This article describes a numerical model capable of simulating the fluid-rock processes that appear to preced some earth quakes. More precisely, the two-dimensional finite element-finite difference model can be used for investigating dilatancy and the associated migration of the pore fluids in a water-saturated rock. The numerical model is applied to a tectonically simple region containing a thrust fault. Fault creep is used to produce locl stress concentrations (at fault ends) and dilatancy. Numerical results illustrate the somewhat conflicting requrements on rock permeability in the dilatancy-fluid diffusion model . During the first stage of the process the permeability must be low enough to allow a drop in fluid pressure sufficient to cause vaporization: at a later stage the permeability needs to be large enough to enable the fluid to move suffiicently rapidly into the dilated region. The numerical solution also yields such quantities as surface displacements which can be used for constraining the choice of model parameters for a particular earthquake region.