2020年3月20日蒙古M_(S)5.9地震前地倾斜资料异常特征分析

Analysis on anomaly characteristics of ground tilt data before Mongolia M_(S)5.9 earthquake on march 20,2020

采用形态法和小波分析法,分析2020年3月20日蒙古M_(S)5.9地震震中距400 km范围内巴里坤、富蕴和芨芨台地震台倾斜观测资料的震前异常特征。结果表明:3套资料在震前均具有明显的中短期异常,分别表现为反向趋势变化、破年变形态和倾斜速率减缓的特征;使用db4小波对3套资料进行分析,其6—9阶在震前出现周期为几天至几十天的低频短期异常,同时巴里坤水平摆倾斜仪EW分量8—9阶趋势异常较显著。

In this paper,the methods of morphological and wavelet analysis are used to analyze the anomaly characteristics of tilt data at Barkol,Fuyun and Jijitai stations within 400 km of Mongolia M_(S)5.9 earthquake on March 20,2020.The results show that there are obvious medium-short term anomalies in the three sets of data before the earthquake,which are characterized by inverse trend,abnormal annual variation and slowing down of tilt rate respectively;Using db4 wavelet to analyze the three sets of data,it is found that there are short term low-frequency anomalies of order 6-9 with periods from several days to dozens of days before the earthquake,and the trend anomalies of order 8-9 of EW component of Barkol horizontal pendulum tiltmeter are also significant.