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本文描述了一个解时空反演问题的方法.通过把华北地区看成是由24条主要断裂带组成的地质构造骨架,在15公里深处按照平面应变的理想塑性体处理,用有限单元方法计算了本地区在均匀边界外力作用下发生地震危险的地带.然后用逐次降低断层内摩擦系数的办法,模拟近十二年来历次大地震,计算释放应力后应力场的变化、断层的错动.将计算结果和实测资料进行对比,对各个力学参数和构造骨架进行了多次修改,使它们尽量接近.结果说明本方法能够基本上重复近十二年来的地震迁移规律,并可望对未来的地震危险区提出参考意见.结果还说明地震以后在沿断层错动方向的左前方有一狭窄扇形地带安全度增加,而其余较大地区由于断层处的应力释放使剪破裂的危险度有些增加.
In this paper, we describe a method to solve the problem of space-time inversion by treating North China as a geological framework consisting of 24 major faults along an ideal plastic body at a depth of 15 km and using a finite element method The region where the seismic hazard occurred under the uniform external force is simulated.The successive large earthquakes in the past 12 years are simulated by decreasing the internal friction coefficient of the fault and the change of stress field and the fault of the fault are calculated after releasing the stress The results are compared with the measured data and the mechanical parameters and structural skeleton are modified several times to make them as close as possible.The results show that this method can basically repeat the law of earthquakes in the last 12 years and is expected to predict the future earthquakes The results also show that the safety of a narrow fan-shaped zone increases in the left front of the fault along the fault direction after the earthquake, while in the other large areas, the risk of shear fracture is somewhat increased due to the stress release at the fault.