摘要
使用波形特征分析和时频分析等方法,对2021年8月11日山西云冈M_(L) 3.0地震事件进行分析研究。结果表明:本次地震事件波形既具有天然地震波形特征,又与非天然地震波形特征相似。具体表现在以下3方面:(1)垂直向P波初动方向上、下均有,呈象限分布,S波段振幅大于P波段,波形衰减缓慢;(2) 3个近台记录到明显的短周期面波信号;(3)地震高频成分丰富,频带范围较宽,S波后面的面波频率低、周期大,能量优势频段集中在1 Hz左右。对比塌陷、爆破等非天然地震事件的典型特征,结合区域地震发震背景,判定本次地震是发生在大同矿区内的一次天然地震,因本次地震同时诱发了浅层煤矿开采区内矿井顶部高应力岩体发生陷落,故本次地震波形表现为天然地震波形信号叠加塌陷波形信号的特征。
Based on the waveform characteristics and time-frequency analysis method,this paper analyzes and studies the Yungang ML 3.0 earthquake in Shanxi Province on August 11,2021.The results indicate that the waveform of this earthquake exhibits both natural seismic waveform characteristics and similarities to non-natural seismic waveforms.Specifically,it is observed in three aspects:①The first-motion direction of vertical P-wave is both upward and downward,with a quadrant distribution,and the amplitude of the S-wave is greater than that of the P-wave,with a slow waveform decay.②Three nearby stations recorded distinct short-period surface wave signals.③The earthquake exhibits rich high-frequency components,with a wide frequency band range.The frequency of the surface wave following the S-wave is low and the period is long,and the dominant frequency band of energy is concentrated around 1 Hz.By comparing the typical characteristics of non-natural seismic events such as collapse and blasting,and considering the regional seismic background,it is determined that this earthquake is a natural earthquake that occurred in the Datong mining area.Due to the collapse of the top high-stress rock mass in the shallow coal mining areainduced by the earthquake,the waveform of this earthquake is characterized by the superposition of natural seismic waveform signals and collapse waveform signals.
作者
张玲
李丽
ZHANG Ling;LI Li(Shanxi Earthquake Agency,Taiyuan 030021,China;National Continental Rift Valley Dynamics Observatory of Taiyuan,Shanxi Province 030025,China)
出处
《地震地磁观测与研究》
2023年第3期27-33,共7页
Seismological and Geomagnetic Observation and Research
基金
地震科技星火计划(项目编号:XH210402Y)
山西省地震局科研重点项目(项目编号:SBK-2323)
山西省应用基础研究计划青年基金面上项目(项目编号:201901D211549)。
