川滇强震震前短期阶段地震活动空间异常特征  

Spatial Characteristics of Seismicity Anomaly in a Short Term before the Strong Earthquakes in Sichuan and Yunnan

作　　者：刘翔[1] 苏有锦[2] 和宏伟[2] 李宗兴[3] 

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026 [2]云南省地震局,昆明650224 [3]保山市地震局,保山678000

出　　处：《地震研究》2005年第4期313-319,共7页Journal of Seismological Research

基　　金：云南省地震局"十五"重点项目"云南西部地震监测防御中心建设"资助(YN150105T037-045)

摘　　要：对1973年以来川滇地区21次6级以上强震的震前地震活动进行了全时空扫描, 发现大多数强震在孕育中期至短期阶段,震源附近会出现两条或两条以上3级或4级中小地震条带.与强震孕育中期阶段相比,在强震孕育的短期阶段中小地震条带方向出现明显偏转,偏转角度为15°～150°.中小地震活动在空间上的这种动态异常,可作为强震孕育、发展至短期阶段的一项标志.There have been 21 M≥6 earthquakes occurred in Sichuan and Yunnan since 1973. We do a complete timespace scan of the seismicity before these strong earthquakes. The results show that in the process that most strong earthquakes developed from medium term to short term, 2 or above 2 M = 3 or M = 4 earthquake stripes would appear in the area near the epicenters. Compared with the earthquake stripe in the seismogenic medium term, the direction of the stripe in seismogenic short term had an obvious deflection of 15°- 150°. This spatial anomaly of moderate and small earthquake activity can be taken as an index that a strong earthquake develops to short-term stage.

关 键 词：地震条带 空间异常 动态变化 短期 川滇地区 

分 类 号：P315.5[天文地球—地震学]