5 Jalisco 7.8 Manzanillo 1.0 Jun.22,1932 19.0104.5 Jalisco 7.7 Cuyutln

Manzanillo 9.0-10.0

N/A Jun.29,1932 Jalisco Cuyutln N/A Dic.03,1948 22.0106.5 Nayarit 6.9 Islas Maras 2.0 5.0 Dic.14,1950 17.098.1 Guerrero 7.3 Acapulco 0.3 Jul.28,1957 16.599.1 Aguascalientes 7.9 Acapulco

Salina Cruz 2.6 0.3

May.11,1962 17.299.6 Guerrero 7.0 Acapulco 0.8 May.19,1962 17.199.6 Guerrero 7.2 Acapulco 0.3 Aug.23,1965 16.395.8 Oaxaca 7.3 Acapulco 0.4 Jan.30,1973 18.4103.2 Colima 7.5 Acapulco

Manzanillo Salina Cruz

La Paz Mazatln

0.4 1.1 0.2 0.2 0.1

Nov.29,1978 16.096.8 Oaxaca 7.8 P. Escondido 1.5 Mar.14,1979 17.3101.3 Guerrero 7.6 Acapulco

Manzanillo 1.3 0.4

Oct.25,1981 17.8102.3 Guerrero 7.3 Acapulco 0.1 Sep.19,1985 18.1102.7 Michoacn 8.1 Lzaro Crdenas

Ixtapa Zihuatanejo Playa Azul Acapulco

Manzanillo

2.5 3.0 2.5 1.1 1.0

Sep.21,1985 17.6101.8 Michoacn 7.5 Acapulco Zihuatanejo

1.2 2.5

Table 2.4: Chronologic summary of tsunamis distant (after 1950) origin recorded along The Mexican Pacific Coast (After Sanchez. A. and Farreras. S.)

EARTHQUAKE DATA TSUNAMI DATA Date Location Origin Magnitude (MS) Recording place Run up Height (m)

Nov.04,1952 52.8 N, 159.5 E Kamchatka 8.3 La Paz, B. C. Salina Cruz, Oax. 0.5 1.2

Mar. 09, 1957 51.3 N 175.8 W Aleutian Is. 8.3

Ensenada, B. C. La Paz, B. C.

Guaymas, Son. Topolobampo, Sin.

Mazatln, Sin. Manzanillo

Acapulco, Gro. Salina Cruz, Oax.

1.0 0.2

< 0.1 < 0.1 0.2 0.6 0.6 0.4

May 22, 1960 39.5 S, 74.5 W Chile 8.5

Ensenada, B. C. La Paz, B. C.

Guaymas, Son. Topolobampo, Sin.

Mazatln, Sin. Acapulco, Gro.

Salina Cruz, Oax.

2.5 1.5 0.6 0.2 1.1 1.9 1.6

Nov. 20, 1960 6.8 S, 80.7 W Peru 6.8 Acapulco, Gro. 0.1

Oct. 13, 1963 44.8 N, 149.5 E Kuril, Is. 8.1

La Paz, B. C. Mazatln, Sin. Acapulco, Gro.

Salina Cruz, Oax.

< 0.1 0.1 0.5 0.5

Mar. 28, 1964 61.1 N, 147.6 W Alaska 8.4

Ensenada, B. C. La Paz, B. C.

Guaymas, Son. Topolobampo, Sin.

Mazatln, Sin. Manzanillo

Acapulco, Gro. Salina Cruz, Oax

2.4 0.5 0.1

< 0.1 0.5 1.2 1.1 0.8

Feb. 04, 1965 51.3 N, 19.5 E Aleutian Is. 8.2

Mazatln Manzanillo

Acapulco, Gro. Salina Cruz, Oax.

0.1 0.3 0.4 0.5

Oct. 17, 1966 10.7 S, 78.6 W Peru 7.5 Salina Cruz, Oax. 0.2

May. 16, 1968 41.5 N, 142.7 E Japan 8.0

Ensenada, B. C. La Paz, B. C. Mazatln, Sin.

Manzanillo, Col. Acapulco, Gro.

0.3 < 0.1 0.1 0.4 0.4

Nov. 29, 1975 19.4 N, 155.1 W Hawai 7.2

Ensenada, B. C. Isla Guadalupe, B.

C. Cabo San Lucas, B. C.

Loreto, B. C. Manzanillo, Col.

Puerto Vallarta, Jal. Acapulco, Gro.

Salina Cruz, Oax

0.5 0.4 0.3 0.1 0.3 0.2 0.3 0.3

Jan. 14, 1976 29.0 S, 178.0 W Kermadec 7.3

Cabo San Lucas, B. C. Manzanillo, Col.

