著者

鷺谷 威

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.52, no.1, pp.111-120, 1999-06-30 (Released:2010-03-11)

参考文献数

17

被引用文献数

2 3

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Conventional triangulation and leveling data are analyzed to estimate crustal movements associated with the 1948 Fukui earthquake and its fault model. Horizontal displacement vectors at 84 triangulation points and vertical displacements of 82 leveling benchmarks are inverted to estimate slip distribution on the fault plane. Although two surface traces of faults were found after the earthquake, most of the seismic moment was released from a main fault on the west, and an eastern sub-fault played only a complementary role. The dip angle of the main fault is not well constrained. However, geodetic data are fairly consistent with an assumption of a vertical fault. Estimated fault mechanism is mostly left-lateral strike slip with the maximum slip of 6m. The seismic moment of the Fukui earthquake is estimated as 2.4×1019Nm (Mw=6.8), which is consistent with another estimation based on seismic data. The Fukui earthquake was comparable to the 1995 Kobe earthquake in its size, but the heterogeneity of slip distribution is different each other. The Fukui earthquake fault had a much longer preparatory period before the 1948 event, and fault strength might be completely recovered before the earthquake, which resulted in a rather homogeneous slip distribution. In the case of the 1995 Kobe earthquake, a short recurrence time along the Rokko-Awaji fault after the 1596 Keicho-Fushimi earthquake might result in a rather heterogeneous slip distribution.