Dispersion of Scholte wave under horizontally layered viscoelastic seabed

Abstract

SUMMARY Dispersion inversion of Scholte wave is an effective method for constructing the shear wave velocity models of seabed sediments, but it is usually conducted based on the elastic layered medium theory, which ignores the viscoelasticity of sediments. In this work, we use the transitive matrix method to establish the dispersion equation for Scholte wave under horizontally layered viscoelastic seabed. This equation integrates the kinematic property of seismic wave in a viscoelastic media and the fluid–solid coupling mechanism. The phase velocity and attenuation coefficient dispersion curves of Scholte wave are presented by the real and imaginary parts of the complex-valued roots of the dispersion equation at different frequencies solved by Muller iteration algorithm, respectively. We perform numerical comparisons and analyses on the dispersion curves of Scholte waves for three typical seabed models under both elastic and viscoelastic conditions. Results demonstrate that the seabed viscoelasticity could greatly affect the propagation and dispersion characteristics of Scholte wave. Moreover, the dispersion curves of Scholte wave are sensitive to the variations in S-wave velocity and quality factor of seabed sediments.