Puerto Vallarta, Jal. Acapulco, Gro.

Salina Cruz, Oax

0.1 0.1 0.2 0.2 0.2

Dec. 12, 1979 1.6 N, 79.4 W Colombia 7.9 Acapulco 0.13

2.5 INDONESIA

2.5.1 Tsunami Potential

Indonesia is located at the convergence of three main tectonic plates: the Eurasian, Indo-Australian and Pacific Plates. The Indo-Australian plate sub-ducts beneath the Eurasian plate along the Sunda Arch as part of a greater arc system in the Indian Ocean. Beyond the Sunda Arch, the Banda sector continues eastward, where the oceanic arc collies with the Indo-Australian plate. All around Indonesia are sub-duction zones where the large scale, slow cycle of land is driven by the rivers flowing down mountains coupled with the deep Earth heat driving the plate movements from below. On the perimeter, converging plates slowly store energy resulting it many small, shallow seismic events and the occasional deep earth, high energy event. The concentrated Earth energy flows (sun, tide and deep earth heat) converge on the Islands of Indonesia resulting in much active land building especially by volcanic activity. The sudden release of large amounts of stored energy (as friction) when two plates shift across a broad area caused the catastrophic Aceh Tsunami on 26 December 2004. This giant tsunami was the result of the high intensity, sub-sea Sumatra Earthquake that impacted coastal areas not only in NAD (Nangroe Aceh Darussalam) and North Sumatra provinces of Indonesia but also as far a field as Malaysia, Thailand, Sri Lanka, India, Maldives, and Africa. Other examples of tsunami disasters in the last two decades in Indonesia include Flores (1992) with more than 1950 dead, East Java (1994) with 240 reported deaths, Palu (1996) with 3 lives lost, Biak (1996) with 107 reported deaths, Banggai (2000) with 4 deaths, West Java (2006) with 668 deaths, and Bengkulu (2007) (no data on losses). Indonesia has been affected by Tsunami since recorded history. There are records of more than 100 such events over the last 400 years (Latief et .al, 2000). These records indicate that between 1600 and November 2007 there have been 109 tsunamis. This suggests energy of earthquakes and subsequent tsunamis increasing with time interval between earthquakes and a

recorded tsunami approximately once every four years. The data suggests that frequency has increased in the last half century although it is not certain if this is because of better records and monitoring or reflects greater seismic activity. Certainly the potential for impact of coastal communities has increased greatly in that time. From 1960 - November 2007 there have been 22 significant tsunamis. This indicates that the frequency of tsunamis is around one in every two years. Some of Indonesian coastal areas of highest potential risk by tsunami include: the West coast of Sumatra, South coast of Java, South coast of Bali, North and South coast of Nusa Tenggara, islands of Maluku, North coast of Papua, and most of Sulawesi (Celebes) coast (Fig. 2.9). While the speed and scale of the 2004 tsunami was one main reason for the loss of life and property; non-disaster focused land use planning, lack of awareness, lack of infrastructure for tsunami prevention, no warning system, and the deterioration of the coastal environment also played their part. In the worst hit Aceh region, many buildings were found to have been constructed without compliance to the relevant sections of the building code for earthquakes and tsunami. Other implicating factors included: houses built very close to the sea; no greenbelts, and only remnants of the original mangroves and coastal forests remaining.

Eurasian Pacific Plate

Pl t

--- Potential Tsunami Indo-Australian Plate

BANDA ARCH SUNDA ARCH

Fig. 2.9: Potential tsunami in Indonesia

The Tsunami disaster in Indonesia caused widespread damage and suffering as the ensuing Tsunami wave impacted on the coastal zone. An estimated 300,000 lives were lost. The tsunami run-ups were reported higher than 30 m. As Aceh is relatively close to the Earthquake epi-centre off the coast of Sumatra and the velocity of the Tsunami wave was very fast, there was

little time for alert and evacuation. In the wake of the soul searching in the months after the catastrophe it was concluded that although Indonesians are now more aware of the danger posed to population centres located in coastal areas more needs to be done to pass on information about Tsunamis and how one may more away from the main danger area.

Ulee Lheue Port Figure 2.11 show satellite views of Banda Aceh port before and after the earthquake. As noticed from the comparison of two satellite views, a huge area was damaged by the tsunami and was settled, eroded and scoured due to probably ground liquefaction induced by ground shaking as well as due to the tsunami waves. The ground consists of sandy soil in this area. It is also of great interest that some parts of the dykes of the harbor disappeared. Besides the effects of liquefaction, the flow direction of tsunami waves might have some damaging effects on the missing section of the dykes.

