2.5D Elastic Finite-Difference Modeling

Finite difference modeling of elastic wavefields in 2.5D is described in the velocity-stress formulation for anisotropic media. The 2.5D modeling computes the 3D elastic wavefield in a medium which is translation invariant in one coordinate direction. The approach is appealing due reduced storage and computing time when compared to full 3D finite difference elastic modeling. The scheme handles inhomogeneities in mass density and elastic moduli, includes free-surface and perfect matched layers as absorbing boundaries. High order finite difference operator allows the use of a coarse mesh, reducing the storage even more without producing numerical dispersion and numerical anisotropy. Numerical experiments show the accuracy of the scheme, its computational efficiency and the importance of 2.5D modeling in complex elastic media.