Different techniques (except HVSR method) generally acquire and analyze surface waves in different ways. However, the ultimate aim of the diverse techniques is to determine the surface wave dispersion curve (Rayleigh and / or Love), namely of the distribution, according to the frequency, of the relative propagation velocities associated with the surface waves, possibly analyzed jointly with the surface waves H/V curves In detail, if the wave vibration frequency decreases (increase in the period), the influence of the velocity values of the S waves increases referring to the deeper layers. Then, by suitable inversion procedures, it is possible to define from the dispersion curve to the velocity profile of the S waves until to a depth proportional to the minimum vibration frequency considered in the dispersion curve.