Tunnel detection using vibrating and impulsive seismic sources with a landstreamer

We present the results of two surveys showing that shear wave seismic reflection can image a sewage tunnel buried at 17 m in marine clay, and coalmine tunnels close to the bedrock surface beneath about 30 m of recent fluvial sediments. The SH shear wave seismic reflection method provides outstanding diffraction features only visible with transverse horizontal sources and recording capacities (H2,H2). These data were acquired using an impulsive or a broader band vibrating source coupled with a landstreamer. The use of SV vertical shear and PP compressive waves extracted from data acquired with vertical vibrating source and receiver mode (V,V) did not give satisfying results for locating tunnels in these environments.