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Development of Softwares for Analysis of Elastic Waves

弹性波分析软件的开发

基本信息

批准号：
62850115
负责人：
SASSA Koichi
金额：
$ 4.03万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62850115/
关键词：
Simulation of Elastic Waves Reflection Seismic Exploration Method Evaluation of Rock Mass Ray Tracing Thin Layer 有限差分法

项目摘要

1. Elastic Waves in horizontally layered structure are numerically simulated by a Days-2 code. As the result, the solution of numerical simulation is identical with the theoretical solution in terms of p waves, S waves, Rayleigh waves and reflected waves.2. After modifivation of a Days-2 code to use displacement as a initial input, elastic waves caused by several s wave sources are simulated, and thier characteristics are investigated.3. The possibility in resolution of thin layers by using amplitude of reflected waves is investigated. As the result, the horizontal changes of the thickness of thin layers are estimable by using amplitude of reflected wave.4. The effects of low velocity zone consisting of multiple thin layers on a P wave are investigated. As the results of experiments and numerical calculation, it is clarified that both reflected wave and transmitted wave are formed by the superposition of multiple reflected waves in thin layers.5. The effects of the cavity in rock mass on elastic waves are numerically simulated by a Days-2 code. As the result, due to the existence of the cavity, generation of s wave and the changes of maximum amplitude and period of transmitted P wave are confirmed.6. An effective ray tracing method based on the Huygens' principle is developed in order to use it in the seismic tomography. It is confirmed that thes ray tracing method is suitable for the seismic tomography because of its good accuracy and short calculation time.

1.用DAYS-2程序对水平层状结构中的弹性波进行了数值模拟。结果表明，在纵波、S波、瑞利波和反射波方面，数值模拟的解与理论解一致。将DAYS-2程序修改为以位移作为初始输入，模拟了几种S波源产生的弹性波，并对其特性进行了研究。研究了利用反射波幅分辨薄层的可能性。结果表明，利用反射波幅可以估计薄层厚度的横向变化。研究了由多个薄层组成的低速区对纵波的影响。实验和数值计算的结果表明，反射波和透射波都是由多个反射波在薄层中叠加而成。用DAYS-2程序数值模拟了岩体中空洞对弹性波的影响。结果表明，由于腔体的存在，证实了S波的产生以及传播的P波的最大幅度和周期的变化。为了将惠更斯原理应用于地震层析成像，提出了一种有效的射线追踪方法。结果表明，射线跟踪法精度高，计算时间短，适用于地震层析成像。