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自1997年1月21日开始,在将近4个月的时间内,位于塔里木盆地西北边缘的新疆伽师地区发生了7次Ms≥6.0的大地震.前人地震精定位结果显示这些地震发生在两条相邻的破裂带上.根据前人震源机制解和精定位结果,计算了这7个大地震间库仑应力作用,还分析了伽师震群附近的1996年阿图什地震对伽师地震群的影响.计算结果显示第4个地震震源附近的库仑应力受之前地震影响增加了0.5bar左右,而在第2,3,5和6个地震震源附近的库仑应力均增加了约0.8bar.研究表明通过改变邻区断层上库仑破裂应力状态,1997伽师震群中各地震之间存在明显的应力触发作用.而更重要的是伽师地区的正断层活动促进了雁形走滑断层间发生地震的循环触发.
Since January 21, 1997, nearly 4 months have occurred in the Jiashi area, Xinjiang, on the northwestern margin of the Tarim Basin, seven large earthquakes of Ms≥6.0. The results of the previous seismograms show that these earthquakes occurred at Two adjacent rupture zones.According to the results of focal mechanism solution and precise positioning of predecessors, the Coulomb stress between these seven large earthquakes was calculated and the influence of 1996 Atushi earthquake on Jiashi The results show that the Coulomb stress near the source of the fourth earthquake is increased by about 0.5 bar due to the previous earthquakes while the Coulomb stress near the second, third, fifth and sixth earthquakes is increased by about 0.8 bar The research shows that by changing the Coulomb failure stress state in the adjacent fault, there is a clear stress triggering between the earthquakes in the Jiashi earthquake swarm in 1997. More importantly, the normal fault activity in the Jiashi region promotes the goose-shaped strike-slip fault Earthquake cycle between the trigger.