2.5D modelling of elastic waves in anisotropic media using the spectral-element method ? a preliminary investigation

Abstract

The spectral-element method provides an accurate alternative to the finite element method for modelling elastic waves in anisotropic media. However its high computational overheads make it impractical for inversion. With the aim of reducing the overheads, we have implemented 2.5D spectral-element modelling of elastic waves, initially for vertically transversely isotropic (VTI) media. We have incorporated perfectly matched layers to minimise artificial boundary reflections, using the split gradient operator for the time domain and complex coordinate stretching for the frequency domain. Traditional 2D modelling does not reflect the true coupling between wave modes. Our preliminary results, presented as images of seismic waveforms, illustrate the expected coupling. We also present an intuitive explanation of our unique implementation of the spectral-element method.