Modified Generalized R/T Coefficient Method for Surface-Wave Dispersion-Curve Calculation in Elastic and Viscoelastic Media

Abstract

ABSTRACT This article presents an efficient and effective modified generalized reflection and transmission (R/T) (mGRT) coefficient method for dispersion-curve calculation of the Rayleigh and Love waves. We construct a novel dispersion function based on the kernel function for calculating synthetic seismograms in an elastic layered half-space model. It improves the root searching using the monotonicity of the dispersion function in sections between roots. We introduce an auxiliary function to accelerate the root-searching procedure by approximating the number of roots of the dispersion equation. To solve the low-velocity-layer problem for the generalized R/T coefficient method, we turn to the dispersion function of multiple depths. Numerical results indicate that the proposed method is slightly slower than the other most efficient methods including the delta-matrix method and the fast delta-matrix method. Then, we present a technique for the velocity and attenuation dispersion curves in viscoelastic media. The technique is based on jumping features of the dispersion function and converts 2D root-searching problem to 1D minimization problem. The mGRT method is expected to be a useful candidate for calculating dispersion curves in both elastic and viscoelastic media.