EngGeo1 Experience of Borehole Seismic Surveys by Method of Reversed Vertical Seismic Profiling

At designing of especially responsible constructions, such as NPP, high-rise buildings etc., reception of detailed data about velocities of longitudinal and shear waves in layers on depth up to 100-120 m is required. Ground seismic methods in such cases cannot be reliable and sufficient detail of researches on such depths. As the basic method here it is necessary to apply method VSP (Vertical seismic profiling, 1984). However a number of condition is necessary for reception of the qualitative information: casing borehole with a pipe of one diameter, cementation of space behind a pipe, careful washing of a hole, use of probes by a special design to provide a good clip to walls of a pipe. Often for the objective reasons it is not possible to reach necessary results. In these cases combine classical VSP and torpedoing of boreholes are useful.