Solid particle motion induced by a point source above a poroelastic half-space

By using a modified Biot model of the poroelastic half-space and the classical approach to determination of the field at a fluid/solid boundary, the wave contributions to the solid surface particle velocity due to a point source in air above an air-filled poroelastic solid are identified and evaluated. The evaluation involves both a new method of approximation of the branch-cut integrals and the light fluid limit when searching for surface-wave modes. The significant contributions are found to be from the direct and ground waves in air and from a surface wave which may be described as an air-coupled Rayleigh wave. The parameter combination that maximizes the air-coupled Rayleigh-wave contribution is identified.