Seismic wave modelling using the boundary element method
type: CreativeWork
description: The main objective of this thesis is to use the boundary element method as an efficient and advantageous numerical approach to model the seismic signals received at selected receiver points due to a source located within a geophysical structure. These signals may travel through different geophysical structures. This work determines whether rock interfaces can be identified from the signals received at selected points. The method proves to be most satisfactory and more easily applicable for unbounded media than for bounded media. Each layer in the media of interest is assumed to be linearly elastic, homogeneous and isotropic. This assumption is used for both two- and three-dimensional geometries. Throughout this research linear and constant time approximations are used to represent the displacements and tractions, respectively. With the use of these temporal variations all time integrations are evaluated analytically. The two-dimensional boundary kernels and internal flux kernels have been derived. New kernels for boundary and internal points have also been obtained for three-dimensional scalar waves. In addition, the three­ dimensional elastodynamic boundary kernels have been evolved. Constant elements are normally employed to discretize the boundary. To determine the dynamical response constant elements are seen to be well suited for the geometries used here. The improper integrals are evaluated analytically in two dimensions. In three dimensions two different techniques are used to cope with the singularities. Some available computer codes for the boundary nodes are extended to determine material behaviour at internal points. For three-dimensional cases some programs are developed with the help of the two-dimensional programs. For layered materials these codes are expanded for each layer as subprogram. In spite of the fact that the existence of the interfaces makes the solution of the problem tend to instability, this analysis shows that the BEM is capable of trea…
abstract: The main objective of this thesis is to use the boundary element method as an efficient and advantageous numerical approach to model the seismic signals received at selected receiver points due to a source located within a geophysical structure. These signals may travel through different geophysical structures. This work determines whether rock interfaces can be identified from the signals received at selected points. The method proves to be most satisfactory and more easily applicable for unbounded media than for bounded media. Each layer in the media of interest is assumed to be linearly elastic, homogeneous and isotropic. This assumption is used for both two- and three-dimensional geometries. Throughout this research linear and constant time approximations are used to represent the displacements and tractions, respectively. With the use of these temporal variations all time integrations are evaluated analytically. The two-dimensional boundary kernels and internal flux kernels have been derived. New kernels for boundary and internal points have also been obtained for three-dimensional scalar waves. In addition, the three­ dimensional elastodynamic boundary kernels have been evolved. Constant elements are normally employed to discretize the boundary. To determine the dynamical response constant elements are seen to be well suited for the geometries used here. The improper integrals are evaluated analytically in two dimensions. In three dimensions two different techniques are used to cope with the singularities. Some available computer codes for the boundary nodes are extended to determine material behaviour at internal points. For three-dimensional cases some programs are developed with the help of the two-dimensional programs. For layered materials these codes are expanded for each layer as subprogram. In spite of the fact that the existence of the interfaces makes the solution of the problem tend to instability, this analysis shows that the BEM is capable of trea…
author: Sari, Murat
language: eng
date published: 2000
date modified: 2026-07-24T04:39:25Z
provider: University of South Wales
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of South Wales