Field Survey of the Sumatra-Andaman Earthquake Tsunami Survey Report: Field Survey of the Tsunami Caused by the Sumatra-Andaman Earthquake of December 26, 2004 and the Restoration of Impacted Inland Water Bodies in Sri Lanka £ £ Anil C. Wijeyewickrema £1, Shusaku Inoue 2, Priyantha Gunaratna 3, £ Manoj Madurapperuma £1, Hiroyuki Matsumoto 4, £ Hiroyuki Miura £5, and Toru Sekiguchi 6 £1Department of Civil Engineering, Tokyo Institute of Technology, Japan E-mail: [email protected] £2Department of Built Environment, Tokyo Institute of Technology, Japan £3Department of Civil Engineering, University of Moratuwa, Sri Lanka £4Japan Agency for Marine-Earth Science and Technology, Japan £5Center for Urban Earthquake Engineering, Tokyo Institute of Technology, Japan £6Department of Architecture and Building Engineering, Tokyo Institute of Technology, Japan [Received May 31, 2006; accepted July 10, 2006] The magnitude 9.0 Sumatra-Andaman earthquake on December 26, 2004, was one of the world’s largest since 1900. The devastating tsunami resulting from it caused more casualties than any previously reported tsunami. This paper describes two field visits to assess tsunami damage in Sri Lanka by a team of Japanese and Sri Lankan researchers and environ- mental restoration plans for tsunami-impacted inland water bodies. The first field visit, Dec. 30, 2004-Jan. 04, 2005, covered western, southwestern and southern Sri Lanka and included the cities of Beruwala, Pere- liya, Hikkaduwa, Galle, Talpe, Matara, and Hamban- tota. The second field visit, March 10-18, 2005, cov- ered northeastern, eastern, southeastern and southern Sri Lanka and included Trincomalee, Kuchchaveli, Pasikkudah, Batticaloa, Arugam Bay, Yala (National Park), and Kirinda. Eyewitness information on wave arrival times is also discussed. Keywords: damage, field survey, Sumatra-Andaman earthquake, Sri Lanka, tsunami Fig. 1. Epicenter of Sumatra-Andaman earthquake and sur- rounding countries. Indonesia, Sri Lanka, India and Thai- land were most seriously affected. 1. Introduction The facts of the Sumatra-Andaman earthquake are as or missing in Indonesia alone. Other countries reporting follows: magnitude: 9.0; time: 00:58:53 (Coordinated large numbers of dead or missing due to the tsunami were Universal Time), December 26, 2004; local time at the Sri Lanka, with 35,322; India, with 18,045; and Thailand, Æ epicenter: 07:58:53, December 26, 2004; location: 33 N with 8,212 (UN Office of the Special Envoy for Tsunami Æ 99 E; depth: 33km; region: off the west coast of North- Recovery, 2006). The location of the epicenter and sur- ern Sumatra (USGS, 2004). Earthquakes since 1900 with rounding countries are shown in Fig. 1. magnitudes 9 0 include the 1960 Great Chilean earth- Field visit routes and main cities covered are shown quake, magnitude 9.5; the 1964 Prince William Sound, in Fig. 2. The first visit, from Dec. 30, 2004, to Jan. Alaska earthquake, 9.2; and the 1952 Kamchatka earth- 04, 2005, covered western, southwestern and southern quake, 9.0 (USGS, 2006). The tsunami generated by the Sri Lanka and included the cities of Beruwala, Pere- Sumatra-Andaman earthquake resulted in more casual- liya, Hikkaduwa, Galle, Talpe, Matara, and Hambantota. ties than any previous tsunami – 167,736 people killed The second visit, from March 10 to 18, 2005, covered Journal of Disaster Research Vol.1 No.1, 2006 123 Wijeyewickrema, A. C. et al. Route 1 Route 2 Kuchchaveli Punkadimalai Nilaveli Trincomalee Pasikkudah Navatkuda East Batticaloa Kalmunai Akkaraipattu Komari Colombo Arugam Bay Beruwala Yala Pereliya Palatupana Hikkaduwa Talpe Kirinda Galle Hambantota Matara Fig. 2. Field visit routes. Route 1: Colombo, Beruwala, Pereliya, Hikkaduwa, Galle, Talpe, Matara, and Hambantota. Route 2: Colombo, Trincomalee, Kuchchaveli, Pasikkudah, Batticaloa, Arugam Bay, Yala (National Park), and Kirinda. Fig. 3. Pereliya: Although this area is about 200 m inland from the coast, an express train was washed away by the tsunami and about 1,000 people died. the northeastern, eastern, southeastern and southern Sri of Hikkaduwa on the southwest coast, where a train Lanka and included Trincomalee, Kuchchaveli, Pasikku- stopped between stations was swept off the tracks when dah, Batticaloa, Arugam Bay, Yala (National Park), and the tsunami struck, taking the lives of about 1,000 peo- Kirinda. The objectives of the field visits were to investi- ple (Fig. 3). Most low-cost masonry houses located in gate damage caused by the tsunami and to obtain eyewit- the coastal region were completely destroyed, while some ness information about wave arrival times. two-story buildings with concrete columns and beams Section 2 covers tsunami damage and tsunami ar- sustained less damage. Fig. 4 shows destroyed masonry rival