15. Radiation from Equivalent Body Forces for Scattering of Surface Waves by a Near-Surface Cylindrical Cavity

The scattering of incident surface waves by a cylindrical cavity of arbitrary shape near the free surface of an elastic half-space is considered in this paper. The scattered field is represented by the radiation from equivalent body forces. The equivalent body forces due to the horizontal and vertical displacement components of the incident surface wave are determined separately. It is found that the equivalent body forces are double forces parallel and normal to the free surface of the half-space. By the use of the elastodynamic reciprocity theorem, the surface waves generated by the equivalent double forces are obtained in terms of properties of the incident wave, the cross-sectional area of the cavity and the elastic constants of the elastic half-space. The superposition of the surface waves generated by the equivalent body forces represents the scattered field of surface waves.