2.5.2 Damage to Ports and Coastal Facilities due to

2004 Aceh (Sumatera) Tsunami At 08:07 a.m. local time on December 26, 2004, there occurred a great earthquake whose epicenter was located off the western coast of northern Sumatra Island at magnitude of 9.0. The quake itself of the earthquake at Banda Aceh, which is the closest city, was estimated five upper or so on the Japanese intensity scale by the Meteorological Agency, but the plate faultline, which is more than 1,000 km long and which extends from off the coast of northwestern Sumatra Island to the neighborhood of the Andaman Nicobar Islands, slipped, and it generated a great tsunami with waves exceeding 20 meters in height. The damage caused by the tsunami affected the whole Indian Ocean area, which turned out to be one of the deadliest natural disasters in human history with more than 200,000 people with missing and dead combined.

(1) Before the earthquake

(2) After the earthquake Fig. 2.10: Investigated area (Northern part of Sumatra

Island) Fig. 2.11: Satellite views of Ulee Lheue port before and after the earthquake Tsunami induced heavy damage to ports and coastal

facilities along the west and north coast of Sumatra Island. Figure 2.10 shows the investigated facilities around Banda Aceh area. The coastal area of Banda Aceh is consists of alluvial flat area around -0.45m to +4.5m from mean sea water level. Most of area bellow the mean sea water level is using as aquaculture ponds.

The plan view of Ulee Lheue port is shown in Figs. 2.12 and 2.13. The residential area is protected by rubble stone (2,000kg-3,500kg) revetment with gentle slope as shown in Fig. 2.14. The severe damaged missing area between residential area and the ferry terminal is using as small boat/fishery boat access port

with submerged breakwater as shown in Figs. 2.13 and 2.14.

Small boat Fishery boat access

Ulee Lheue port

Ferry terminal

Pile supported wharf

Power generator barge

Residential area revetment

Submerged breakwater

Fig. 2.13: Plan view of the revetment and the submerged breakwater (Traced drawing of the picture provided by Departemen Permukiman dan Prasarana Wilayaha, Direktorat Jenderal Sumber Daya Air, Detail Design Panttai Syiah Kuala Kota Banda Ache,2003)

Fig. 2.12: Plan view of Ulee Lheue Port (Traced drawing of the picture provided by Departemen Permukiman dan Prasarana Wilayaha, Direktorat Jenderal Sumber Daya Air, Detail Design Panttai Syiah Kuala Kota Banda Ache,2003 )

Residential Area Revetment

Submerged Breakwater Rubble:2000kg3500kg

The RC building of the port facility collapsed at the ground floor as seen in Fig. 2.10. However, the main cause of collapse was ground shaking rather than the tsunami waves. Large stone blocks were thrown by the tsunami waves over the wharf of the port as seen in Fig. 2.12. However, as shown in Fig. 2.11, just behind the stone rubble revetment at residential area was disappeared. During construction procedure the revetment, naturally deposited sandy dyke was excavated and put stone rubble, then, remolded as shown in Fig. 2.14 top. The remolded water pluvial sand layer should be liquefied during the earthquake motion.

Fig. 2.14: Cross section of revetment and submerged breakwater (Traced drawing of the picture provided by Departemen Permukiman dan Prasarana Wilayaha, Direktorat Jenderal Sumber Daya Air, Detail Design Panttai Syiah Kuala Kota Banda Ache,2003)

The pile supported wharf for ferry boat has no damage during the earthquake motion and the tsunami. However, two pieces rubble (2,000kg-3,500kg) appeared on the deck as shown in Photo 2.19 due to the tsunami wave.

Photo 2.19: Pile supported wharf for ferry boat Although the dolphin for a barge with a power generator was not damaged by the tsunami as seen in Photo 2.18, the barge (Photo 2.20) was displaced from the dolphin to a distance of 3 km inland.

Photo 2.20: Dolphin for a power generator barge

Photo 2.21: Power generator barge The RC building of the port facility collapsed at the ground floor as seen in Photo 2.22. However, the main cause of collapse was ground shaking rather than the tsunami waves because of the second floor with slightly damaged columns(Photo 2.23) was survived during the tsunami waves. The ferry terminal building which RC

pile-deck structure without shear walls collapsed at ground floor columns acted as a base isolation system, the second and top floors were survived.

