The Dispersion Curves of Love Waves in Kelvin-Voigt Viscoelastic Media

The approaches of S-wave velocity and quality factor (Q) inversion of near-surface using surface waves has been developed in the past two decades, but most of them assume the media are of weak attenuation and their Q values are not frequency dependent. In fact, it has been shown that when the near surface media are water saturated with high permeability, it is more reasonable to apply Kelvin-Voigt viscoelastic model. In this paper, a recursive algorithm with analytical derivative of surface wave dispersion eigenfunction is presented, and a fast and stable numerical computation method of phase velocity and attenuation coefficient of Love waves in viscoelastic medium is also given based on Argument Theorem. Then the differences between multi-mode phase velocity dispersion curve of Love waves in elastic medium and that in viscoelastic medium are compared. Results show that all Love wave modes can be divided into two groups according to the phase velocity, and the attenuation of low velocity group is significantly greater than that of high velocity group