This article describes a method to detect and control low-velocity intercalations in rock mass in neighborhood of tunnels and underground mine workings using calculated phase velocities of surface seismic waves. Initial data are synthetic seismograms from numerical modeling of radially symmetric propagation of seismic waves along a mine working. It is shown that overlapping of a low-velocity heterogeneity in rock mass by a higher velocity layer brings no obstacles to the identification of the heterogeneity by the proposed method. Observations over phase velocities of surface seismic waves make it possible to assess rock mass adjacent to underground structures, which is a relevant result from the practical point of view.
