昆仑山口西8.1级地震强余震库仑破裂应力触发研究

LARGE AFTERSHOCKS TRIGGERING BY COULOMB FAILURE STRESS FOLLOWING THE 2001 M_S=8.1 GREAT KUNLUN EARTHQUAKE

20 0 1年 1 1月 1 4日昆仑山口西发生 8.1级地震 ,震后在地震断裂带附近发生了 5次MS>5 .0的强余震 .本文计算了昆仑山口西大地震后 ,主震分别在 5次强余震破裂面上诱发的库仑破裂应力变化 (Δσf) .结果表明 ,其中有 4次强余震发生在库仑破裂应力增加(Δσf>0 )的地区 ,增加的范围为 1 0 -2 ～ 1 0 -1 MPa;有一次强余震发生在库仑破裂应力变化为负的地区 ,Δσf=- 0 .56MPa.本文的结果表明 ,主震位错产生的库仑破裂应力变化是昆仑山口西地震强余震活动的重要原因 。

The great Kunlun, earthquake occurred on Nov.14,2001 in Qinghai Province, China. Five large aftershocks with magnitude larger than 5.0 occurred near the Kunlun fault after main shock. Calculations of the change in Coulomb failure stress rev eal that 4 of 5 large aftershocks occurred in areas with Δσ f>0 (10 -2 ～10 -1 MPa) and one aftershock occurred in an area with Δσ f=-0.5 6 MPa. It is concluded that the permanent fault displacement due to the main shoc k is the main cause of activity of large aftershocks, but not the whole cause.