大同地电阻率NS测向异常分析

Anomaly analysis of earth resistivity in NS direction at Datong Seismic Station

2014年大同地震台地电阻率NS测向出现年变畸变现象,经现场调查,发现测区有铁丝网干扰。利用NS测向电测深曲线,以水平层状模型反演测区电性结构,计算各层介质影响系数,结果发现,浅层介质影响系数为正,合理解释了大同地电阻率NS测向"夏低冬高"的年变现象。在此基础上,应用有限元数值分析和三维影响系数分布,判定测区内铁丝网对地电阻率观测的影响,分析认为,当前存在的趋势异常变化为地电阻率干扰。

The annual aberration of resistivity from Datong Seismic Station in NS direction is detected since 2014. After investigation, we found that the surrounding environment changes with barbed wire. Based on the electrical sounding data of earth resistivity of NS direction, the electrical structure of the measuring region are inversed on horizontal layered model. The sensitivity coefficient of each layer medium in under NS direction is calculated. Annual variation of ＂Low in summer and high in winter＂ of each resistivity is interpreted. On the base, we qualitatively analyze the disturbing effects caused by the barbed wire using numerical analysis three dimensional sensitivity coefficient. The result show that the change isn＇t anomaly.