The displacement caused by a source on an interface between two solid semi-infinite elastic media presents an excellent study in interference between direct, head and interface waves. The solution herein derived provides fresh insight into the nature of pseudo-Stoneley interface waves. As well, the evolution of the head and direct waves is discerned as they move away from the interface.
The technique used to solve the problem demonstrates the simplicity of using Sherwood's (1958) method with generalized ray theory. The displacement is simply expressed in a closed form which can be rapidly evaluated and is straightforward to interpret physically.