2021年青海玛多7.4级地震前应变演化特征分析  

Analysis of Strain Evolution Characteristics before the 2021 Maduo 7.4 Earthquake in Qinghai

作　　者：韩帅帅 谭凯[1,2] 鲁小飞 张彩红 李琦[1,2] HAN Shuaishuai;TAN Kai;LU Xiaofei;ZHANG Caihong;LI Qi(Institute of Seismology,CEA,40 Hongshance Road,Wuhan 430071,China;Key Laboratory of Earthquake Geodesy,CEA,40 Hongshance Road,Wuhan 430071,China)

机构地区：[1]中国地震局地震研究所,武汉市430071 [2]中国地震局地震大地测量重点实验室,武汉市430071

出　　处：《大地测量与地球动力学》2023年第6期641-645,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局武汉地球观测研究所科技发展基金(302021-21)。

摘　　要：计算1999~2016年、2017~2020年青海玛多及其周边地区GNSS速度场,同时采用连续滑移回归方法获取该地区震前面膨胀率、主应变率及最大剪切应变率,分析其动态演变特征。结果表明:1)震前该地区构造运动并未出现明显调整;2)震前震中附近区域面膨胀率下降,说明震中附近区域应变能累积降低;3)震前震中附近区域最大剪切应变率和主应变率有所增强,说明震中附近出现应力调整现象,剪切作用增强。We calculate the GNSS velocity field of Maduo and its surrounding areas in Qinghai during 1999-2016 and 2017-2020,and using continuous slip regression method obtain the surface expansion,principal strain and maximum shear strain rates in this area before the Maduo earthquake.We analyze their dynamic evolution characteristics.The results show that:1)There is no obvious adjustment of tectonic movement in this area before the earthquake;2)Before the earthquake,the surface expansion rate near the epicenter decreased,indicating that the accumulation of strain energy near the epicenter decreased;3)Before the earthquake,the maximum shear strain rate and the principal strain rate near the epicenter increased,indicating that the stress adjustment phenomenon occurred near the epicenter and the shear effect is enhanced.

关 键 词：GNSS速度场 地壳形变 应变率场 玛多7.4级地震 

分 类 号：P315[天文地球—地震学] P227[天文地球—固体地球物理学]