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-P24] 2016年熊本地震に関連する地震活動と重力異常水平勾配分布

*工藤 健1山本 明彦2 (1.中部大学 工学部 共通教育科、2.愛媛大学 大学院 理工学研究科)

キーワード:2016年熊本地震、重力異常、地震活動

Relationship between distributions of shallow earthquakes and gradients of gravity anomaly field in and around the focal area of the 2016 Kumamoto Earthquake is investigated. In this session, we will present Bouguer anomaly maps, Bouguer anomaly horizontal gradient maps, and some graphs showing relations between gravity anomaly gradients and spatial distributions of hypocenters related to the 2016 Kumamoto Earthquake.

Zones with steep horizontal gradient of gravity anomaly field are presumably caused by faults bounding different density structures in the crust. On the other hand, most shallow earthquakes are supposed to be caused by dislocations at faults in the crust. From both presumptions, it follows that the distribution of epicenters should be overlapped with that of the steep gravity gradient zones. Kudo and Kono (1999) verified the overlap in Southwest Japan.

In the case of the 1995 Hyogo-ken Nanbu earthquake, however, very low seismicity along the steep gradient zone of gravity anomaly was followed by the mainshock (Kudo and Kono, 1999). The preliminary report for the case of the 2016 Kumamoto Earthquake will also be presented.