Elastic Wave Modeling Using the Cell-based Finite Differences in Anisotropic Media

Since seismic anisotropic features are often found in geological structures, we need to describe anisotropic features in seismic modeling and inversion. Although a number of modeling algorithms were developed to address seismic anisotropy, we still need to develop a simple but accurate modeling algorithm to simulate geological-scale models. For such a modeling algorithm for anisotropic media, we extend a time-domain finite-difference method based on the cell-based grid set to anisotropic media. Considering that the cell-based finite-difference method only employs displacements and its accuracy is verified for isotropic Lamb's problem, we can expect that our anisotropic modeling algorithm can also achieve computational efficiency as well as accuracy. Since any interpolations are not needed in our algorithm, we can also simulate a model whose material properties abruptly change. In order to reduce artificial reflections originating from the outer boundaries of a model, we slightly modify Higdon's absorbing boundary conditions. Numerical examples show that our modeling algorithm can properly address anisotropic features. To qualitatively analyze the accuracy of our algorithm, we need to compare numerical solutions with analytic solutions and also apply it to complicated models.