著者

古村 孝志 竹内 宏之

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.116, no.3-4, pp.431-450, 2007-08-25 (Released:2009-11-12)

参考文献数

48

被引用文献数

5 6

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The Tokyo metropolitan area is known to have been struck by large earthquakes due to the subduction of the Philippine Sea Plate and the Pacific Plate beneath the North American plate. Recent damaging earthquakes that occurred beneath Tokyo include the 1855 Ansei Edo earthquake, the 1894 Meiji Tokyo earthquake, and the 1923 Kanto earthquake. Whereas the Kanto earthquake is known to have occurred at the top of the subducting Philippine Sea Plate, the other events are considered to have occurred in Tokyo bay, but their source depths are unknown. Many researchers have attempted to determine the source mechanisms of these earthquakes through analyses of patterns of seismic intensity distribution in the Kanto area, but the intensity pattern at the center of Tokyo would be considerably affected by the site amplification effect of the shallow, localized structure rather than be related directly to the source itself. In the present paper, we summarize the characteristics of strong ground motions and damage caused by the earthquakes. We then compare the pattern of intensities on local and regional scales with those of recent earthquakes occurring in Tokyo and corresponding computer simulations using heterogeneous crust and upper-mantle structure models below Tokyo to find referable source models for the Ansei Edo and Meiji Tokyo earthquakes.