北海道大学地球物理学研究報告 = Geophysical bulletin of Hokkaido University;第81号

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3次元速度構造を考慮した襟裳岬周辺における地震の震源決定

椎名, 高裕;高橋, 浩晃;勝俣, 啓;一柳, 昌義

Permalink : http://hdl.handle.net/2115/68477
JaLCDOI : 10.14943/gbhu.81.33

Abstract

 In order to evaluate differences in an earthquake distribution in one- or three-dimensional velocity structures, we tried re-determinations of locations of earthquakes occurred around the Erimo cape, Hokkaido, Japan, in the three-dimensional heterogeneous model. Because of lowvelocity anomaly developed beneath the Hidaka mountain range, the relocated earthquakes mark that their focal depths tend to decrease. The maximum focal depth change is about 15 km. These changes of relocated earthquakes from those estimated in the one-dimensional model suggest that precise determinations of hypocenter considering realistic, three-dimensional velocity structure would improve our understandings for seismic activity and their focal mechanism around the Erimo cape.

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