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根据前人研究所得1976年四川省松潘地震序列的震源参数,构造了主要地震事件的断层模型,并计算了该序列中主要地震引起的邻近区域内静弹性库仑应力变化.计算结果显示,松潘地震序列的余震主要集中分布在库仑应力增加的区域,说明大地震较好地触发了余震.计算结果还显示,左旋走滑机制的1号地震(MS=7.2)引起逆断层性质的2号地震(MS=6.7)震源处库仑应力增加了约5bar,说明1号地震对2号地震有明显的触发作用.3号地震也是左旋走滑型事件,计算显示3号震源受到1号和2号地震的共同触发不太明显.通过对右旋走滑断层和正断层理论模型的计算,显示出相邻的右旋走滑断层与逆断层间存在较好的触发关系,而平行走滑断层间的触发关系相对较弱.对比松潘地震序列中3个大震的断层组合关系,研究认为3号地震存在被触发的可能.
According to the source parameters of the Songpan earthquake sequence in 1976 in Sichuan Province, the fault model of the major earthquake events is constructed and the variations of the elastic Coulomb stress in the adjacent regions caused by the major earthquakes in this series are calculated. The calculation results show that the Songpan earthquake The aftershocks of the series are mainly distributed in areas with increased Coulomb stress, indicating that the large earthquakes triggered the aftershocks well.The calculated results also show that the Earthquakes 1 (MS = 7.2) MS = 6.7). The Coulomb stress at source increases about 5 bar, indicating that Earthquake No. 1 has obvious triggering on Earthquake No. 2. The Earthquake No. 3 is also a event of left-lateral strike-slip. Calculations show that Earthquake No. 3 is affected by Earthquakes Nos. 1 and 2 The common triggering is not obvious.The calculation of the right-lateral strike-slip fault and the normal fault model shows that there is a good triggering relationship between the adjacent right-lateral strike-slip fault and the reverse fault, and the triggering relationship between the parallel strike-slip faults Relatively weak.Comparing the fault assemblage relationship of three major earthquakes in the Songpan earthquake sequence, it is considered that the earthquake of No. 3 is likely to be triggered.