山西断陷带地震矩释放现象特征研究

Study on seismic moment release in Shanxi depression zone

对山西及邻区22次M_(L)≥5.0地震前不同时间尺度的累积benioff应变释放特征进行分析,认为约55%的地震震前存在地震矩加速释放现象;同时对地震矩释放异常空间区与主震间的关系进行分析,结果表明,在震前1年内大部分地震震中附近出现大范围椭圆形的地震矩低值区域,且主震震中位于异常区内部或边缘。由此认为,地震矩加速释放现象在山西及邻区具有一定的普遍性,且为中期地震前兆异常。

The characteristics of the Benioff strain release curve in different time scales before 22 M_(L)≥5.0 earthquakes in Shanxi and adjacent areas are analyzed.It is concluded that accelerating moment release exists before half of M_(L)≥5.0 earthquakes.At the same time,this paper analyzed the relationship between the moment release anomaly space and earthquakes and concluded that there is a wide range of low m-value area near the epicenter of the mainshock one year before the earthquake,and the mainshocks are located in or near the anomalous areas.Therefore,we consider that accelerating moment release has a certain generality before ML≥5.0 earthquakes in Shanxi and adjacent areas,and it is the medium earthquake precursor.