第58回ジオダイナミクスセミナー
　　　Geodynamics　Seminar

　　　　　　　　　　（後　半）

　　“Tomographic evidence for in situ material
　　　heterogeneities at the 2001 Bhuj earthquake
　　　hypocenter: A cause of rupture nucleation

　　 　Dr. O. P. Mishra (愛媛大学博士後期課程2年)
　　　　　　　　
　　　　　　　　主催　：　愛媛大学地球深部ダイナミクス研究センター
　　　　　日時　：　２００３年１月２４日（金）午後17時〜
　　　　　場所　：　愛媛大学理学部講義棟　２０１教室　　　

要　旨
　We have addressed the cause of genesis of the 2001 destructive Bhuj (23.4 N, 70.3 E; Mw 7.6), India earthquake tomographically, which have inflicted huge economic and human life losses. Detailed seismic velocity and Poisson's ratio structures of the source region are synthesized using high-quality P and S wave arrival time data from well relocated 331 Bhuj aftershocks recorded by a temporary seismic network. Quantitative estimations of crack density parameter, saturation rate and porosity parameter from seismic velocities and Poisson ratio are made to assess in situ material heterogeneities at the 2001 Bhuj mainshock hypocenter. This study suggests the possibility that earthquake occurrence is closely related to the in situ material heterogeneities rather than lithologic conditions alone, which will be discussed in the forthcoming seminar (January 24, 2003) with support of many pieces of evidence.



　　　　　　　　問い合わせ先：山崎　大輔 　TEL　　　（089）927-8408
　　　 　　　　　　　　　　　　　　　　E-mail　　yamazaki@sci.ehime-u.ac.jp