An Implementation Method of the Complex Frequency-Shifted Uniaxial/Multi-Axial PML Technique for Viscoelastic Seismic Wave Propagation

A numerical implementation method of the complex frequency-shifted uniaxial/multi-axial PML (CFS UPML/MPML) is developed for modeling half-space viscoelastic wave propagation. A mixed CFS PML combining CFS UPML and CFS MPML is designed to improve PML's performances in avoiding evanescent waves at grazing incidence and stabilizing long-time simulation of low-frequency viscoelastic wave propagation. Two numerical examples' results showed that the developed method for the mixed CFS PML can implement elimination of evanescent waves at grazing incidence near the PML interface, long-time accurate simulation of low-frequency viscoelastic wave propagation and efficient absorption of the near-fault outgoing seismic waves in homogeneous earth medium.