2020年于田MS6.4地震与2008年于田MS7.3地震震前次声波特征对比分析

STUDY OF PRECURSOR INFRASOUND WAVES EMITTED BEFORE YUTIAN MS6.4 EARTHQUAKE in 2020 AND YUTIAN MS7.3 EARTHQUAKE in 2008

基于新疆天山次声观测网观测数据研究强震前出现的异常次声波,揭示其信号特征以及与地震发生的时空和强度关系。2020年6月26日于田MS6.4地震发生前6天(6月20日)次声观测网多个测点都同步观测到较强幅度的低频次声波动,次声短时能量分析显示,多个站点在6月20日前后都同步出现频段0.001~0.01 Hz的较强低频次声能量;与2008年3月21日于田M S7.3地震前10天观测的异常信号比较,在波形形态、持续时间、频域能量分布及时频特征方面具有较强相似性;使用区域信号最小方差法估计和田、且末及新源3个测点观测到典型信号源位置,显示震前异常信号来源于后续地震震中附近区域,说明该信号与于田MS6.4地震具有较强的关联性。

We study the precursor and anomalous infrasound waves emitted before strong earthquakes to reveal its signal feature and relationship associated with occurrence of ensuing large earthquakes.Six days before the Yutian MS6.4 earthquake on June 26th,2020,strong low-frequency infrasound waves were observed at several observation points of the infrasound observation network.The short-term infrasound energy analysis shows that the frequency band of 0.001~0.01 appears in many stations before and after June 20th.Compared with the abnormal signals observed 10 days before Yutian M S7.3 earthquake on March 21st,2008,there was a strong similarity in waveform shape,duration,energy distribution in frequency domain and time-frequency characteristics.The typical signal source positions of Hotan,Jimo and Xinyuan are estimated by using the method of minimum variance of regional signals,which shows that the abnormal signals before the earthquake come from the area near the epicenter of the subsequent earthquakes,which indicates the signal has strong correlation with Yutian MS6.4 earthquake.