Seismic velocities in the Bengal basin

In the last 20 years a considerable number of seismic lines have been acquired in different parts of Bangladesh. Velocity informations are available from most of these lines, and in this study a systematical analysis of the velocity distribution is done by applying Dix' formula on reported stacking velocities. We find in sedimentary rocks of the area the average P-velocity values to be about 1.65 km/s at surface, increasing to 2.5 km/s at 1 kms depth, 3.3 km/s at 2 km, 3.9 km/s at 3 km, 4.35 km/s at 4 Km, 4.7 km/s at 5 km, and 5.0 km/s at 6 Km depth. Small, but systematical regional variations are found, which seem to be related to lithology and various tectonic activity in the region