地震 第2輯
Online ISSN : 1883-9029
Print ISSN : 0037-1114
ISSN-L : 0037-1114
駿河湾西岸域の地震活動に現れた静穏化現象
吉田 明夫前田 憲二
著者情報
ジャーナル フリー

1990 年 43 巻 1 号 p. 27-42

詳細
抄録

Seismic quiescence which has recently appeared in the west coast region of Suruga Bay is investigated. The quiescence is clearly recognized for earthquakes with M≥2.5 since the beginning of 1988. Southern boundary of the quiescence region corresponds to the Irozaki-Shizuoka tectonic zone and its extension to the north-west. However, the whole focal region of the expected Tokai earthquake and its surrounding areas show quiescence since the middle of 1988, when earthquakes with M≥3 are considered. The seismic quiescence seems to have started first in the northern part and extended to the south. The feature that the Irozaki-Shizuoka tectonic zone forms boundary of the quiescence region is very meaningful when it is combined with the fact that a gap exists in the hypocentral depth of earthquakes at the tectonic zone. It suggests that the Philippine Sea slab is split at the Irozaki-Shizuoka tectonic zone and the stress states in the two segments of both sides are more or less independent. It is noted that seismic activity in the regions where the quiescence appeared had been high in the long period of recent several decades.

著者関連情報
© 社団法人日本地震学会
前の記事 次の記事
feedback
Top