四0四多极距地电阻率年变化特征分析

采用2018年6月—2020年6月间ZD8MI地电阻率多极距观测系统在四0四台的观测数据，分析各测道的年变化特征，发现随着观测极距的不同各测道年变特征也不同；通过不同极距实验观测和年变化模拟分析表明，浅层电阻率的变化相对较大，而深层的变化相对较小，四0四台的年变化是由浅层介质电阻率随温度的季节性变化引起的，不同测道的年变形态受浅层不同深度介质电阻率的变化出现相位差异。因此利用多极距观测系统进行不同深度范围的地电阻率观测，对定量识别表层非震干扰显得尤为重要。

Annual variation characteristics of 404 multi-separationarray observation for earth resistivity

In this paper, the annual variation characteristics of each channel at 404 stations were analyzed by using the observation data of ZD8MI multi-separation array observation system from June 2018 to June 2020. It was found that the annual variation characteristics of each channel were different with the difference of observation pole distance. The experimental observation at different polar distances and the simulation analysis of annual change showed that the change of shallow resistivity is relatively large, while the change of deep resistivity is relatively small. The annual variation of 404 station is caused by the seasonal variation of shallow medium resistivity with temperature. The phase difference of annual variation form of different channels is caused by the variation of shallow medium resistivity at different depths. Therefore, the observation of earth resistivity at different depths by using the multi-separation array observation system is particularly important to quantitatively identify the surface non-seismic interference.