Efficient numerical surface wave propagation through the optimization of discrete crustal models-a technique based on non-linear dispersion curve matching (DCM)

Abstract

SUMMARY We present a method for reducing the computational costs of numerical surface wave modelling. It is based on the smoothing of thin near-surface layers and discontinuities. Optimal smooth models are found via a constrained non-linear matching of dispersion curves in the period range of interest. The major advantages of our method are that it is independent of the numerical techniques employed and that it does not require modifications of pre-existing codes or meshes. It is, moreover, applicable in cases where the layer thickness is of the order of one wavelength and automatically yields estimates of the appropriateness of the smoothed model. Even though our analysis is based on 1-D media, we demonstrate with a numerical example that the dispersion curve matching can yield satisfactory results when it is applied regionally to laterally heterogeneous models. Also in that case it can lead to considerable reductions of the computational requirements.