The electrical resistivity and seismic velocity distributions over a buried hillside have been obtained using non-invasive controlled experiments on coincident profiles and 2D image reconstructions. The optimal images are in structural agreement and allow the deduction of two opposite resistivity-velocity trends in the near-surface materials. For both trends, the resistivity (ρ) and p-wave velocity (Vp) are related in the form Log10 ρ = mLog10Vp + c with the respective constants m and c having different signs in unconsolidated and consolidated materials.