On August 8,2017,an Mw 6.5 earthquake occurred in Jiuzhaigou County,Sichuan Province,China,on the eastern margin of the Qinghai-Tibet Plateau.This study investigates the coseismic deformation field and fault model with ascending and descending Sentinel-1 synthetic aperture radar(SAR)images,aftershock distribution,and elastic half-space dislocation model.The regional fault slip pattern is then quantita-tively examined using the boundary element method.The results show that the ascending and descending interferometric synthetic aperture radar(InSAR)coseismic deformation fields display an overall NNW-SSE trend,with more significant deformation on the southwest side of the fault.The coseismic fault geometry is divided into NW and SE sub-faults with strikes of 162.1° and 149.3°,respectively.The coseismic fault slip is dominated by a left-lateral strike-slip movement with an average rake of-2.31°,mainly occurring at a depth of 0-13.04 km with a shape of an approximately inverted triangle.The fault slip features two peak slip zones,with a maximum of 1.39 m.The total seismic moment is 6.34×1018 N·m(Mw 6.47).The boundary element calculation quantitatively indicates that the regional fault slip pattern may be mainly attributable to the changing strike and dip.The strike changes from NNW-SSE to nearly NS direction,and the dip gradually decreases from the Jiuzhaigou earthquake fault in the north to the Huya fault in the south.With these characteristics,the Huya and the Jiuzhaigou earthquake faults form the eastern boundary of the Minshan uplift zone and accommodate the accumulated deformation.

Yang Liu;Yangmao Wen;Zhicai Li;Ying Peng;Caijun Xu

School of Geodesy and Geomatics,Wuhan University,Wuhan 430079,China;Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University,Wuhan 430079,China;Key Laboratory of Geophysical Geodesy,Ministry of Natural Resources,Wuhan University,Wuhan 430079,China;Department of Geodesy,National Geomatics Center of China,Beijing 100830,China;School of Geoscience and Surveying Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Changguang Satellite Technology Co.,Ltd,Changchun 130102,China

大地测量与地球动力学（英文版）

[1]Yang Liu;Yangmao Wen;Zhicai Li;Ying Peng;Caijun Xu-.Coseismic fault model of the 2017 Mw 6.5 Jiuzhaigou earthquake and implications for the regional fault slip pattern)[J].大地测量与地球动力学（英文版）,2022(02):104-113

Huya,Minshan

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