苍山5.2级地震前临沂台深井地电异常

DEEP WELL GEOELECTRICITY ANOMALY IN LINYI STATION BEFORE THE CANGSHAN M S 5.2 EARTHQUAKE

对苍山５．２级地震前距震中２３ｋｍ的临沂台深井地电观测资料进行了分析．结果表明，震前该台电阻率和自然电位出现了长达５年的与地震活动性异常同步的趋势异常．震前６个月电阻率出现下降异常．震前２４天自然电位和电阻率同时急剧下降。

Through analysis on deep well geoelectricity data of Linyi station which is 23 km away from the epicentre of the Cangshan M S 5.2 earthquake,it is shown that before the earthquake,the background tendency anomalies of the deep well resistivity and natural geoelectric potential appeared synchronously with the seismicity anomaly for 5 years.The descending tendency anomaly of deep well resistivity occurred six months before the earthquake.The natural geoelectric potential and resistivity reduced rapidly 24 days before the earthquake,and then rose again abruptly after the earthquake.