Add to ORKGWe present a finite-volume method for the modeling of wave propagation on irregular triangular grids. This method is based on an integral formulation of the wave equation via Gauss's theorem and on spatial discretization via Delaunay and Dirichlet tessella-tions. We derive the equations for both SH and P-SV wave propagation in 2-D. The method is of second-order acr.uracy in time. For uniform triangular grids it is also second-order accurate in space, while the accuracy is first-order in space for nonuniform grids. This method has an advantage over finite-difference techniques because irregular interfaces in a model can be represented more accurately. Moreover, it may be compu-tationally more efficient for complex models