地电场观测及强震前大地电位异常特征

THE OBSERVATIONS OF ELECTROTELLURIC FIELD AND ANOMALY CHARACTERS OF GEODETIC POTENTIAL BEFORE STRONG EARTHQUAKES

摘要:

通过平行方位相关分析、纯异常矢量比值和功率谱分析、P_c地电脉动、地电暴湾扰等多种方法论证了岱山中学地电场的短周期(小于4d)变化属于大地电位变化,该观测点是观测大地电位变化的敏感点。同时还分析了澜沧、巴塘等强震前的大地电位异常特征。这些异常变化受周期为10~30s的超低频电磁幅射调制,大地电位基值发生几个mV的短暂变化,异常持续时间为10~75min,其超前时间为8.8~32.5h。

Abstract:

It is considered that the shost-period variations of electro telluric field at Daishan middle school station belong to the geodetic potential through the analyses of parallel direction correlation, the pure anomaly vector ratio, P_C electrotelluric pulsation, geoelectric bay, etc. The station is highly sensitive to geodetic potential change. In addition, the characters of geodetic potential anomaly before the strong earthquakes occurring in Lancang, Batang, etc. are analyzed. These anomaly variations affected by the ultra-low frequency electromagnetic radiation occurred within 8.8 -32.5 hours before earthquakes and lasted the time from 20 min to 75 min.