The tragedy of the 2004 Indian Ocean tsunami has led to a rapid expansion in science directed at understanding tsunami and mitigating their hazard. A remarkable cross-section of this research was presented in the session: Tsunami Generation and Hazard, at the International Union of Geodesy and Geophysics XXIV General Assembly in Perugia, held in July of 2007. Over one hundred presentations were made at this session, spanning topics ranging from paleotsunami research, to nonlinear shallow-water theory, to tsunami hazard and risk assessment. A selection of this work, along with other contributions from leading tsunami scientists, is published in detail in the 28 papers of this special issue of Pure and Applied Geophysics: Tsunami Science Four Years After the Indian Ocean Tsunami. Part I of this issue includes 14 papers covering the state-of-the-art in tsunami modelling and hazard assessment. Another 14 papers are published in Part II focusing on observations and data analysis.
This volume features contributions from the first Meeting of the Tsunami Commission after the big 2004 tsunami in the Indian Ocean. It presents consolidated findings based on hydrophone records, seismometer readings, and tide gauges. In addition, the volume provides reports of post-tsunami surveys and numerical simulations for tsunamis such as the 2004 Indian Ocean event. It also details tsunami dangers and early warning systems.
The 2004 Indian Ocean tsunami was triggered by a 9. 15 magnitude earthquake (MELTZNER et al. , 2006; CHLIEH et al. , 2007) that occurred at 0:58:53 GMT, 7:58:53 LT (USGS) (t ). The epicenter was located at 3. 3 N, 95. 8 E (Fig. 1) with a focal depth of EQ approximately 30 km. The earthquake was responsible for a sudden fault slip estimated on average from 12–15 m (SYNOLAKIS et al. , 2005; LAY et al. , 2005) to 20 m (FU and SUN, 30 2006). The seismic moment estimate (Mo = 1. 3 5 9 10 dyne-cm), based on the Figure 1 Locations of video recordings, recovered clocks, and reliable eyewitness observations. 1: Coastal plains ?ooded by the tsunami; 2: non-?ooded coastal plains; 3: uplands. Insert 3D-map showing the Sumatra Island, the studied area, and the epicenter of the 26/12/2004 earthquake. The video taken at Uteuen Badeue, on the eastern edge of the Banda Aceh Bay, was recorded by the chief of the Fishery Regional Of?ce from the top of a cliff. The movie that was shot near the Baiturrahman mosque in downtown Banda Aceh has been shown worldwide on TV. The one at Peukan Bada has been recorded during a wedding party. The last two movies were analyzed in detail in order to calculate the tsunami velocity (FRITZ et al. , 2006). Vol.
The 1993 Southwest Hokkaido Earthquake of Magnitude 7. 9 (July 12, 22: 17 JST) caused serious tsunami disasters in the southwestern part of Hokkaido, particularly on Okushiri Island (a tiny island off the southwest coast of Hokkaido with a population of about 4,500 at the time of earthquake). Of 230 casualties, including 28 missing, about 200 deaths are attributable to the tsunami. We have conducted detailed field surveys of tsunami disasters to learn lessons from this costly natural experiment for the future prevention of similar tsunami disasters. Our field work was conducted in four surveys totaling 39 days. During the first field survey (July 16 through July 21, 1994), we worked mostly on the estimation of the subsidence of Okushiri Island during the earthquake. Hence, our main work on tsunami disasters initiated from the second field survey (July 31 through Aug. 15, 1994). Several groups have conducted detailed surveys of the distribution of tsunami runup height as measured from the level of sea water (TsUJI et al. , 1 994a, b; MATSUTOMI and SHUTO, 1994; GOTO et al. , 1994). Such a precise runup height distribution is essential for characterizing tsunami, including its overall size. Indeed, the height distribution is the fundamental data for inferring earthquake source parameters through the simulation of tsunami generation (TAKAHASHI et al. , 1994; IMAMURA et al. , 1994; TSUJI et al. , 1994a; SATAKE and TANIOKA 1994; ABE, 1994; TANIOKA et al. , in review).
This book contains 20 papers reflecting the state-of-the-art tsunami research. Most of them were presented at the two international meetings held in 2003: the 21st International Tsunami Symposium, held on July 9 and 10th as a part of IUGG general assembly in Sapporo, Japan, and an International Workshop on Tsunamis in the South Pacific, held on September 25 and 26th in Wellington, New Zealand. More recent work, including the field survey report of the Tokachi-oki earthquake tsunami of September 26, 2003, is also included. Synolakis and Okall summarize the survey results of International Tsunami Survey Teams, as well as seismological and numerical modelling studies of 15 tsunami events occurred between 1992 and 2002. In this active decade of tsunami disasters, the tsunami community has learned how to organize ITST, describe, document and share the results of surveys. The authors also propose a method to discriminate the seismic tsunamis from landslide tsunamis based on the observed runup heights, and demonstrate it for the recent tsunamis. Power et al. report the tsunamis generated by the 2003 Fiordland, New Zealand, earthquake (M 7. 2). This earthquake generated two kinds of tsunamis; a local large (4-5 m) tsunami generated by rockslide in a sound, and a smaller tsunami generated by earthquake fa aulting and detected on tide gauges in Australia. Three papers discuss volcanic tsunamis in the western Pacific region. Nishimura et al. report the tsunami from the 1994 eruption of Rabaul volcanoes.