HR: 10:50h
AN: OS22B-03 INVITED     [Abstracts]
TI: Probabilistic Tsunami Hazard Analysis in Japan
AU: * Satake, K
EM: kenji.satake@aist.go.jp
AF: Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba, 305-8567 Japan
AB: Several projects for estimating tsunami hazard for the Japanese coasts are ongoing. I will introduce four of them, two by the government and the others by professional society and a research institute. The Earthquake Research Committee of the Headquarters of Earthquake Research Promotion of the Government (http://www.jishin.go.jp/main/index-e.html) has evaluated the probabilities of large subduction-zone earthquakes, as well as inland earthquakes on active faults, in and around Japan. In the Tokachi-oki region along Kuril Trench, for example, the probability of an M~8 earthquake occurrence by 2033 was estimated as ~ 60 %. Six months after this evaluation has publicized, the September 26, 2003 Tokachi-oki earthquake (M 8.0) took place and generated up to 4 m of tsunami on the Pacific coast of Hokkaido. Similarly high probabilities (> 40%) of M~8 event have been estimated for parts of Nankai Trough, Japan Trench and Kuril Trench. Central Disaster Management Council of the Cabinet Office has estimated earthquake and tsunami hazards for Nankai Trough (Tokai, Nankai and Tonankai earthquakes). They established scenario sources of tsunami, estimated the coastal tsunami heights (on 50 m grids), and assessed the damage on human, structures, and lifelines. The results are used for countermeasures and disaster prevention by the coastal communities, local and national governments. One of the outcomes is large-scale coastal hazard maps. Similar projects for Japan and Kuril Trenches has recently started. Tsunami Subcommittee of Japan Society of Civil Engineers (Annaka et al., this meeting) is making probabilistic tsunami hazard curves (tsunami heights as a function of its exceeding probability) for specific coastal sites. The hazard analysis is based on tsunami numerical simulations from earthquake faults. Logic-tree approach is adopted to evaluate the fault parameters. Geological Survey of Japan is making large-scale (1:25,000) tsunami inundation maps, as well as smaller-scale (1:500,000) map for coastal tsunami heights, based on the studies of tsunami deposits (Nanayama et al., Nature, 2003) combined with tsunami numerical simulation for possible sources. The maps will be released as CD-ROM.
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
DE: 4546 Nearshore processes
DE: 4564 Tsunamis and storm surges
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting