Study on the generation of earthquake motions considering fault rupture process

在这项研究中，我们使用三维有限元方法对断层破裂机制和断层上和断层附近的强震运动进行了参数分析。首先，我们检查了断层长度对破裂传播过程的影响，断层面上的位错震级，以及产生的地震运动。然后，将三维分析结果与二维分析结果进行了比较。主要研究结果如下：(1)破裂沿初始剪应力方向快速传播，然后破裂锋I以同心圆形状逐渐延伸。(2)断层长度越长，断层位错的平均震级越大，接近二维结果。由三维分析得到的位错与由二维分析得到的位错之间的关系表示为断层长度与宽度之比的函数。(3)在波形对比中，当观测点恰好在断层上时，三维波的振幅和相位与三维波的振幅和相位相符合较好，但距离断层越远，两者的差异越大。其次，利用三维有限元法模拟了2000年10月6日发生的鸟鸟县西武地震的断层破裂过程和加速度记录。我们分析了两种情况，即Case1，断层上的应力降分布是恒定的，Case2，其分布与反演分析得到的分布相似。研究了位错的破裂过程和强度，并将模拟加速度与记录加速度进行了比较。我们发现这种错位是可再现的，但在模拟加速度记录时需要考虑地面条件、风帆的非线性特性等因素。第三，开发了三维仿真的预处理器和后处理器，构建了基于非线性三维有限元法的在线模拟器。利用系统的周转时间来生成数据集进行分析处理，并对得到的数据进行语法化简。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