The paper presents results of recognizing the failure surface of a landslide from the Carpathian flysch by means of the GPR and seismic surveys. GPR antennas with different frequencies: 400, 200 and 50 MHz were tested. The seismic survey (refraction profiling combined with 1D MASW technique) was employed to evaluate the resolution of P-wave and S-wave in that conditions. The measurements were designed basing on earlier geological engineering recognition and numerical stability analysis of the landslide. As a result, optimal parameters for GPR and seismic surveys in the Carpathian flysch conditions were chosen.