2003年2月24日新疆巴楚—伽师Ms6.8地震的静态库仑应力触发作用

2003年2月24日新疆巴楚—伽师发生Ms6.8地震，截止到2004年6月30日发生了7次Mw5以上的中强余震，序列的余震丰富、强度大。本文求算了Ms6.8主震及其序列中主震和中强余震共同在后续中强余震（7次Mw5.0以上余震）破裂面上产生的静态库仑破裂应力变化情况。考虑到震中定位的误差，分几种情况分别讨论了此次Ms6.8主震及其中强余震产生的库仑破裂应力变化情况，并定量分析了Ms6.8地震序列静态库仑破裂应力变化与断层类型的关系及其静态应力触发模型作用的延迟时间和空间范围。认为采用哈佛大学矩心矩张量目录的震源机制解、矩心深度和新疆震中定位结果较合理，由此得到的7次中强余震均发生在库仑破裂应力增加的区域。综合分析表明，巴楚—伽师Ms6.8主震对后续中强余震具有一定的触发作用，而中强余震之间的触发作用不显著。但由于目前震源定位精度的限制，不能肯定序列中7次中强余震是完全受Ms6.8主震触发而发生的。

Stress Triggering of Static Coulomb Stress of Xinjiang Bachu-Jiashi Earthquake of Ms 6.8, Feb. 24, 2003

An arthquake of M_S 6.8 occurred in Bachu-Jiashi county,Xinjiang,on Feb.24,2003.There were 7 strong aftershocks greater than M_W 5 till June 30th,2004,and aftershocks of the sequence were richer and stronger.The article calculates the change of static stress of M_S 6.8 mainshock,both mainshocks and aftershocks on the rupture surface of sequent mid-strong aftershocks.Considering epicenter location error,the article discusses the change of static stress of M_S 6.8 mainshock,both mainshock and mid-strong aftershocks in different aspects,and analyses quantitatively the relation between static stress change of M_S 6.8 sequence and fault type,and delay time and spatial range effected by the static triggering model.It is reasonable to employ the focal mechanism solution and depth in Harvard CMT catalogue and Xinjiang results of the location epicenter,and 7 mid-strong aftershocks occured all in the increasing region of coulomb fracture stress,which passes signal test.A general analysis shows that Bachu-Jiashi earthquake of M_S 6.8 triggered sequent mid-strong aftershocks in certain degrees,but triggering between mid-strong aftershocks is not remarkable.With the limitation of present source location precision,we are not sure that 7 events were completely triggered by M_S6.8 mainshock.