2020年云南巧家MS5.0地震震源机制解与发震断层归属  

The focal mechanism solution and seismogenic fault of the 2020 Qiaojia MS5.0 earthquake in Yunnan

作　　者：李文涛 党文杰 金明培[1,2] 程旭东 曹舸斌 李勇[1] LI Wentao;DANG Wenjie;JIN Mingpei;CHEN Xudong;CAO Gebin;LI Yong(Yunnan Earthquake Agency,Kunming 650224,China;Yunnan University,Kunming 650504,China)

机构地区：[1]云南省地震局,中国昆明650224 [2]云南大学,中国昆明650504

出　　处：《地震地磁观测与研究》2020年第3期184-192,共9页Seismological and Geomagnetic Observation and Research

摘　　要：2020年5月18日云南巧家发生MS 5.0地震,基于国家和区域数字地震台网14个宽频带台的波形资料,利用CAP方法进行反演,得到其震源机制:节面Ⅰ:走向175°,倾角70°,滑动角-18°;节面Ⅱ:走向271°,倾角73°,滑动角-159°;震源矩心深度约9 km。结合主震震中位置、余震序列空间分布、地震烈度等值线图及区域地质背景,讨论此次巧家MS 5.0地震的发震断层,初步判定,包谷垴—小河断裂的雁列状次级隐伏构造走向SSE,具高角度左旋走滑性质,可能为其发震断层。Based on the broadband seismic records at 14 stations of national and regional digital seismic networks, we obtained the focal depth and focal mechanism solution of the MS 5.0 earthquake in Qiaojia, Yunnan, on May 18, 2020, with the Cut and Paste(CAP) method. Our result shows that the best double couple solution for the earthquake is 175°, 70°, and-18° for the strike, dip, and rake angles respectively, the other nodal plane is 271°, 73°and-159°, and the depth of center is 9 km. Further, we analyzed the rupture characteristics and seismogenic structures of the earthquake, combining with the earthquake epicenters, aftershock sequences, seismic intensity, and regional geologic structure background. We infer that the MS 5.0 earthquake occurred on the SSE striking secondary concealed structure of the Baogunao-Xiaohe fault. It is an SSE strike high-angle left-handed strike-slip fault.

关 键 词：震源机制解 云南巧家地震 CAP方法 发震构造 

分 类 号：P315.33[天文地球—地震学]