The data are shown in the figure on the left in the time distance domain and in the figure on the right in the frequency wavenumber (f, k) domain.

We will successively correct the Love wave for its group velocity and then its dispersion by using a phase shift correction. The measurements of the group velocity and of the phase shift allows the computation of the dispersion curves which shows the variation of the phase velocity versus frequency ( figure on the top right).

In the f, k domain (figure on the right), the graphical presentation can be normalized in wavenumber and this allows for better appreciation of the high and low frequencies. The energy is localized in the f, k plane on a curve which can be represented by its tangent to a given frequency.

You can see that, at the dominant frequency of 12 Hz, the f, k curve as a tangent to the vertical line at k=0 (the group velocity is given in m/s therefore the variation between 2 consecutive traces is in sample number).