地震场源应变前兆的区别及其三维有限元模拟

以组合模式为基础,用三维有限元方法计算了两个模型,主要研究结论是:①在大地震发生前,调整单元首先破裂,其应变随时间变化曲线呈准"λ"型;②在调整单元破裂后,积累单元破裂,其应变随时间变化曲线呈"λ"型;③在断层垂直方向上应变衰减很快,而沿断层走向方向衰减很慢;④场区各单元的情况很复杂,其应变随时间变化的曲线呈非"λ"型。并用数值分析方法证实了组合模式的正确性,还用结论(1)解释了几种前兆现象。

The Difference between Strain Precursors within Seismic Source and Seismic Field Regions and Three-dimension Finite Element Modeling

In this paper, on the basis of the combination pattern, the authors calculated two models by using the 3-D element method. The major conclusions are:(1)The adjustment element breaks firstly before a strong earthquake takes place, the variation of strain with time is a quasi-lambda curve.(2)The accumulative element breaks after the adjustment element broke, the variation of strain with time is a lambda curve.(3)The strain attenuates quickly along the perpendicular direction of the fault strike, but slowly along the fault strike.(4)The situations of the elements in a seismic field region are very complex, and their strain changing with time are non-lambda curves. The correctness of the combination pattern is confirmed by using mathematic method, and some precursor phenomena are interpreted by using the conclusion(1).