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讨论了有效电阻率椭圆及各向异性奇象现象．对任意夹角三道测线或相互垂直二道测线并增测横向有效电阻率的二种情况，分别给出了定量计算地电阻率各向异性参量的方法，即求最小电阻率ρ１主轴方位角α，平均电阻率（ρ１ρ３）１２，（ρ２ρ３）１２及各向异性系数λ＝（ρ２／ρ１）１２的方法．作为实例对大同台的资料进行了处理，结合原地电阻率剪切实验结果，得出在１９８９年１０月１９日大同６．１级地震前后，震中附近大同、阳原二台ＮＥ向地电阻率异常上升，ＮＷ道异常下降系介质受到纯剪切所致．其最大主应力方向为北东，与地震断层走向夹锐角．断层面上的剪应力较大，正应力甚小，断层易于滑动，故地震的震级并不特别大．震前与震时介质应力状态相同，故地电阻率前兆与同震变化符号一致
The effective resistivity ellipse and anisotropic odd phenomenon are discussed. For two kinds of cases where there are three measuring lines at any angle or two measuring lines perpendicular to each other and the lateral effective resistivity is measured, the methods of quantitatively calculating the resistivity anisotropy parameters are respectively given, namely, finding the minimum resistivity ρ1 spindle Azimuth angle α, average resistivity ρ1ρ3 12, ρ2ρ3 12, and anisotropy coefficient λ = (ρ2 / ρ1) 12. As an example, Datongtai data were processed. Based on the in-situ resistivity shear test results, it was found that before and after the Datong 6.1 earthquake on October 19, 1989, Datong and Yangyuan stations near NEO NE Abnormal increase in resistivity, NW channel anomalies caused by the system due to pure shear. The direction of its maximum principal stress is north east, and the strike of the seismic fault is acute. The shear stress on the fault plane is large, the normal stress is very small and the fault is easy to slip, so the earthquake magnitude is not particularly large. Pre-earthquake and earthquake stress state is the same, so the earth’s resistivity precursors and coseismic changes consistent with the symbol