Numerical Modeling Of Seismic Wave In Viscoelastic Media

The propagation of seismic wave exists many differences in real media and ideal media.The viscosity of medium call dissipate energy of seismic wave and amplitude,decrease the apparent frequency.So it is hard to obtain detailed subsurface information and high resolution image directly.This anelastic behavior of real earth media can be described well by a viscoelastic model.In this paper,the numerical simulation method of viscoelastic model and the law of attenuation about seismic wave were mainly researched and studied.In this paper,absorption and attenuation of seismic wave in viscoelastic media have been analyzed from the theory through viscoelastic wave equation which were derived from the basic concept of viscoelastic media.The elastic wave equation in 2-D Kelvin viscoelastic media was solved by the finite difference method of higher order,which achieved the numerical simulation of seismic wave in viscoelastic media.In the numerical simulation,an improved attenuation factor was introduced to the attenuation boundary conditions,the result proves that new attenuation factor is more effective than the old one and the edge reflection was more thoroughly extinguished at the same width of attenuation zone.Common used the full elastic wave equation to carry out the numerical modeling of elastic wavefield only obtained a hybrid wavefield of P-wave and S-wave.Based on the previous research,the paper gave an equivalent equation of full viscoelastic wave equation,which contains variations of both the hybrid wavefield and the pure P-wave and S-wave wavefield.Using the finite difference method of higher order to solve the wave equation,obtained totally separated wavefield of pure P-wave and S-wave while obtaining hybrid wavefield,and preserved the information of mutual transformation of P-wave and S-wave energy.The analysis of modeling wavefield showed using numerical modeling of viscoelastic wave separation has important meaning in respect of knowing the propagating rule of seismic wave in viscoelastic media.