Direct interpretation of surface waves for 2-D and 3-D subsurface imaging

The soil stiffness is routinely evaluated by direct investigation, using geotechnical tests such as CPT-CPTu, SPT. While this approach allows retrieving detailed and reliable information, the procedure is invasive and the result is punctual hence of limited spatial extension. In what follows we shall establish a strategy that can be used both as a feasible inversion strategy or alternatively for the direct interpretation of active source datasets. Following the second course, we shall show that the Direct Interpretation of Phase Lags (DIPL) which uses the frequency-dependent phase lags among pairs of seismic signals, is capable of retrieving a satisfactory 2-D and 3-D shear wave velocity subsurface image also in complex subsurface environments without the need of inversion.