【摘要】 自1997-1998年新疆伽师强震群后,伽师震区余震活动渐趋平静。2003年1月4日伽师发生了5.4级地震,其后50天在距其20km左右在巴楚-伽师地区发生了MS6.8地震,其后发生了7次MS5.0以上强余震,序列的余震丰富、强度大。通过计算几次强余震破裂面上产生的静态库仑破裂应力变化,结合余震活动的时空演化特征定量探讨了强余震活动的可能机理。结果表明,巴楚-伽师MS6.8地震不仅有利于分布与主破裂面方向较一致的余震发生,而且触发了与其共轭方向的地震活动。更多还原

【Abstract】 Since the last M_S6 earthquake event in 1997 to 1998 Jiashi strong earthquake swarm,the seismicity in this region tended to quiet.Then occurred Jiashi M_S5.4 earthquake on Jan.4,2003, and Bachu-Jiashi M_S6.8 earthquake about 20 km far from the M_S5.4 earthquake 50 days later.After that 7 strong aftershocks(M_S≥5.0) followed it,and the aftershocks of the sequence are richer and strong.By calculating static Coulomb rupture stress changes of the mainshock acting on the rupture surfaces of strong aftershocks,combining spatial and temporal characters of aftershock evolution,the quantitatively possible mechanism of the strong aftershock activity is discussed.The result shows that Bachu-Jiash M_S6.8 earthquake not only encouraged saftershock occurring,whose direction of epicenter distribution is consistent with main rupture surface,but also triggered seismicity in the conjugated direction of the main rupture surface.更多还原