第27回ジオダイナミクスセミナー
　　　Geodynamics　Seminar

　「Rayleigh wave group velocity studies across the
　　northwest Pacific Ocean and northern India Ocean」　
　　　　　　　　 　　　
　　　講　師：Dr. D. D. Singh（センター外国人客員教授）
　　　　　　　　　　　　　　　

　　　　　主催　：　愛媛大学地球深部ダイナミクス研究センター
　　　　　日時　：　２００１年１２月７日（金）　午後17時〜
　　　　　場所　：　愛媛大学理学部講義棟　２０１教室

　　　　　　　　

要　旨
　The fundamental mode Rayleigh waves generated by 27 earthquakes and recorded at eleven digital broadband seismic stations of Ocean Hemisphere project (OHP) network of Japan in the northwest Pacific Ocean are analysed to estimate the Rayleigh wave group velocity for about 160 paths at the varying time periods from 10 to 50s using the multiple filter analysis technique. The inversion of Rayleigh wave group velocity data shows the presence of a low velocity zone (LVZ) above the Moho depth for the eastern and western propagation paths. Another LVZ is also estimated in the study area below the Moho for the central path of propagation in the study area.
　The group velocity tomography has been obtained at different time periods (10-50s) for Rayleigh wave.The observed slow and fast velocity anomalies are well correlated with the tectonics of the region. The effect of the subduction of the Philippine and Pacific plates beneath the Eurasian plate under the southeast of Japan, where a triple junction of the three plates exists, is also reflected in the group velocity tomograms.
　Similarly, the Rayleigh wave group velocity studies beneath the Bay of Bengal and north Indian Ocean has been carried out, which shows the interesting results and will be discussed in detail.


　
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