1980年以来青海地区震群活动与前震序列特征分析  

Analysis of earthquake group activity and foreshock sequences in the Qinghai region since 1980

作　　者：陈玉华[1] 姚家骏[1] 李戈云 余娜[1] 刘文邦[1] 王培玲[1] 张晓青[1] 

机构地区：[1]青海省地震局,西宁市兴海路1号810001

出　　处：《中国地震》2013年第4期489-500,共12页Earthquake Research in China

基　　金：中国地震局监测预报司2013年度震情跟踪项目"西北地区强震地震活动图像异常总结";青海省地震科学基金项目(2012A05);青海省地震科学基金(2012A04)联合资助

摘　　要：采用青海地震台网资料,系统整理分析了青海地区的震群活动及前震序列,总结了震群活动与中强以上地震的时空关系,检验了前兆震群类型的判断指标。研究认为,青海地区M L≥2震群活动增强对区内6.5级以上地震有一定的中长期时间预测意义,对7级以上地震有一定的时空预测意义。利用MAPSIS软件6项震群参数,以满足4项前兆指标的全组合模式判断前兆震群,对研究区总频次大于40的34个震群进行参数计算,判断出前兆震群24个,占总数的71%。100%前兆震群后发生相应的中强震,部分非前兆震群后也发生相应的中强震;震群对应的中强震80%发生在本地震构造带,对中强震孕育区域有一定的指示意义。青海地区有前震序列的震例较少,仅有的3例,参数计算均不符合前震序列判断指标,对强震无预测意义。Based on the data of Seismic Network of Qinghai Province,the paper analyzes the earthquake group activity and foreshock sequences in the Qinghai region,and with the help of the space-time relationship between the swarm activity and the strong earthquakes,checks the judgement index of the type of the precursory clustering earthquake.The results show that the increasing activity of ML ≥ 2.0 earthquake swarms in the Qinghai region is significant in medium term forecast for Ms ≥ 6.5 earthquakes and in space-time forecast for Ms ≥ 7.0 earthquakes.In order to determine the precursor earthquake swarms,we use any four of all combined modes which meet single index of the precursor earthquake swarms when calculating the 6 parameters of earthquake swarms.By calculating 34 parameters of earthquake swarms which the total frequency is more than 40,we can conclude that there are 24 precursory clustering earthquake which account for 71％ of the total.The corresponding strong earthquakes can happen after the precursory swarms,the same as some non-precursory earthquake swarms.80％ of the strong earthquakes after earthquake swarms are in the present seismotectonic zones.It plays an indicative role for the strong earthquake breeding regions.There were only a few earthquake cases with foreshock sequences in the Qinghai region.The only 3 earthquake cases studied can not make reliable indicators for foreshock sequences and has no significance for strong earthquake forecast.

关 键 词：青海地区 震群活动 前兆震群 前震序列 

分 类 号：P315[天文地球—地震学]