We present and analyse a Symmetric Interior Penalty Discontinuous Galerkin (SIPDG) method combined with an explicit hybrid Local Time Stepping (LTS) scheme for solving seismic wave problems in heterogeneous anisotropic elastic media. The discontinuous Galerkin method allows for local adjustment of the mesh size and approximation order, and can deal with unstructured non-conforming meshes of mixed types. Furthermore, when using orthogonal basis functions and an explicit time integration scheme, the method becomes fully explicit and inherently parallel, making it an attractive method for seismic applications involving large three-dimensional domains, sharp material contrasts, and detailed internal structures.@en

Mass-lumped finite elements on tetrahedra offer more flexibility than their counterpart on hexahedra for the simulation of seismic wave propagation, but there is no general recipe for their construction, unlike as with hexahedra. Earlier, we found new elements up to degree 4 that have significantly less nodes than previously known elements by sharpening the accuracy criterion. A similar approach applied to numerical quadrature of the stiffness matrix provides a speed improvement in the acoustic case and an additional factor 1.5 in the isotropic elastic case. We present numerical results for a homogeneous and heterogeneous isotropic elastic test problem on a sequence of successively finer meshes and for elements of degrees 1 to 4. A comparison of their accuracy and computational efficiency shows that a scheme of degree 4 has the best performance when high accuracy is desired, but the one of degree 3 is more efficient at intermediate accuracy. @en