第82回ジオダイナミクスセミナー
　　　Geodynamics　Seminar

　　　　　　　　　
　"The 2003 Miyagi-oki earthquake: Fine structure of the
　 subducting Pacific slab "

　　　　　講師：Dr. O. P. Mishra (愛媛大学博士3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１２月５日（金）午後17時〜
　　　　　場所　：　愛媛大学理学部講義棟　２０１教室　　　

要　旨
　The May 26, 2003 Miyagi-oki intra-slab earthquake (Mw 7.0) has provided an unusual opportunity to improve our understanding of the detailed structure of the subducting Pacific slab beneath northeast (NE) Japan. A fine 3-D seismic imaging of the subducting Pacific slab beneath NE Japan using the Miyagi-oki (Mw 7.0) aftershock sequence along with a large number of sub-oceanic earthquakes suggests the existence of strong heterogeneity within the slab. The distinguishable Vp anomaly within the subducting slab may be attributed to some compositional variations within the slab and / or due to pre-existing faults / fracture zones in the subducted oceanic crust and mantle beneath NE Japan region, which in turn may have induced the May 26, 2003 Miyagi-oki mainshock (Mw 7.0) and its aftershock sequence by dehydration embrittlement.






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