基于小波变换的2018年永清M_(S) 4.3地震前易县地震台形变观测数据分析

Analysis of deformation observation data at Yixian Seismic Station before the Yongqing M_(S) 4.3 earthquake in 2018 based on wavelet transform

2018年2月12日河北省廊坊市永清县发生M_(S) 4.3地震,易县地震台形变观测数据出现异常变化。选取2017年6月—2018年2月易县地震台DSQ型水管仪和VP型宽频带垂直摆EW向数据记录,采用db4小波变换方法进行分析,结果发现:水管仪EW向小波分解的第6和第7阶细节存在周期为64—256 h的信号,垂直摆EW向小波分解的第5、6、7阶细节中存在周期为32—256 h的信号,均偏离正常动态背景,不属于自然环境干扰,应为河西务断裂正断性质的破裂所致。

On February 12,2018,the M_(S) 4.3 earthquake occurred in Yongqing County,Langfang City,Hebei Province,and the deformation observation data of Yixian Seismic Station showed anomalous changes.The EW component data of DSQ water pipe tiltmeter andVP broadband vertical pendulum at Yixian Seismic Stationfrom June 2017 to February 2018 are selected and analyzed by using the db4 wavelet transform method.It is foundthat there are signals with a period of 64-256 hours in the 6th and 7th order details of wavelet decomposition of the water pipe tiltmeter EW component and signals with a period of 32-256 hours in the 5th,6th,and 7th order details of wavelet decomposition of the vertical pendulum EW component,all of which deviate from the normal dynamics and do not belong to natural environmental interference and should be caused by the normal rupture of the Hexiwu fault.