The higher order Born approximation applied to improve the solution of seismic response of a three-dimensional canyon computed by the Indirect Boundary Method

Abstract

The accuracy of a numerical scheme based on the Boundary Element Method and the higher order Born approximation to solve problems of seismic wave propagation in complex media is analyzed in terms of its CPU time consumption and computer memory requirement. In this scheme, using the conjugate gradient approach, in which, additionally, the coefficient of relatively small values can be eliminated, solves the system of simultaneous linear equations to determine the strength of wave contribution of each element. The higher order Born approximation is used to properly select such coefficients without affecting significantly the accuracy of the overall solution. In this study, we apply this numerical scheme to compute the response of a three-dimensional semi-spherical canyon to an obliquely incident SH wave. It is shown that the third-order Born approximation provides an accurate solution and at the same time reduce drastically the CPU time and memory allocation.