study on crustal velocity structure beneath kouquan fault and adjacent area |
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Authors: | WANG Xia SONG Mei-qin WANG Liang LI Hong-wei WU Hao-yu LUO Yong |
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Affiliation: | 1. Earthquake Administration of Shanxi Province, Taiyuan 030021, China;2. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China;3. Earthquake Administration of Liaoning Province, Shenyang 110034, China |
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Abstract: | Through simultaneous inversion of earthquake hypocenters and velocity structure, we obtained the precise locations of earthquakes occurring from 1981 to 2013 in northern Shanxi and the 3D velocity structure, and analyzed emphatically the Kouquan Fault. The result of earthquake relocation shows that earthquakes are concentrated in the central-north segment of Kouquan Fault and the distribution is sparse towards both south and north end of the fault, which indicates that the strong activity is in the central-north segment of Kouquan Fault and the seismicity becomes weaker towards both ends. The result of velocity structure shows that the earthquake concentrated segment of Kouquan Fault is on the side of relative low-velocity area in the high-velocity body, and the south segment of Kouquan Fault is the continuous low velocity. We can recognize the velocity gradient zone from the obvious depression near the Kouquan Fault, which, as we preliminarily speculate, may be the evidence of the presence of Kouquan Fault(or basement detachment)at the deep part. The parallel velocity profile (velocity ratio profile) to Kouquan Fault shows that the earthquake cluster in the central-north segment of Kouquan Fault is located in the abrupt change zone from high to low velocity(from high to low velocity ratio). |
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Keywords: | velocity structure simultaneous inversion Kouquan Fault |
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