Imaging the source region of the 2004 mid‐Niigata prefecture earthquake and the evolution of a seismogenic thrust‐related fold
Imaging the source region of the 2004 mid‐Niigata prefecture earthquake and the evolution of a seismogenic thrust‐related fold
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DOI：
10.1029/2005gl022366
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发表时间：
2005-04
影响因子：
5.2
通讯作者：
A. Kato;E. Kurashimo;N. Hirata;S. Sakai;T. Iwasaki;T. Kanazawa
中科院分区：
文献类型：
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作者：
A. Kato;E. Kurashimo;N. Hirata;S. Sakai;T. Iwasaki;T. Kanazawa
通过使用双差断层扫描反演 716 次余震的到达时间，阐明了 2004 年新泻县中部地震的速度结构和准确的余震分布。主震发生后46小时内，立即在震源区及周边部署了14个时态地震台站。上盘地震速度低于下盘，速度对比延伸至约10 km的深度。与主震相关的余震分布在低速结构和高速结构之间的清晰边界周围。据解释，新泻县中部地震的主震断层面自3.5Ma开始地壳缩短以来，作为逆断层重新活动。日本海岸线的地壳拉伸或缩短形成了低速带等复杂结构，有可能控制震源区周围的地震活动。
The velocity structure and accurate aftershock distributions of the 2004 mid‐Niigata prefecture earthquake are elucidated by inverting the arrival times from 716 aftershocks using double‐difference tomography. Fourteen temporal seismic stations were immediately deployed in and around the source region within 46 h of the occurrence of mainshock. The seismic velocities in a hanging wall are lower than those in a footwall, and the velocity contrast extends to a depth of approximately 10 km. The aftershocks associated with the mainshock are distributed around the clear boundary between the low and high velocity structures. It is interpreted that the mainshock fault plane of the mid‐Niigata prefecture earthquake was reactivated as a reverse fault since the crustal shortening initiated at 3.5 Ma. Crustal stretching or shortening along the Japan coastline has created complex structures such as low velocity zones, which can potentially control the seismic activities around the source region.