芦山M_S7.0地震前的电磁异常信号  

Electromagnetic anomalies before the 2013 Lushan M_S7.0 earthquake

作　　者：马钦忠[1] 方国庆[1] 李伟[1] 周江南[1] 

机构地区：[1]上海市地震局,中国上海200062

出　　处：《地震学报》2013年第5期717-730,共14页Acta Seismologica Sinica

基　　金：地震科技星火计划(XH12016);上海市科委科研计划项目(12231202700)共同资助

摘　　要：对南北地震带18个地电场及电磁扰动观测台站进行了跟踪与研究,2013年4月20日四川芦山MS7.0地震前只有其中5个台站观测到了异常电磁信号.研究表明,地震前的这些异常信号时空分布非常不均匀.在时间上表现出震前电磁异常信号在出现的台站上不是同步的,且随着时间的推移有向震中方向迁移的趋势;在空间上体现在成都以北的台站都没有记录到震前电磁异常信号,主要出现在成都及其以南的一些台站.芦山MS7.0地震前地震电磁信号出现的最早时间是震前21天,其次是震前16天;临震时间则为震前5天、4天和1天.通过接地极注入地下的大电流以及以往的震例分析,认为仙女山台是又一个比较突出的电磁信号观测的敏感点.This paper studies the geoelectric field and electromagnetic disturbance observed at the eighteen stations laid out in the South-North Seismic Belt in China. Before the 20 April 2013 Lushan MS7.0 earthquake, only at the five stations were abnormal electromagnetic disturbance signals recorded. The study shows that the electromagnetic signals are distributed heterogeneously in space-time, and they do not appear synchronously at different stations, which migrate toward near the epicenter with time. In spatial distribution, the abnormal signals before the earthquake were recorded only at several stations to the south of Chengdu station （including Chengdu station）, but not recorded at the stations to the north of Chengdu. Before the Lushan MS7.0 earthquake the earliest lead time of the signals is 21 days, and then 16 days. Immediately before the event the lead times are 5 days, 4 days and 1 day, respectively. By studying the signals originated from grounding electrode 4 500 A current and some earthquake examples, Xiannüshan station is considered as a new sensitive site for the electromagnetic observation.

关 键 词：芦山地震 地电场 电磁扰动 信号识别 地震前兆 

分 类 号：P315.7[天文地球—地震学]