地电阻率长趋势变化及其预测意义

摘要

The trend variations in the earth-resistivity over one year scale are observed in large quantities.This trend variation is regional and synchronous.In order to study this phenomenon,this paper analyzes the reasons for the trend variation of resistivity from the view points of the relationship between water level and ground resistivity,and between ground level and resistivity,as well as the earth tide phenomenon of ground resistivity through the theory,experiment and example analysis.It is considered that the trend variation is independent of the observation system or the water level (non-tectonic water level),but relate to structural change.The rising and falling trend respectively reflect the compressional and extensional variation of stress field around.Furthermore,taking the stations Gaoyou and Chengdu as examples,the characteristics of the resistivity trend are analyzed based on the relationship between the surrounding earthquakes and the resistivity.The result shows that the uptrend turning has short-term predictive implication,which can provide a reference for the research on the long-term trend of resistivity.The future earthquake prediction needs to be integrated with the observation results of each station,which can effectively determine the direction and the relative amplitude of regional stress field,so as to give some significant results of earthquake precursor and prediction.%为了深入研究地电阻率1年尺度以上趋势变化的区域性和同步性,本文从地电阻率与水位、水准的关系以及地电阻率固体潮现象的角度,通过理论、实验、实例分析了地电阻率趋势变化产生的原因.分析结果显示,地电阻率趋势变化与观测系统或水位(非构造水位)无关,而与周围构造变化有关,且趋势上升和下降分别反映了周围应力场的压性和张性变化.在此基础上,以高邮台和成都台为例,从地电阻率与周围地震的关系分析了地电阻率趋势变化的场兆特征,结果表明地电阻率在上升趋势转折时更具有短期的预测意义.本文结果可以为研究地电阻率的长期趋势变化现象提供参考;未来地震的预测需在综合各台站观测结果的基础上才能有效地判定区域应力场的方向和相对幅度,从而给出有意义的地震前兆预测结果.