Elastic Wave Finite-Difference Simulation Using Discontinuous Curvilinear Grid with Non-Uniform Time Step: Two-Dimensional Case

drs.amin widjaya tunggal;

A discontinuous grid finite-difference (FD) method with non-uniform time step Runge–Kutta scheme on curvilinear collocated-grid is developed for seismic wave simulation.We introduce two transition zones: a spatial transition zone and a temporal transition zone, to exchange wavefield across the spatial and temporal discontinuous interfaces. A Gaussian filter is applied to suppress artificial numerical noise caused by down-sampling the wavefield from the finer grid
to the coarser grid.We adapt the non-uniformtime stepRunge–Kutta scheme to a discontinuous grid FD method for further increasing the computational efficiency without losing the accuracy of time marching through the whole simulation region. When the topography is included in the modelling, we carry out the discontinuous grid method on a curvilinear collocated-grid to obtain a sufficiently accurate free-surface boundary condition implementation. Numerical
tests show that the proposed method can sufficiently accurately simulate the seismic wave propagation on such grids and significantly reduce the computational resources consumption with respect to regular grids.