芦山地震前后龙门山断裂带南段视应力研究  

Study of Apparent Stress on the Southern Segment of Longmenshan Fault Zone around the Lushan Earthquake

作　　者：宫悦[1] 龙锋[1] 易桂喜[1] 赵敏[1] 乔慧珍[1] 王宇玺[1] 

机构地区：[1]四川省地震局,成都610041

出　　处：《震灾防御技术》2013年第4期389-396,共8页Technology for Earthquake Disaster Prevention

基　　金："十二五"国家科技支撑计划项目(2012BAK19B01-01);地震科技专项项目

摘　　要：利用四川台网数字地震记录资料,计算了2008年汶川地震之后、2013年芦山地震之前5年内,龙门山断裂带南段ML3.0级以上地震视应力随时间的变化,以及芦山M7.0级地震序列的视应力值及其时空分布特征。结果表明:①从芦山地震之前1年的时间开始,龙门山断裂带南段有视应力的上升过程;②芦山地震余震序列视应力存在几次比较突出的视应力与震级相关性的被打破以及视应力的突降异常,且在震后3个小时之后,视应力即有明显下降的过程;③从归准化的芦山地震序列视应力σapp的空间分布来看,视应力高值区域分布在主震的西南方向和整个余震区东南边缘,并且这两个高视应力区正好分布在该断层面与华南地块紧密接触的边缘;④主震西侧有一片视应力相对较高的区域;⑤主震以北区域的视应力则相对较低。The change of the apparent stress with time in the southern segment of Longmen Shan fault zone from 2008 Wenchuan earthquake to 2013 Lushan earthquake,as well as the apparent stress values and the space-time distribution of Lushan M7.0 earthquake sequence,is calculated by using the digital seismic data recorded by Sichuan seismic network.The results indicated that：（1） the apparent stress in the southern section of Longmen Shan fault zone has increased in the last year before Lushan earthquake.（2） The apparent stress of the sequence showed sharp decrease,and correlation between apparent stress and earthquake magnitude was obviously broken for several times.The apparent stress decreased significantly three hours later after the earthquake.（3） According to the apparent stress spatial distribution of the normalized Lushan earthquake sequence,two areas with high apparent stress value appeared in the southwest of the main shock and at the southeastern edge of the whole aftershock area,which are at the boundary between the fault plane and the Southern China Block.（4） The apparent stress was relatively high in west of the main shock,whereas is relatively low in the north.

关 键 词：芦山7 0级地震 视应力 龙门山断裂带南段 时空分布 

分 类 号：P315[天文地球—地震学]