山西地区6次M_(S)≥4.5地震前地震活动异常总结

Summary of seismometric anomalies of the 6 earthquakes M_(S)≥4.5 in Shanxi region

系统梳理了2000年以来山西地区6次M_(S)≥4.5地震前地震活动异常,结果表明,地震空区/平静、地震条带、显著地震/震群、大同地震窗“开窗”活动等异常在地震发生前具有一定普遍性,且异常基本围绕在震中及附近地区分布,特别是在地震平静/空区、地震条带等异常发展后期出现的显著地震/震群活动,对未来地震发生的地点和时间具有较好的预测意义。异常持续时间与发震间隔统计表明:异常多出现在主震发生前6个月以内,显著地震/震群、大同地震窗“开窗”对未来主震的发生具有短临预测意义。此外,随着区域应力水平的不断增强,在特定敏感地区会发生成组极微震密集活动,监视跟踪这些有别于正常活动背景的极微震活动,对地震短临预测具有一定意义。

This paper systematically analyzed the seismometric anomalies before 6 M_(S)≥4.5 earthquakes in Shanxi region since 2000.The results show that the anomalies including seismic gap or quiescence,seismic belt,significant earthquake or earthquake swarm and the opening of Datong seismic window are commonplaces before the earthquakes.The anomalies are basically distributed around the epicenter and surrounding areas,especially some significant earthquakes or earthquake swarms appear in the later period of the evolution of the anomalies such as seismic gap or quiescence,seismic belt,etc.,which provide a better predictive significance for the location and time of future earthquakes.Statistics on the duration of anomalies and the recurrence interval of earthquakes show that the anomalies mainly occur within 6 months before the main shocks.Significant earthquakes or earthquake swarms and the opening of Datong seismic window have short-term and impending predictive significance for the occurrence of the future main shocks.In addition,with the increasing of regional stress level,a group of intensive ultra-microearthquakes will occur in the specific sensitive areas.Therefore,monitoring and tracking the seismicity of these ultra-microearthquakes that are different from the normal seismicity background has a certain indication for short-term and impending earthquake prediction.