Seismic Wave Propagation in Elastic-Viscoplastic Shear Layers

A computational method is introduced for simulating seismic wave propagation in elastic-viscoplastic shear layers. The fundamental dynamics are expressed by two partial differential equations for shear stress and velocity, the balance of momentum, and the elastic-viscoplastic constitutive law. They are converted to those for the upward and downward components of horizontally-polarized motion and then a finite difference method is applied. Seismic wave propagation is computed, considering the reflection and refraction rule at the contact boundary of two layers, as well as the boundary conditions at the bottom and top. Simulation analyses for the observed records show that the proposed method is effective and practical, although it cannot simulate liquefaction phenomena.