Determination of Poisson's ratio from pre-critical wide-angle seismic reflection data from the BABEL project

S U M M A R Y The pre-critical wide-angle seismic reflection data collected during the BABEL survey using multireceiver spreads contain high-amplitude P-wave and modeconverted S-wave reflected arrivals. The two phases can be partially separated and their signal-to-noise ratio emphasized by exploiting the multifold nature and the increased sensitivity of velocity analysis afforded by these data to produce zero-offset-corrected stacked sections. Using these sections, a method has been developed to derive estimates of Poisson’s ratio by optimizing the cross-correlation of P-wave and S-wave arrivals, and hence to constrain petrological models of the crust sampled by these data. Although the apparently high degree of temporal and spatial resolution of reflected arrivals that are visible within the stacked sections must be reduced to achieve a satisfactory degree of correlation robustness, the results shed some light on crustal petrology, and concur with existing estimates of Poisson’s ratio for the Baltic shield.