Imaging of the Weathered Zone and Estimation of Q in Sediments

Phase-consistent filtering together with frequency time analysis (multiple filtering) is used to obtain the group velocity dispersion curve of the fundamental mode and first few higher modes of Rayleigh waves from seismic exploration data. The group velocities are then inverted to obtain the shear wave velocity distribution to a depth of about 30 meters. Comparison of the experimental traces with the complete synthetic seismograms, computed using structural parameters of the inversion results as input, allow us to estimate che anelastic properties of the medium: Q (quality factor) values are observed to vary from 5 to 20.