The Hilbert transform has been applied to the different wave fields in order to estimate their amplitude with the instantaneous envelope computed from the associated analytic signal.

The video shows the instantaneous amplitude of the down going Stoneley waves, the up going Stoneley waves and the residue, named here Noise. For each wave field, the instantaneous amplitudes are stacked in a corridor immediately following the arrival time of the down going P-wave. For the Stoneley waves, the stacked amplitude, normalized by the maximum value and expressed in dB, represents the conversion of a body P-wave in to a Stoneley mode. For the residue, the stacked amplitude represents the attenuation of the down going wave field.

We can notice for the up going Stoneley mode a high value of the conversion factor at a depth of 55 meters which corresponds to a water productive karstic layer.