著者

村瀬 圭

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.55, no.1, pp.11-18, 2002-07-25 (Released:2010-03-11)

参考文献数

28

被引用文献数

1

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The author investigated fractal structure of hypocentral distributions before the 2000 Tottoriken Seibu earthquake (MJ=7.3), by estimating temporal changes in the spatial fractal dimension D of the hypocenter distributions, and comparing these results with the seismic activity in and around the focal region. The correlation integral method and the running time-window technique were applied to the D-value calculation for the JMA Earthquake Catalogue data during the period of January 1983 -February 2001. The results obtained are summarized as follows; (1) The D-value decreased drastically prior to the main shock in and around the focal region. The precursory durations are estimated as 1-3 years, which may be different with different sizes of the time-window. (2) The D-value decrease must be caused by hypocenter clusterings, or unusual seismic activity, which occurred over the wide area in and around the focal region. (3) Consequently, temporal variations in the D-values associated with a large earthquake may be effective as a precursor to the earthquake.