2020年7月12日古冶M_(S) 5.1地震前北京地电阻率异常分析  

Analysis of apparent resistivity anomalies in Beijing before the Guye M_(S) 5.1 earthquake on June 12,2020

作　　者：王丽红[1] 王同利[1] 武敏捷[1] 李菊珍[1] 岳晓媛[1] 李红[1] WANG Lihong;WANG Tongli;WU Minjie;LI Juzhen;YUE Xiaoyuan;LI Hong(Beijing Earthquake Agency,Beijing 100080,China)

机构地区：[1]北京市地震局,北京100080

出　　处：《地震地磁观测与研究》2023年第3期87-94,共8页Seismological and Geomagnetic Observation and Research

基　　金：北京市地震局科技项目(项目编号:BJWC—2022011)。

摘　　要：使用曲线形态法和归一化速率法,分析了2020年7月12日古冶地震前北京地区地电阻率异常变化特征。通州、延庆和平谷台地电阻率归一化速率异常与本次地震均有较好地对应,发震时间均为异常出现后半年内。通州和延庆台1—2年尺度月均值曲线形态异常,半年尺度归一化速率超阈值异常,符合中长期孕震和中短期加速变化后发震的发震机理。平谷台月均值曲线无明显异常,归一化速率异常明显,表明使用归一化速率可较好识别和提取曲线的弱异常。延庆和平谷台震前地电阻率归一化速率异常存在各向异性,且符合地电阻率受震源主压应力方向影响的特征。平谷台对唐山地区地震的映震能力较弱,通州、延庆台的映震能力较强。By using the curve shape method and the normalized variation rate method,the variation characteristics of the apparent resistivity anomaly in Beijing before the Guye earthquake on July 12,2020,are analyzed.The normalized rate anomalies of apparent resistivity in Tongzhou,Yanqing,and Pinggu seismic stations are well correlated with the earthquake,who seoccurrence time is within half a year after the anomalies appear.The shape anomalies of the monthly mean curve on a scale of 1-2 years and the exceeding threshold anomalies of the normalized variation rate method on a scale of 6 months are consistent with the seismogenic mechanism of mid-longterm seismogenic and medium-shortterm accelerated changes in Tongzhou and Yanqing seismic stations.There is no obvious anomaly in the shape of the monthly mean curve of Pinggu seismic station,but the anomaly in the normalized variation rate is significant,which indicates that using the normalized variation rate method can better identify and extract the weak anomalies in the curve shape.The anomaliesof the normalized variation rate method of apparent resistivity are anisotropy in Yanqing and Pinggu seismic stations before the Guye earthquake,which accord with the characteristic that the apparent resistivity is influenced by the principal compressive stress direction of the focal mechanism solutions.The ability of the Pinggu station to reflect earthquakes in the Tangshan region is weak,while the ability of the Tongzhou and Yanqing stations is strong.

关 键 词：地电阻率 归一化速率法 曲线形态法 古冶地震 

分 类 号：P315.722[天文地球—地震学]