f Using the pseudospectral method on curved grids for 2D elastic forward modelling

The Fourier pseudospectral method is well-known for its accuracy and efficiency. Its main advantage is the low number of grid points per minimum wavelength implying a considerable reduction in computer memory and CPU-tune. However, using the pseudospectral method on a warse Cartesian grid, which has a sufficient size to propagate an impulse, leads to spurious diffractions from the "stair-case" representation of the curved interfaces. To deal with this problem, when using Cartesian approximations, a much finer grid is needed and thus the spectral efficiency is destroyed.