Cabrillo is a staggered Pseudo-spectral finite difference code for acoustic elastic and poroelastic media. The advantage of a FD approach is that a geometric complicated media can be modeled. Staggered grids are advantageous as it provides more accuracy and can handle larger velocity and density contrasts than using a classic grid. In a Pseudo-spectral method the spatial derivatives are evaluated by a wavenumber multiplication in the wavenumber domain. The advantage of this approach is stability and reduction in memory and the number of computations required to obtain a given accuracy. Usually FD codes cannot handle attenuation. But, using Biot theory it is also possible to incorporate attenuation into the media by increasing the viscosity. Much care has gone into obtaining a fast and reliable code. The kernel of the code is based on a code from University of Dallas. The Temperton Fourier transform is used as the FFT (obtained from the University of Hamburg). This allows the number of grid points to be any combination of prime factors up to 11.
P. Gerstoft, "CABRILLO 1.0: Acoustic, elastic and poroelastic finite difference modelling,"Peter Gerstoft