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Title:: Determination of the Focal Mechanism and Focal Depth of the Xiahe, Gansu M_S5.7 Earthquake in 2019

作者:: 袁伏全¹; 黄浩¹; 蔡丽雯¹; 李启雷¹; 赵燕杰¹; 刘兴盛²; (1.青海省地震局,青海西宁810001; 2.青海省应急管理厅信息中心,青海西宁810001)

Author(s):: YUAN Fuquan¹; HUANG Hao¹; CAI Liwen¹; LI Qilei¹; ZHAO Yanjie¹; LIU Xingsheng²; (1.Qinghai Earthquake Agency,Xining 810001,Qinghai,China;2.Emergency Management Department of Qinghai Province,Xining 810001,Qinghai,China)

Keywords:: the Xiahe earthquake; CAP method; focal depth; time-reversal imaging technique

摘要:: 为了准确测定2019年甘肃夏河M_S5.7地震的震源深度,利用青海、甘肃和四川数字地震台网宽频带数字地震波形资料,采用CAP方法和区域速度模型反演夏河地震震源机制,并采用逆时成像技术进一步约束了此次地震的震源深度。结果表明,夏河M_S5.7地震是一次逆冲兼走滑型地震,震源深度为5.4 km; 基于遥感解译和野外调查新发现的夏河断裂可能是甘肃夏河5.7级地震的发震构造,即节面Ⅰ(走向305°/倾角52°/滑动角50°)为发震断层面。

Abstract:: In order to accurately determine the focal depth of the Xiahe,Gansu M_S5.7 earthquake,we used the broadband waveforms from Qinghai Seismic Networks,Gansu Seismic Networks and Sichuan Seismic Networks to invert the focal mechanism of this earthquake on the basis of Cut-and-Paste(CAP)method and the regional velocity model.We further delimited the earthquake's depth by the time-reversal imaging technique.We find that this earthquake is a thrust and strike slip one,and its focal depth is about 5 km.And its seismogenic fault is the Xiahe fault,which is newly discovered by remote sensing interpretation and field investigation,i.e.the planeⅠ(strike 305°/dips 52°/rake 50°)could be the seismogenic fault.