UNSTRUCTURED NODAL DISCONTINUOUS GALERKIN SIMULATION OF SEISMC WAVE PROPAGATION IN HETEROGENEOUS SOLID MEDIA

We present a study of elastic wave propagation in heterogeneous media. The Discontinuous Galerkin Method is applied to solve the elastodynamic equations which represent seismic wave propagation. The elastodynamic equations are transformed into a stress-velocity formulation. The Discontinuous Galerkin Method is a finite element that allows a discontinuity of the numerical solution at element interface. Through a proper choice of the flux computation points, the method only requires communication between elements that have common faces. . The domains are discretized into unstructured straight-sided triangles that allow enhanced flexibility when dealing with complex geometries. The stress and velocity fields are expanded into a high-order polynomial spectral approximation over each triangular element. We use perfectly matched layer (PML) as absorbing boundary conditions. The utilization of high-order Jacobi polynomials as basis functions has been shown to be more efficient in reducing the numerical dispersion and numerical dissipation. Temporal discretization utilized explicit low-storage Runge Kutta 4 th order method. We compare the numerical results to the available exact solutions and the comparison shows a good agreemen