大同－阳高两次地震的对比分析

THE COMPARISON AND ANALYSIS OF THE TWO DATONG-YANGGAO EARTHQUAKES

１９８９年１０月，１９９１年３月，在山西北部大同盆地先后发生Ｍｓ６．１、Ｍｓ５．８两次中强地震。对比这两次地震的序列、空间分布及能量释放等存在很大差异。两次地震属同一地震序列，５．８级地震的活动规律具有晚期强余震的特点，是６．１级地震活动的一次大的起伏。进一步分析表明，大同—阳高的两次地震活动，以及在此期间山西地区发生的一系列５级左右地震活动，是华北地区区域应力场增强，较大范围内应力增加和传递的结果。

Two moderately strong shocks with Ms= 6.1 and Ms= 5.8 occurred in the Datong basin North Shanxi province in October, 1989 and March 1991 respectively. there are much differences in sequence, spatial distribution,energy release and so on between the two earthquakes. Of the two earthquakes which belong to identical earthquake sequence, the earthquake with Ms= 5.8 having the characteristic of late strong aftershock is a major undulation of the earthquake with Ms= 6.1. Further analysis shows that the two earthquakes in Datong-Yanggao region and a series of earthquake events within same period of the two shocks in Shanxi area resulted fromstrengthening of the regional stress field in North China and increasing and transmitting of stress in a large area.