2008年汶川MS8.0地震前后地电阻率时空变化
王同利1,崔博闻1,王丽红1,颜晓晔2,李菊珍1

(1.北京市地震局,北京 100080; 2.四川省地震局,四川 成都 610000)

汶川MS8.0地震; 地电阻率; 时序分析; 空间分布; 归一化速率变化方法

Temporal and Spatial Evolution of the Apparent Resistivity before and after the 2008 Wenchuan MS8.0 Earthquake
WANG Tongli1,CUI Bowen1,WANG Lihong1,YAN Xiaoye2,LI Juzhen1

(1.Beijing Earthquake Agency,Beijing 100080,China)(2.Sichuan Earthquake Agency,Chengdu 610000,Sichuan,China)

the Wenchuan MS8.0 earthquake; apparent resistivity; time sequential analysis; spatial distribution; the Normalized Variation Rate method

DOI: 10.20015/j.cnki.ISSN1000-0666.2022.0008

备注

采用归一化速率变化方法对2008年汶川MS8.0地震震中周边19个定点台站观测到的地电阻率的时空变化过程进行了计算分析。时序分析结果显示:在汶川地震前,震中周边多个地电阻率台站准同步地出现了中短期前兆异常; 空间分布过程显示,地震孕震过程中地电阻率在震中区域有负异常丛集和由远及近的迁移现象,负异常丛集呈象限分布,长轴方向与震源机制解主压力方向基本吻合,且受孕震断裂、台站位置、观测装置布设方向等的影响。
In this paper,the Normalized Variation Rate method is used to analyze the sequential and spatial variation of the apparent resistivity observed by 19 stations around the Wenchuan MS8.0 earthquake.The sequential analysis shows that some of the earthquake stations had quasi-synchronously recorded the short- and medium-term precursory anomalies of the apparent resistivity before the Wenchuan earthquake.The spatial analysis shows that in the epicentral region,the negative anomalies of the apparent resistivity had been featured with a strip distribution and with a migration from far to near before the earthquake.The cluster of the anomalies displayed a quadrant pattern,whose long axis was consistent with the direction of principal compressive stress of the focal mechanism solution.The seismogenic fault,the station location,and the layout direction of the observational instruments also influenced the distribution direction of the long axis of the precursory anomalies.