Estimation of shear velocity contrast from transmitted Ps amplitude variation with ray-parameter

Abstract

Amplitude versus offset of P to P reflection is commonly used by the exploration seismology community for hydrocarbon exploration. In this paper, we investigate the feasibility to estimate crustal velocity structure from transmitted P-to S-wave amplitude variationwith ray-parameter. First the transmission coefficient for the plane P wave converting to S wave (P- to -S) is approximated and expressed as a function of slowness. The resulting linear relation involves two coefficients (intercept, X and gradient, Y), which are functions of velocities and densities. Due to the stable nature of X and the fact that P- to -S amplitudes are weakly dependent on the density contrast, we use this parameter next to estimate the shear wave velocity contrast across an interface using the forward scattered P- to -S amplitude versus slowness data.We report on the effectiveness of the approach using various synthetics data sets. The present methodology is also tested on real data sets from two broad-band seismic stations from HYB and COR. © The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society.