2021年云南漾濞M_(s)6.4地震震前地壳形变特征研究  

Characterstics of Tectonic Deformation before the 2021 Yangbi M_(s)6.4 Earthquake in Yunnan

作　　者：邹芳 孟国杰[2] 苏小宁 吴伟伟[2] 赵倩[2] 佘雅文[2] Thant Myo ZOU Fang;MENG Guo-jie;SU Xiao-ning;WU Wei-wei;ZHAO Qian;SHE Ya-wen;Thant Myo(School of Civil and Transportation Engineering Guangdong University of Technology,Guangzhou 510006,China;State Key Laboratory of Earthquake Forecasting,Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Lanzhou Jiaotong University Faculty of Geomatics,Lanzhou 730070,China;Department of Geology,University of Yangon,,Yangon 11041,Myanmar)

机构地区：[1]广东工业大学土木与交通工程学院,广东广州510006 [2]中国地震局地震预测研究所(地震预测重点实验室),北京100036 [3]兰州交通大学测绘与地理信息学院,甘肃兰州730070 [4]缅甸仰光大学地质系,缅甸仰光11041

出　　处：《地震》2022年第3期21-36,共16页Earthquake

基　　金：国家重点研发计划项目(2019YFE0108900,SQ2019YFE010563);国家自然科学基金面上项目(41874024);中国地震局地震预测研究所基本科研业务费专项(CEAIEF20220404);亚洲区域专项合作专项(999223601)

摘　　要：2021年5月云南大理州漾濞发生一系列中强地震,其主震达到M_(s)6.4,主震震中位于滇南块体内部的维西—乔后—巍山断裂西南侧,发震断层可能为维西—乔后—巍山断裂的次级分支断裂,地表走向约为135°.本文收集1998年以来的震中周边GPS测站观测数据,研究了此次地震序列震前区域地壳的水平形变特征及其与此次地震的关系.结合构造分析认为,漾濞地震发生在GPS测站水平运动速度陡变区域,该区域地壳水平运动受阻;震中区域应变积累明显,处于面应变率高值区,且为最大剪应变率的高低值转换区,符合易发地震区域特性.震中及其邻区的孕震环境以右旋剪切为主,兼具东西向拉张作用.In May 2021,a series of moderate earthquakes occurred in Yangbi,Yunnan Province,which seriously threatened the safety of people's lives and property.The epicenter of Yangbi M_(s)6.4 earthquake is located near the Weixi—Qiaohou—Weishan fault in the South Yunnan block.The seismogenic fault is a newly discovered fault with a strike of 135°.Based on GPS observation data from 1998 to 2020,the long-term crustal movement velocity field in the study area is obtained,and the horizontal deformation background characteristics of the regional crust before these strong earthquakes in Yangbi are studied,as well as its relationship with the occurrence of earthquakes.Combined with the structural analysis,it is considered that the Yangbi earthquake occurred in the area where GPS horizontal velocity steeply change.Here the horizontal crustal movement was blocked and the strain accumulation is obvious with the high value area of surface strain rate and maximum shear strain rate.The seismogenic faults in this area are mainly affected by dextral shear and E-W extension.

关 键 词：2021年漾濞M_(s)6.4地震 滇南地区 GPS基线 地壳形变 

分 类 号：P315.7[天文地球—地震学]