A number of researchers have demonstrated the usefulness of surface acoustic waves (SAWs) as a means of evaluating crack size and investigating crack opening during fatigue crack growth. Rayleigh waves can be used to measure changes in depth of cracks beneath the surface in advanced engineering materials [1–3]. Recently, the crack growth behavior and the crack length distribution of a distribution of surface breaking fatigue cracks have been experimentally studied [4], and a simulation technique for the crack length distribution has been proposed.