中强地震前地震活动的长程关联及预测效果

Long-Range Association of Seismic Activities Prior to Great or Moderate Earthquakes and Their Predicting Effects

将孕震系统看作是一个自组织临界系统,中强地震发生前在一定区域内的地震具有长程关联的特征,可以用地震空间相关长度增长来表示.在2003年10月25日甘肃山丹-民乐6.1级地震前,研究了甘肃及邻区几个区域的空间相关长度增长的现象,得到了3个地震危险区.按照发震危险性的大小它们是:门源地区、天祝-古浪地区和天水地区,山丹-民乐6.1级地震发生在地震危险性最大的地区,即门源地区.表明地震空间相关长度分析对中强地震的发震地点的预测是一种有效的方法.

Earthquake preparation system can be looked upon as a self-organized critical system. The earthquakes in a certain area have a characteristic feature of long-range association before th occurrence of great or moderate earthquake and it can be expressed by using seismic spatially correlated length. Prior to the Shandan-Minle earthquake （M= 6.1） which occurred on Oct. 25, 2003 we analyzed the phenomena of growing seismic spatial correlation in several areas of Gansu and its nearby areas and obtained three seismic risk regions. According to the order of the risky extend they are Menyuan, Tianzhu-Gulang and Tianshui areas. The Shandan-Minle earthquake occurred in the most risky area, i. e, , Menyuan area. It shows that analyzing the seismic spatial correlation is an effective method to predict the occurring place of great or moderate earthquakes.