Slipping interfaces: A possible source of S radiation from explosive sources

We consider the problem of reflection and refraction of purely compressional waves incident on an interface separating identical solid half-spaces in which the condition of continuity of shear displacement at the boundary is generalized to one that allows slippage. The problem is solved using the Cagniard-de Hoop technique. It is found that the generation of reflected P and S waves, as well as transmitted S waves, is most effective in the case of perfectly unbounded half-spaces. We discuss the implications of this model for the generation of S waves by block movement in the vicinity of an underground explosion.