日本地球惑星科学連合2016年大会

講演情報

ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS34] 2016年熊本地震および関連する地殻活動

2016年5月25日(水) 17:15 〜 18:30 ポスター会場 (国際展示場 6ホール)

17:15 〜 18:30

[MIS34-P08] 2016年熊本地震にともなう地震活動の時空間発展:4月14日M6.5地震後の余震域の拡大

*加藤 愛太郎1福田 淳一1中川 茂樹1 (1.東京大学地震研究所)

キーワード:熊本地震、地震活動、余震域の拡大

A series of powerful earthquakes and the following aftershocks has struck the Kumamoto area in Kyusyu, Japan, from 14th April, 2016. These powerful earthquakes have caused destructive damages in the central part of Kyusyu. We relocated a bunch of earthquakes associated with the 2016 Kumamoto earthquake (~2700 events), applying a double-differential code to arrival time data set constructed by JMA, and waveform cross-correlation technique. Then, we newly detected numerous earthquakes using these relocated earthquakes as template events, applying a matched filter technique to continuous waveform data recorded at 35 seismic stations in the central Kyusyu area. Most of relocated hypocenters are aligned along nearly vertical planes or north-westward dipping plane. Hypocenters before M7.3 earthquakes were concentrated near surface traces of active faults in northernmost segment of “Hinagu” and a part of “Futagawa”. After M7.3 earthquake, they shifted toward northwest ward and aligned gently northwest ward dipping plane. Early aftershocks following M6.5 earthquake clearly expanded along fault strikes during a half day. But, aftershock zone slightly continued to expand perpendicular to fault strikes until the generation of M7.3 earthquake. The M7.3 earthquake has immediately boosted a widespread seismicity along the northeastern extension of the Futagawa fault, as well as the northwestern section of the Hinagu fault.