Absorbing Boundary Conditions for Rayleigh Waves

The first-order absorbing boundary conditions for elastic waves are transparent for P and S waves at normal incidence, but give rise to parasitic reflections of Rayleigh waves. To treat these phenomena, a solution of geometric type is proposed that eliminates these parasitic waves but causes others to appear, which, while less important, are still troublesome. A second solution is proposed by constructing a new condition of second-order type, transparent for P and S waves at normal incidence as well as for Rayleigh waves. This condition is analyzed mathematically and its good behavior is demonstrated with regard to reflection phenomena.