基于褶积滤波的山丹地电阻率归一化速率异常特征分析

Analysis of the Abnormal Characteristics of Shandan Resistivity Normalization Rate Based on Convolution Filtering

利用褶积滤波法对山丹地电阻率进行去除降雨校正处理,再分别对原始数据和去降雨后数据在进行归一化月速率分析前作不同处理方式组合的结果进行映震效能统计,从而选出归一化速率分析前数据最优处理方式。结果显示,NS测道适用于去倾、去周期处理,EW测道和NW测道均适用于去周期处理,且去除降雨后各测道映震效能均优于去降雨前,说明降雨对山丹地电阻率异常提取有较大干扰。由于2022年祁连山地震带表现空前活跃,至8月逐渐恢复平静,因此选择2014~2022-08祁连山地震带及其附近中强地震活动前山丹地电阻率表现出的速率超限异常总结映震指标,利用2022-08~12山丹地电阻率的速率超限异常对逐渐平静的祁连山地震带地震危险性进行预测,分析山丹观测站附近地震活动水平是否真的降低,结果显示,山丹地电阻率观测值仍然存在速率超限异常,说明祁连山地震带的地震危险性仍然存在,地震活动水平并未减弱。

We use the convolution filtering method to eliminate rainfall correction processing for the resistivity of Shandan ground,and then carry out seismic response efficiency statistics on the original data and the data after rainfall removal respectively through the combination of different processing methods before the normalized monthly rate analysis,so as to select the optimal data processing method before the normalized rate analysis.The results show that the NS channel is suitable for decanting and deperiodic processing.Both EW and NW channels are suitable for deperiodic processing,and the seismic performance of each channel after the removal of rainfall is better than that before,indicating that rainfall has a great interference effect on the extraction of resistivity anomalies of Shandan station.Since the Qilian mountain seismic zone showed an unprecedented level of activity in 2022 and gradually recovered to a calm level in August,we select the rate overlimit anomaly of Shandan resistivity before moderate strong seismic activity in the Qilian mountain seismic zone and its vicinity from 2014 to 2022 to summarize the seismic response index.We predict the seismic risk of the gradually quiet Qilian mountain seismic belt by using the rate overlimit anomaly of the Shandan resistivity from August to December,and determine whether the seismic activity level near the Shandan observation station is really reduced.The results show that the rate overlimit anomaly still exists in the Shandan resistivity,which indicates that the seismic risk still exists in the Qilian mountain seismic zone and the seismic activity level has not weakened.