times. Section 3 discusses restoration of tsunami- houses near the Hambantota coast. Damage observed in impacted inland water bodies. Yala National Park and Palatupana on the second field trip is shown in Figs. 5 and 6. More photographs of tsunami damage taken during the field visits are provided by Wi- 2. Tsunami Damage and Tsunami Arrival jeyewickrema et al. (2005) [8] and Wijeyewickrema et Times al. (2006) [9]. The numbers of dead, missing, and dam- aged houses in the affected districts are given in Appendix On the first field trip to the west, southwest and south, A. damage caused by the tsunami was generally severest Arrival times of the first and maximum waves are in the regions between Galle and Hambantota and ex- shown in Fig. 7. The first wave arrived at the eastern tended several hundred meters inward from the coast. coast between 08:20 and 09:00, the southern coast be- One of the most tragic events occurred at Pereliya north tween 09:00 and 09:22, and the western coast between 124 Journal of Disaster Research Vol.1 No.1, 2006 Field Survey of the Sumatra-Andaman Earthquake Tsunami Fig. 4. Hambantota: Masonry houses located within a few hundred meters of the coast were completely destroyed, but some two-story buildings with concrete columns and beams sustained less damage. Fig. 5. Yala National Park: Many tourists lost their lives at this location. Fig. 6. Yala Safari Hotel in Palatupana: This tourist hotel was completely destroyed. Journal of Disaster Research Vol.1 No.1, 2006 125 Wijeyewickrema, A. C. et al. (a) (b) Fig. 7. (a) Arrival time of the first wave. (b) Arrival time of the maximum wave. Missing numbers shown by dashes indicate that data was unavailable. Fig. 8. Tide-gauge record from Colombo Fisheries Harbor: (a) Dec. 25, 2004-Jan. 01, 2005, and (b) 09:00-20:00, Dec. 26, 2004. Dotted lines in (b) indicate tide was not properly recorded. Arrow A indicates the first arrival recorded at 09:48 and arrow B the probable arrival of the maximum wave at about 12:00. 09:30 and 09:55. The maximum wave arrived at the east- waves preceded the maximum wave. The wave period on ern coast between 08:35 and 09:23, the southern coast be- the western coast was 30 min and on the eastern coast tween 09:13 and 09:50, and the western coast between 30 min. Before the maximum wave, the sea retreated 09:55 and 12:00. The velocity of the maximum wave for several hundred meters in some locations. along the western coast is observed to be slower than that Data from the tidal observation station of the National of the first wave. Most likely at most locations one or two Aquatic Resources Research and Development Agency 126 Journal of Disaster Research Vol.1 No.1, 2006 Field Survey of the Sumatra-Andaman Earthquake Tsunami Fig. 9. Karagan Lewaya in Hambantota District. (NARA) located in the Colombo Fisheries Harbor is tota town. The term “Lewaya” means “saltern,” indicating shown in Fig. 8. The unusual water-surface elevation its past use for salt extraction. The lagoon covers an area recorded on Dec. 26 is due to the tsunami and contin- of 8.35 km2 and is 3.5 km long and 1.2 km wide. The ued until Dec. 29. The detailed tidal record of Dec. 26 average depth is about 0.9 m. Karagan Lewaya is consid- is shown in Fig. 8(b). The first wave of the tsunami ered one of the best birdlife habitats in Sri Lanka and is is recorded at 09:48 with a water-surface elevation of an area of special ecological interest. 2.6 m. Unfortunately, this tidal record does not contain the The 58 km2 undulating catchment of Karagan Lewaya full time history and two time intervals are not properly includes dry zone scrub woodland, numerous village recorded. It is possible that the maximum wave arrived at tanks, associated paddies, vegetable and forest planta- about 12:00 consistent with eyewitness data. More details tions, a substantial part of Hambantota urban area, and of arrival times are discussed in Inoue et al. (2006) [3]. a strip of coastal sand dunes to the south. Fronting the dunes is a wide beach about 3 km long contained between rocky headlands. The Bombuwetiya sea outlet canal just 3. Environmental Restoration of Tsunami- to the northeast of Hambantota town is the only connec- Impacted Inland Water Bodies tion between the lagoon and the sea, terminating in a gated control structure. This outlet is mostly blocked due to the Inland water bodies seriously affected by the tsunami accumulation of beach sand. It has been reported that in must be restored. Here we focus on the Karagan Lewaya the high flood years of 1957 and 1969, this sand bar had coastal lagoon on the southern coast (Fig. 9). The prob- to be breached to drain lagoon water. lems associated with this site are typical of the impact of the tsunami on inland water bodies in Sri Lanka as de- 3.2.