Joint use of seismic surface waves and multioffset GPR for sandy soil characterization

We used shallow seismic surface waves and multioffset ground penetrating radar (GPR) to investigate the vadoze zone at a sandy soil site in Grugliasco (Turin), Italy. The two geophysical methods yielded coincident high resolution imaging of the upper six meters of the subsurface. We identified three distinct horizons along a GPR common offset profile and corresponding shear wave and radar wave velocity profiles. Seismic surface wave velocities are sensitive to soil shear strength whereas radar velocities are related to soil volumetric water content. Joint use of the two methods provided complementary information about lithology and soil water content of the vadoze zone.