其他摘要：The numerical solution of the scalar wave equation, arising, for instance, in geophysics and seismic engineering, by means of the spectral finite element method (SFEM) based on the Gauss-Lobatto-Legendre quadrature has been receiving great popularity. The SFEM can be viewed as a higherorder finite element method (FEM) with some advantages such as mass-lumping and less dispersion errors. However, when common explicit time-stepping schemes are employed, the critical time step becomes too restrictive as the polynomial degree increases. In this context, an explicit time-stepping scheme based on numerical Green’s functions is presented to circumvent this drawback. The Green’s functions are explicitly computed taking into account the Runge-Kutta (RK) scheme and a time substep procedure. Unlike the standard Runge-Kutta scheme, the present methodology allows the use of large time steps without loss of accuracy. Numerical simulations of a heterogeneous seismic model in an unbounded medium are presented and analyzed in order to illustrate the effectiveness of the proposed formulation.