Rubble

Photo 2.22: Ferry terminal (crushed 1st floor)

Photo 2.23: Ferry terminal (2nd floor) Port for the Cement Factory The port facility for the cement factory was also damaged by the tsunami. The 5m height trapezoidal cross section shaped gravity type parapet was overturned as shown in Photo 2.24. Totally, three blocks were overturned, two blocks of the parapet were overturned outside direction of the port and other one was overturned opposite direction. To investigate the overturned scenario, detail consideration of the layout of the parapet and tsunami wave action should be needed.

Photo 2.24: Damaged seawall at cement factor Photo 2.25 shows the damage of pile supported wharf due to the capsized ship impact force during the tsunami. A pile supported wharf showed good performance during tsunami waves in Ulee Lheue Port, however, it must be considered drifting objects impact force against the structures.

Photo 2.25: Damaged pile supported wharf at cement factory

Remarks From the site observation/investigation of Banda Aceh coastal area facilities, following findings are summarized. (1) It was quite difficult to distinguish between

damages of port/coastal area facilities caused by the earthquake motion and by the tsunami wave action. Significant damages were caused by scour away phenomenon and impact force of drifting objects during the tsunami. However, the possibility of double action effect by the earthquake motion and tsunami wave should be considered.

(2) The pile-deck structures such as pile supported wharf, pile supported dolphin and the ferry terminal pile-deck structures (pilotis style) showed good performance during tsunami wave.

2.6 SRI LANKA

2.6.1 Lessons Learned from Extreme Storm Wave Attack

The failure, in the late seventies and early eighties, of many large rubble mound breakwaters under extreme wave attack led to the careful examination of physical processes of wave-structure interaction. It was established that the interaction of waves with a rubble mound breakwater results in a complex flow pattern involving unsteady, two phase flow. Such flow generates equally complex force fields. Basic research findings have highlighted some of the related factors which have contributed to the failures of rubble mounds. Although most of the failures related to breakwaters armoured with large concrete units, these findings are equally applicable to breakwaters armoured with rock. Such structures are widely used in Sri Lanka for the construction of breakwaters for fishery harbours and revetments for coast protection. Investigations have revealed that failures were not due to one particular reason and that several different factors contributed to these disasters. However, it was widely accepted that breakwater designers have been engaged in excessive extrapolation beyond experience without recognizing the limits of the existing state of the art of the traditional breakwater design. Among the important issues identified with failures included following,

Under estimation of the design wave climate Inadequate understanding of the

hydro-geotechnical aspects of wave action and flow through porous structures

Poor assessment of wave induced loads and resulting force domain

Factors leading to the sudden collapse of slopes Need to understand the inter-relationship among

different failure modes (i.e. clear understanding of the fault tree)

Limitations of adopting standard hydraulic model investigations for the total design

Research findings have led to the review of design procedures, development of new concepts and further examination of alternative design practices. . One such alternative is the use of dynamically stable berm breakwaters which seems to have a number of advantages and have not been used in Sri Lanka.

2.6.2 Lessons Learnt from Tsunami Wave Attack

The Indian Ocean Tsunami of December 2004 caused widespread damage to coastal structures and breakwaters around the island. The type of hydraulic regime generated by the tsunami was considerably different to that of extreme storm wave attack. Many breakwaters were completely overtopped by the highest wave with a large mass of water flowing over the breakwater as the long period tsunami wave moved forward to inundate the coastal zone. The water level of the incoming wave would have been several meters higher than the crest level. For the rest of waves of the tsunami wave cycle breakwaters were subjected to overtopping and a force regime more on the lines of extreme wave attack. On investigating the damage caused to breakwaters it is evident that although considerable damage took place they have performed reasonably well in withstanding the hydraulic and force regime imposed by the tsunami wave cycle. In comparison with the tsunami wave heights observed along the coastline, greater damage could have been expected. Perhaps this could be explained by the characteristics of the tsunami wave. The high amplitude tsunami waves of very long period have propagated over the breakwaters located in deep water and imposing a velocity and force regime of the different components. This type of attack is different to continuous high amplitude wave attack on breakwaters as witnessed in the presence of storms. It is evident that breakwaters have certainly dissipated part of the wave energy of the incoming tsunami wave while incurring damage. This is evident by comparing the damage of buildings inside the harbours under the shadow of the breakwater and those of similar buildings outside the harbour. Field investigations were conducted along the western and southern coasts to investigate the manner in which breakwaters of fishery harbours and coastal structures in the near vicinity of the harbours had performed during the tsunami. The extreme conditions which these structures are usually subjected to are the storm waves under monsoonal conditions. The damages arising from the tsunami follow a very similar pattern and can be categorized as follows.

1. Breakwater