中文摘要：

利用2003年7月21日、10月16日大姚6．2、6．1级地震余震序列的震源机制解资料，采用滑动方向拟合法反演出大姚两次强震的构造应力，定量给出其构造应力变化量。以反演得到的2003年大姚6．2、6．1级地震构造应力为基础，分别计算两次强震后产生的静态库仑破裂应力变化，研究大姚6．2级地震引起的应力变化是否触发了6．1级地震。结果显示：两次地震发生后震源区构造应力场最大主压应力S，作用由北东向近水平作用为主转为北东东向水平作用，6．2级地震对6．1级地震有明显的触发作用。

英文摘要：

Using the focal mechanism solutions of aftershock sequence of Dayao M6. 2, M6. 1 earthquakes occurred on Jul. 21 and Oct. 16 in 2003, we inversed the tectonic stress of these two strong earthquakes by slips direction fit- ring method and obtained their tectonic stress variation. Basing on the tectonic stress of these two earthquakes, we calculated static coulomb failure stress variation after these two strong earthquakes and studied whether the tectonic stress of Dayao M6. 2 earthquake triggered the Dayao M6. 1 earthquake. The results showed that the maximum principal stress S1 of tectonic stress field which was nearly horizontal action with NE turned to NEE di- rection in the focal zone after two strong earthquakes. The Dayao M6.2 earthquake on Jul. 21 apparently trig- gered the Dayao M6. 1 earthquake on Oct. 16 in 2003.