腾冲地震台地电阻率观测受金属管道干扰的判定分析

ANALYSIS ON EARTH RESISTIVITY OBSERVATION AT TENGCHONG SEISMIC STATION INFLUENCED BY METAL PIPELINE INTERFERENCE

腾冲地震台地电阻率采用四极对称装置观测,2016年11月15日开始,地电阻率东西向测值异常升高。通过对观测系统及外线路漏电情况检查,对观测仪器临时标定检查,结果显示观测系统运行正常,仪器工作正常;对观测布极区周围环境进行全面巡查,发现观测场地内东西测向东端一侧架设了一条金属自来水管道,为观测区内的新增干扰源,且地电阻率东西向测值异常出现的时间与金属管道架设时间基本同步。将金属管道更换为绝缘塑料管道后,测值恢复正常。分析认为,架设金属管道本质上改变了测区介质原有的导电结构,造成了人工电场分布的改变,从而导致地电阻率测值的变化,最终判定地电阻率东西向测值异常是由村民架设的金属自来水管道所致。

The earth resistivity of the Tengchong seismic platform was observed by a quadrupole symmetrical device.From november 15,2016,the ground resistivity EW direction measured abnormally.Through the inspection of the observation system and the leakage of the external line,the observation instrument is temporarily calibrated and checked.The result shows that the observation system is operating normally and the instrument works normally;the environment of the cloth pole area was inspected.It was found that a metal tap water pipe was installed on the east end of the EW direction in the observation site,which was a new interference source in the observation area,and the time when the earth resistivity EW was abnormally measured and the metal appeared.Pipeline erection time is basically synchronized.After replacing the metal pipe with the insulated plastic pipe,the measured value returns to normal.The analysis shows that the erecting of the metal pipe essentially changes the original conductive structure of the test medium,resulting in a change in the distribution of the artificial electric field,which led to the change of ground resistivity measurements.Finally,it is determined that the electrical resistivity EW to the measured abnormality is caused by the metal tap water pipe set up by the villagers.