Estimation of the P-Wave Velocity of the Near Surface Using Dispersion Analysis of the Guided P-Wave

We use the dispersion property of the guided P-wave to obtain a P-wave velocity model of the near surface. To calculate the phase velocity of the fundamental mode of the guided P-wave for any given geophone location (here called central geophone), we consider an array of geophones where the central geophone was in the middle of the array. The length of the array (aperture) was assumed to be one to one and half times of the maximum wavelength of the guided P-wave to ensure high lateral resolution of the estimated phase velocity. We invert the estimated phase velocity to a P-wave velocity model through inversion. Then, we compared our estimated P-wave model to a P-wave velocity model obtained from the refraction method. Although the two models relatively show the same trend, the P-wave velocity model from the guided P-wave exhibits some details that are absents in the refraction results. With respect to our results, it is possible to create a high resolution P-wave velocity model of the near surface by using guided P-waves.