华北地区应力状态与地震关系的研究

A STUDY OF THE RELATIONSHIP BETWEEN STRESS STATE AND EARTHQUAKES IN NORTH CHINA AREA

通过对华北地区6个应力台站实测资料的分析处理,并结合近几年华北地区发生的四个5级以上地震,从总体应力场角度对华北地区的相对应力与地震的关系进行了研究讨论。发现华北地区5级以上中强震与各单点应力状态的变化无明显关系,而对于整个区域的平均应力状态的变化却密切相关,这种关系不但表现在水平空间各方向正应力的变化,而且表现为正东西方向和正南北方向的剪切应力变化,二者对华北强震的发生起着主导作用。

Based on the analysis of observed stress data from 6 stations in North China area and by combining 4 earthquakes of M≥5 occurred in North China area in recent years, a study is made for the relationship between relative stress and earthquakes in North China area. It has been found that the moderately strong-earthquakes of M≥5 in North China area have no clear relation with the variation of stress state at each single observational point, but have close relation with the variation of mean stress state of the whole region, such a relation is not only shown in the normal stress variation in different directions in horizontal space, but also shown in the shear stress variation in due eastwest direction and due northsouth direction, the both play a leading role in the occurrence of sstrong earthquakes in North China area.