2008年新疆于田M_S7.3地震前区域地震活动和应力状态特征初步研究  

Preliminary research on the characteristics of regional seismic activity and stress state before the 2008 M_S7.3 earthquake in Yutian,Xinjiang of China

作　　者：王琼[1] 聂晓红[1] 温和平[1] 

机构地区：[1]新疆维吾尔自治区地震局,中国乌鲁木齐830011

出　　处：《地震学报》2009年第3期235-244,共10页Acta Seismologica Sinica

基　　金：国家科技支撑计划项目(2006BAC01B03-04-02)资助

摘　　要：从区域地震活动和中等地震震源机制特征的角度,初步研究了2008年新疆于田7.3级地震前区域地震活动和应力场的应力状态特征.结果表明,于田7.3级地震前区域地震活动存在中短期异常特征.一方面,该地震前1年其震区500km范围内中强震以及西昆仑地震带和阿尔金地震带3.5级以上地震出现了增强活动;另一方面,该地震前出现了4级地震孕震空区和近乎共扼分布的3.5级地震密集条带异常图象.于田7.3级地震前新疆区域应力场和震源区及其附近局部应力场的应力状态发生了一定程度的改变,拉张作用力相对挤压作用力有所加强.这可能是于田7.3级地震前新疆和于田震区及其附近具有正断层性质的中等地震增多的原因.By analyzing regional seismic activity and focal mechanism solutions of medium earthquakes, we did a preliminarily research on the characteristics of regional seismicity and stress state before the 2008 Yutian Ms7.3 earthquake. It is noticed that the regional seismicity showed middle-short term abnormal before the Ms7.3 earthquake, i. e. , mid-strong earthquakes within 500 km from the source and Ms ≥3. 5 earthquakes in the western Kunlun and Aerehin seismic belt increased one year before the Ms7.3 earthquake. There appeared abnormal pattern of seismic gap of Ms≥4.0 earthquakes and nearly conjugate dense belt of Ms≥3.5 earthquakes before the Ms7.3 earthquake. Both Xinjiang regional stress field and local stress field around the source region were changed to some extent before the Yutian MsT. 3 earthquake, with tensional action being strengthened in comparison with the compressional one. This may explain why medium earthquakes of normal-faulting type in Xinjiang and around the Yutian source region increased before the MsT. 3 earthquake.

关 键 词：2008年新疆于田地震 区域地震活动 应力状态 

分 类 号：P315.5[天文地球—地震学]