1979年3月2日固镇5.0级地震

本文对1979年3月2日固镇5.0级地震的主震参数、震前的地震活动以及地震序列的特征进行了一些研究。结果表明:震前在震中附近区域存在小震活动的空区。空区形成后,小震的频度、b值、应变释放等参量出现了异常变化。一定区域的波速比在震前也有异常显示。同时,临震前于空区的边缘发生了一组具有某些临震信息的地震。文中也对余震序列的概况作了介绍,指出该序列具有机制稳定、b值较低等与一般余震序列不同的特征。

THE MARCH 2.1979 GUZHEN EARTHQUAKE(Ms=5.0)

In this paper, the main shock parameters of the March 2.1979 Guzhen Earthquake, the seismicity before the main shock and the characteristics of the earthquake sequence are studied. The results show that before the main shock, the seismic gap formed by some small earthquakes exists in a nearby region around the epicenter of the main shock. After the formation of this gap, the frequency of small earthquakes, the value of b, the strain release, etc. show anomalous changes. The velocity ratio in a certain area before the main earthquake shows anomaly too. On Feb. 17.1979, a set of earthquakes with some information about the mainshock occurred on the edge of the gap.The survey of the aftershock sequence is introduced in this paper. And it is pointed out that the sequence is characterized by the stable source mechanism and the lower b value which are different from other general aftershock sequences.