地电场短临预报方法研究

根据1968年注意到震前电场变化与地下水位变化及断层活动有关的理论研究, 认为震前电场变化可能是过滤电势机制引起的。 鉴于地下流体压力分布不均匀、 断层阀作用及地下电流密度与流体流的耦合方程, 特别是由于电场异常显示出快急始慢衰减的特殊图型, 电场异常有的与废油井间歇自喷有关, 有的与流体压力增高有关, 故认为过滤电势作为电场前兆机制是合理的。 实验表明铅板电极可以用来记录电场前兆。 唐山和海城特大地震时和震前, 电场水平分量或垂直分量出现同震效应或震前异常。 利用地电场的异常变化预测地震在国内外均有成功的震例, 地电场法测量技术较为简便, 可做为地震短临预报的一种手段。

Study on geoelectric field method for short-term and impending earthquake prediction

Since 1968, it has been noted that preseismic variation in electrical field has something to do with both variation of water level in a well and the active fault, therefore it is inferred that observed anomalous electrical field is probably induced by a streaming potential mechanism. In view of inhomogeneous distribution of fluid pressure, fault-valve behavior and the coupled equations of the current density and fluid flow within the Earth′s crust, especially, the observed anomalies in electrical field showed a similar pattern of rapid starting and slow decay, some of these anomalies associated with episodical spouting from borehole or the increase of fluid pressure in wells, it is reasonable to consider that the source of precursory electrical field anomalies is the streaming potential mechanism. Experimental results show that lead electrodes can record precursor in electrical field. Anomalies of either horizontal and/or vertical component in electrical field are observed during and before both the M7.8 Tangshan earthquake of 1976 and the M7.3 Haicheng earthquake of 1975. There are cases showing some strong earthquakes were predicted through analysis of geoelectrical field data both at home and abroad. The geoelectrical field method, which is easy to measure, can be applied in a short-term and impending earthquake prediction.