UTokyo Repository 東京大学

UTokyo Repository >
131 地震研究所 >
東京大学地震研究所彙報 >

このページ(論文)をリンクする場合は次のURLを使用してください: http://hdl.handle.net/2261/13123

タイトル: A Destructive Shallow Small Earthquake : The 1992 Tsunan Earthquake of M4.5 in Southern Niigata Prefecture, Central Japan
その他のタイトル: 破壊的浅発小地震 : 新潟県南部津南の地震(1992年12月27日,M4.5)
著者: TSUKUDA, Tameshige
OKI, Yasue
著者(別言語): 佃, 為成
大木, 靖衛
発行日: 1994年9月30日
出版者: 東京大学地震研究所
掲載誌情報: 東京大学地震研究所彙報. 第69冊第1/2号, 1994.9.30, pp. 19-38
抄録: A small earthquake of M4.5 severely attacked Tsunan Town, Niigata Prefecture on December 27,1992. Unexpectedly destructive damage to school buildings and gymnasiums was mainly attributed to an extremely shallow focal depth of 2-3km within the Tertiary layer, which is as thick as 5-6km. The accuracy of the depth determination is estimated to be within 1km. A high Vp/Vs ratio of 2.0 measured locally also supports the shallow focal depths. We have no seismometric reports of a shallow earthquake with magnitude greater than 4 whose fractured region is entirely within the Tertiary layer other than this paper. The epicentral region is tectonically complicated, where the Shinano River Seismic Zone and the Naoetsu-Choshi Line deduced from Bouguer gravity anomalies cross each other. Probably due to this complexity, the earthquake generating stress of the mainshock indicates NNW-SSE compression, while the major aftershocks are generated by WNW-ESE compresional stresses which are in harmony with the surrounding stress field. This earthquake is followed by a comparatively small number of aftershocks, and preceded by microearthquake activity about 3 months before and during the 12 hours before the mainshock. The aftershock region is separated into three spots, one of which was the source region of the precursory activity 3 months before.
URI: http://hdl.handle.net/2261/13123
ISSN: 00408972


ファイル 記述 サイズフォーマット
ji0691002.pdf1.4 MBAdobe PDF見る/開く



Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - ご意見をお寄せください