A recently developed multiple scattering formalism is applied to treat scattering of elastic waves by subsurface defects. In particular, the problem of a spherical cavity near a stress free surface is considered. The spherical cavity is viewed as one scatterer, and the stress free plane (reflector) as the second. The solution to the sub-surface cavity is then represented as an expansion in the two scattering processes. This expansion is truncated after a finite number of terms; namely, only processes that include single scattering by the sphere are kept. The multiple scattering formalism is reviewed, and physical interpretation of the various terms in the expansion is presented. Then the contribution of each term is expressed in terms of scattering amplitudes of a spherical cavity in an infinite medium and the reflection coefficients of a stress-free planar surface. The results are summarized in terms of graphs of scattered amplitude as a function of frequency and scattering angle. An example of titanium testing is presented.