Velocity structure in parts of the Gondwana Godavari graben

Godavari graben, a palaeorift on the east coast of India, has been studied to delineate sedimentary thickness and basement configuration. First arriva l seismic refraction data in the Chintalapudi sub-basin of Godavari graben have been utilized for 2-D ray trace modeling. Results indicate a three lay er velocity model, with velocities of 2.3-2.4, 3.2, and 4.0 kms(-1) for the Gondwana (Permian to Cretaceous) sediments. Maximum depth to the basement, of velocity 5.5-5.7 kms(-1), is to about 3 km in the deepest part of the s ub-basin. The basement is possibly the Eastern Ghats suite of rocks. These results are in conformity with the thickness of stratigraphic sequences in a deep bore well in the basin. Another layer of velocity 5.8-6.1 kms(-1) is present at about 4 km depth through out the study region, representing the base of Eastern Ghats Suite of rocks.