Study on the generation of earthquake motions considering fault rupture process

在这项研究中，我们进行了参数分析，以检查断层破裂机制和强震运动的断层上和附近的三维（3D）有限元方法。首先，我们研究了断层长度对破裂传播过程、断层面位错大小和产生的地震运动的影响。并将三维分析结果与二维分析结果进行了比较。主要结果如下：（1）破裂沿初始剪应力方向快速扩展，破裂前缘I逐渐呈同心圆状扩展。(2)断层长度越长，位错的平均大小越大，并接近二维结果。由三维分析得到的位错量与二维分析得到的位错量之间的关系表示为断层长度与宽度之比的函数。(3)在波形的比较中， 关于我们 当观测点位于断层上时，三维地震波的振幅和相位与三维地震波的振幅和相位吻合较好，但当观测点距断层较远时，两者的振幅和相位相差较大。其次，我们用三维有限元法模拟了2000年10月6日鸟取县西武地震的断层破裂过程和加速度记录。我们分析了两个案例，即，断层上的应力降分布为常数，断层上的应力降分布与反演结果相似。破裂过程和位错的大小进行了检查和模拟的加速度与记录进行了比较。我们发现，错位是可再现的，但它是必要的，以考虑地面条件，帆的非线性特性等来模拟加速度记录。第三，我们开发了三维模拟的前处理器和后处理器，并建立了在线模拟器采用非线性三维有限元法。借助系统的周转时间生成数据集进行分析处理和绘图，对得到的数据进行语法精简。少

In this study, we performed parametric analyses to examine fault rupture mechanism and strong earthquake motions on and near a fault by using three dimensional (3D) finite element method. First, we examined the effect of the length of the fault on the rupture propagation process, magnitude of the dislocation on the fault plane, and generated earthquake motions. Then, the comparison between the results from 3D analyses and those from2D analyses was made. The main results were as follows;(1) The rupture propagates in the direction of the initial shear stress at fast, and then the rupture front I gradually extends in the shape of a concentric circle.(2) The average magnitude of dislocation becomes large and approaches to a 2D result as the fault length becomes long. The relationship between the dislocation obtained from the 3D analyses and those from the 2D ones was expressed as a function of the ratio of the length of the fault and the width of it.(3) In the comparison of wave forms, the … More amplitude and the phase of the waves from 3D analyses and from D ones correspond well when the observation point is just on the fault, but the difference between them becomes increases when the distance from the fault becomes large.Next, we simulated the fault rupture process and acceleration records of the 2000 Tottoriken-seibu earthquake which occurred on October 6, 2000 by 3-D FEM. We analyzed two cases, I.e., Case1, the distribution of the stress drop on the fault was constant, Case2, the distribution was similar to that one which was obtained by the inversion analysis. The rupture process and magnitude of the dislocation were examined and simulated accelerations were compared with recorded ones. We found that the dislocation was reproducible but that it was necessary to consider ground condition, nonlinear characteristics of sail, etc. to simulate acceleration records.Third, we developed a preprocessor and a post processor for the 3D simulation and constructed on-line simulator acing nonlinear 3D finite element method. By virtue of the system turn-around time to generate dataset for the analysis and processing and drawing the obtained data was grammatically reduce. Less