15th GRC International Frontier Seminar

Prof. Hiroo Kanamori
Seismological Laboratory, California Institute of Technology, USA
(日本学術振興会外国人著名研究者招へい事業により京都大学に滞在中)

27 April 2006　10:30-12:00
Room 101, Kogi-to Bldg, Faculty of Science, Ehime University

　　Lessons from the 2004 Sumatra-Andaman Earthquake

　The 2004 Sumatra-Andaman earthquake (Mw=9.2) is one of the greatest earthquakes ever recorded. In terms of its physical size, it is comparable to the1960 Chilean (Mw=9.5), and the 1965 Alaskan (Mw=9.2) earthquakes. However, the damage caused by this earthquake is far greater than that caused by other great earthquakes. The 2004 Sumatra-Andaman earthquake has been studied in great detail over broad time scales, from a fraction of seconds to hours and months, using the modern seismic data available from global seismic networks and the Global Positioning System (GPS) data. The findings obtained mainly from seismic data will be summarized, and the unique features of this earthquake, and possible directions of research to minimize the impact of great earthquakes on our society. will be discussed.


　　High-density Waveform data and their implications for
　 　　　　　　the Slab Structure beneath Japan
　　　　　(A recent Caltech Study by M. Chen, J. Tromp, D. Helmberger,
　　　　　　　　　　　　　　　　and H. Kanamori)

　The waveforms from deep-focus earthquakes near Japan recorded by the Hinet network stations exhibit a systematic variation depending upon the geometrical relationship between the ray path and the deep seismic zone. First, the general characteristics of such variations of the P waveforms will be explained in term of the slab structure determined by the studies of Zhao and his coworkers. Then, more detailed results obtained by forward waveform modeling conducted by Chen and her coworkers using both P and S waves will be presented. The results suggest existence of a significant low-velocity layer along the upper boundary of the slab beneath Tohoku down to the depth of about 300 km.　


　　



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主催：愛媛大学地球深部ダイナミクス研究センター