The authors discuss applicability of phase characteristics of surface waves in monitoring of underground openings and tunnels. The mathematical model of surface wave propagation along extended cavities is presented. The properties of the numerical solutions obtained using the model are analyzed, including the amplitude and frequency characteristics, and the phase and group velocities of the waves. It is possible to recover elastic properties of a medium using the dispersion curves of the phase velocities. The data of numerical modeling of surface wave propagation along cavities of different geometry using the method of finite spectral elements are presented. The calculated results of the axisymmetrical and three-dimensional problems of surface wave propagation along cavities are studied.
