A 21-point finite difference scheme for 2D frequency-domain elastic wave modelling

The 21-point finite difference scheme for the frequency-space domain elastic wave forward modelling is designed through optimising the impedance matrix, especially calculating the spatial derivative terms and the mass acceleration terms of the elastic wave displacement equation as accurately as possible. Comparative tests show that the 21-point finite difference scheme is much better in grid dispersion, memory requirement, and computation time than the 9-point scheme and slightly better than the 25-point scheme. The 21-point finite difference scheme is similar to 15% lower in memory consumption and computing time than the 25-point scheme. The numerical examples show that the 21-point finite difference scheme is valid in the sense of the numerical simulation of ideal models.