Fault system of the 2004 Mid Niigata Prefecture Earthquake and its aftershocks
Fault system of the 2004 Mid Niigata Prefecture Earthquake and its aftershocks
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DOI：
10.1007/s10346-005-0050-8
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发表时间：
2005-05
期刊：
影响因子：
6.7
通讯作者：
N. Hirata;Hiroshi P. Sato;S. Sakai;A. Kato;E. Kurashimo
中科院分区：
文献类型：
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作者：
N. Hirata;Hiroshi P. Sato;S. Sakai;A. Kato;E. Kurashimo
2004年日本中部新泻县6.8级地震后第二天部署的地震台网记录的数据被用来确定主震和主要余震的主要震源断层。利用这一高分辨率地震资料，识别出三条主要震源断层：两条平行的西倾断层相距5公里，另一条向东倾斜，方向垂直于西倾断层。分析还表明，地表观测到的地震速度的横向变化延伸到15公里深，包围了主震的震源区。地壳的这种强烈的非均质性，与该地区复杂的地质和构造演化有关，被认为是2004年新泻地震后发生显著余震活动的原因。
Data recorded by a seismic network deployed the day after the 2004 Mid Niigata Prefecture Earthquake (M6.8) in central Japan are used to determine the major source faults responsible for the mainshock and major aftershocks. Using this high-resolution seismic data, three major source faults are identified: two parallel faults dipping steeply to the west located 5 km apart, and the other dipping eastward and oriented perpendicular to the west-dipping faults. The analysis also reveals that the lateral variation in seismic velocity observed at the surface extends to a depth of 15 km, encompassing the source area of the mainshock. This strong heterogeneity of the crust, related to the complex geological and tectonic evolution of the area, is considered to be responsible for the prominent aftershock activity following the 2004 Niigata event.