The 2015 Gorkha Earthquake: Earthquake Reflection Imaging of the Source Fault and Connecting Seismic Structure With Fault Slip Behavior
The 2015 Gorkha Earthquake: Earthquake Reflection Imaging of the Source Fault and Connecting Seismic Structure With Fault Slip Behavior
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DOI：
10.1029/2018gl081197
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发表时间：
2019-03
影响因子：
5.2
通讯作者：
E. Kurashimo;Hiroshi P. Sato;S. Sakai;N. Hirata;A. Gajurel;D. P. Adhikari;K. Subedi;H. Yagi;B. Upreti
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文献类型：
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作者：
E. Kurashimo;Hiroshi P. Sato;S. Sakai;N. Hirata;A. Gajurel;D. P. Adhikari;K. Subedi;H. Yagi;B. Upreti
对2015年廓尔喀地震中心震源区进行了地震台阵观测，以研究余震分布和地壳结构。加德满都附近的大多数余震位于喜马拉雅主逆冲断层（MHT）上方。地震反射成像揭示了 MHT 的几何形状，其深度约为 10 公里，距主锋面逆冲断层 75 公里。我们发现MHT周围15公里深度以上的三个地震速度变异区域：（1）高Vp区，MHT的倾角从5°变为13°，与同震滑移的局部最大值一致；（2）低Vp区，显示同震滑移较少；（3）高Vp区，其中同震滑移进一步减少，但发生后滑。这些滑动行为的差异可能表明断层上摩擦特性的变化，这反映在速度结构的异质性上。
A seismic array observation across the central focal area of the 2015 Gorkha earthquake was conducted to investigate aftershock distribution and crustal structure. Most aftershocks near Kathmandu were located above the Main Himalayan Thrust (MHT). Earthquake reflection imaging revealed the geometry of the MHT, which lies at ~10‐km depth at 75 km away from the Main Frontal Thrust. We found three areas of seismic velocity variability around the MHT above 15 km depth: (1) a high‐Vp zone where the MHT changes its dip angle from 5° to 13°, coinciding with a local maximum in coseismic slip, (2) a low‐Vp zone showing less coseismic slip, and (3) a high‐Vp zone where coseismic slip decreased further but afterslip occurred. These differences in slip behavior may indicate changes in frictional properties on the fault, which are reflected in the heterogeneity of the velocity structure.