文章基本信息

标题：Aftershock distribution of the 2004 Mid Niigata Prefecture Earthquake derived from a combined analysis of temporary online observations and permanent observations
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作者：Takuo Shibutani ; Yoshihisa Iio ; Satoshi Matsumoto 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2014
卷号：57
期号：6
页码：545-549
DOI：10.1186/BF03352590
出版社：Springer Verlag
摘要：The 2004 Mid Niigata Prefecture Earthquake (Mj = 6.8) occurred on 23 October 2004 in the northeastern part of the Niigata-Kobe Tectonic Zone where large contraction rates were observed. The mainshock was followed by an anomalously intense aftershock activity that included nine Mj ≥5.5 aftershocks. We deployed three temporary online seismic stations in the aftershock area from 27 October, combined data from the temporary stations with those from permanent stations located around the aftershock area, and determined the hypocenters of the mainshock and aftershocks with a joint hypocenter determination (JHD) technique. The resulting aftershock distribution showed that major events such as the mainshock, the largest aftershock (Mj = 6.5), the aftershock on 27 October (Mj = 6.1), etc. occurred on different fault planes that were located nearly parallel or perpendicular to each other. This might be due to heterogeneous structure in the source region. The strain energy was considered to have been enough accumulated on the individual fault planes. These features are probably a cause of the anomalous intensity of the aftershock activity.
关键词：The 2004 Mid Niigata Prefecture Earthquake; aftershock distribution; complexity of earthquake faults; temporary online aftershock observations