The Hilbert transform has 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 raw VSP section , the down going waves, the down going P waves. 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 down going P-waves, the stacked amplitude, normalized by the maximum value and expressed in dB, represents the attenuation of the medium.