2022年四川泸定MS6.8地震前地下介质视电阻率变化特征及其机理分析  

Changes in apparent resistivity and its possible mechanisms before the Luding MS6.8 earthquake on September 5, 2022, Sichuan province, China

作　　者：解滔[1] 任越霞[2] 廖晓峰 何畅[2] 于晨 韩盈 卢军[1] XIE Tao;REN YueXia;LIAO XiaoFeng;HE Chang;YU Chen;HAN Ying;LU Jun(China Earthquake Networks Center,CEA,Beijing 100045,China;Sichuan Earthquake Agency,CEA,Chengdu 610041,China)

机构地区：[1]中国地震台网中心,北京100045 [2]四川省地震局,成都610041

出　　处：《地球物理学报》2023年第4期1428-1437,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42104075);北京市自然科学基金项目(8212045)联合资助。

摘　　要：2022年9月5日四川泸定县M_(S)6.8地震前四川地区运行有5个直流视电阻率连续观测站,其中红格、冕宁、江油和甘孜4个观测站在地震前出现了不同类型的中短期异常变化.本文结合岩石物理实验结果、岩土介质电阻率模型和断层虚位错模式对这4个观测站的异常变化与此次地震晚期孕育过程之间的联系进行了初步的分析,结果显示冕宁、江油和甘孜3个台站的视电阻率异常变化形态与地震前观测站所在区域相对的变形特征吻合,其中甘孜站为下降异常,位于此次地震孕育过程产生的挤压增强区域;冕宁和江油站为上升异常,位于相对膨胀区域;红格站为下降异常,但却位于相对膨胀区域,其观测数据的异常变化可能不仅仅受此次地震孕育过程的影响.There were five DC apparent resistivity stations in normal operation in Sichuan province before the Luding M_(S)6.8 earthquake occurred on September 5,2022.Four stations,i.e.,Hongge,Mianning,Jiangyou,and Garzê,showed different types of medium-short term anomalies before the earthquake.The relationship between these anomalies of the four stations and the late seismogenic process is preliminarily analyzed in this paper,based on the results from rock physics experiments,the resistivity model,and the fault virtual dislocation model.The results show that the anomalies recorded by stations of Mianning,Jiangyou,and Garzêare consistent with the relative deformation characteristics of the areas where the three stations are located.Apparent resistivity of Garzêstation showed decline changes and it was in an area of compression enhancement caused by the seimogenic process of this earthquake.Mianning and Jiangyou stations showed rise changes and they were in areas of relative extension.Hongge station showed decline changes,but it was in an area of relative extension.The anomalies recorded by Hongge station may not only be affected by the seimogenic process of the Luding M_(S)6.8 earthquake.

关 键 词：泸定M_(S)6.8地震 视电阻率 异常变化 电阻率模型 虚位错模式 震源机制解 

分 类 号：P315[天文地球—地震学]