基于震例的地震电磁异常特征研究

Characteristics of Electromagnetic Anomalies based on Earthquake Cases in China

依据《中国震例》(1966—2012年)中中国大陆发生的252次M_S≥5.0震例资料,将其中与电磁异常相关的135个震例中的457项电磁异常进行收集整理,建立较为完备的中国大陆电磁异常库。在此基础上,对中国大陆电磁异常的测项种类、区域差异、异常分类、敏感点进行统计分析,并对异常测项、异常特征与主震震级的关系进行了探讨。研究结果表明,电磁异常在大华北、南北带中南段、青藏高原北部地区有较好的映震效果;地电异常的中短期性质更突出,电磁扰动则主要为临震异常;地磁日变畸变等测项具有显著的指标意义,可为震情判定提供重要参考。

Based on Earthquake Cases in China,which introduced 252earthquake（MS≥5.0）cases occurred from 1966—2012in China's Mainland,among which,135 earthquake cases are related to the electromagnetic anomaly and there are 457 electromagnetic anomalies,based on which,a relatively complete electromagnetic anomaly library is established.On this basis,we carry out statistical analyses of item types,regional differences,classification and sensitive sites of electromagnetic anomalies in China's Mainland,and a detailed discussion of the relations between the anomaly items,anomaly characteristics and the mainshock magnitude.The results show that electromagnetic anomalies work well in reflecting earthquakes in the areas of great north China,the middle and southern segments of the South-North Seismic Belt,the northern region of Qinghai-Tibet plateau.Most of geoelectric anomalies are intermediate and short-term anomalies,and electromagnetic disturbance anomalies are mainly impending anomalies;Some electromagnetic items such as distortion of the geomagnetic diurnal variation has remarkable meaning as a forecast index and provide important reference for earthquake monitoring.