Inversion And Dispersion Curve Simulation Of Love Waves In Viscoelastic Media

At present,the geological situation of seismic exploration is becoming more and more complicated.So with the continuous development of seismic exploration,especially for viscoelastic underground media,the technical requirements for surface wave exploration are getting higher and higher.Love wave refers to the horizontal polarization shear wave in the surface layer after repeated reflections at the boundary of the surface layer.Love wave detection is one of the shallow surface detection method.It is very convenient and has high detection precision.Therefore,the study of Love wave has important theoretical and practical significance.Now the study of Love wave has been widely concerned,and has become an important research topic in acoustics and geophysics.Since the Love wave velocity is only related to the shear wave velocity Vs and has kinematics characteristics such as velocity dispersion,this characteristic can reduce the non-exclusive degree of the inversion of the shear wave velocity.In theory,fewer parameters can lead to a more reliable shear wave velocity.Therefore,Love wave is now widely used in a variety of underground survey areas,such as natural earthquake research,engineering geological prospecting.In recent years,with the rapid development of computer technology and the fast upgrade of the equipment in China,Love wave exploration has gradually become a hot topic.First of all,this paper derives the dispersion equation of the Love wave in the layered medium by describing the transverse wave equation and the boundary condition in the medium.Secondly,the numerical program is used to solve the dispersion equation by Matlab,and the Love wave single shot record is simulated by high order finite difference method in the case of horizontal layered complex geological.The comparison of the dispersion curves and the theoretical dispersion curves proves that the method in this paper is correct.The influence of the viscoelastic medium on the Love wave dispersion curve is also discussed.Then,the least squares inversion is used to verify the stability and feasibility of all algorithms and procedures.It is proved that the shear wave velocity obtained by the viscoelasticdispersion curves are more accurate.Finally,we give an example of love wave dispersion curve inversion.This study provides a theoretical basis for the study of the Love wave forward and inversion of layered media.At the same time,it also provides a more complete basic theory for the application of extended Love wave in engineering,and has practical significance for the study of Love wave in seismic exploration.