Development of New Computational Method for Crustal Deformation with Boundary Elements and Application to Tsunami Simulation

Abstract

We developed a new method to calculate displacement of elastic half-space due to slip of the source fault using Boundary Element Method (BEM). The fault having irregular shape or irregular slip distribution can be modeled continuously to make use of triangular liner element which is usually applied by BEM. However, BEM has a disadvantage that the displacement is usually calculated unstable at an observation point that is near an element due to singularity of Green's function. On the other hand, the displacement is obtained exactly by the developed method to exclude the singularity using PART method by Hayami and Brebbia (1988). For the greatest earthquake that is expected in the future to break out in the Sagami Trough, we calculate the displacement of the seabed by the developed method and by Okada's solution (1985) at first. Next, we perform tsunami simulation using these displacements that are regarded as the initial water levels. Since the displacement calculated by the developed method does not contain the effect of modeling the fault discontinuously which appears in Okada's solution, the tsunami simulation can be executed stably.