DETERMINATION OF MOHOROVICIC DISCONTINUITY IN NORTH EAST REGION OF INDIA BY GRAVITY METHOD

Abstract

The mean Bouguer gravity anomaly values over 1° x 10 squares, in the considered region of North-Eastern India, were reduced to smoothed Bouguer gravity anomaly values, using the' influence coefficients derived from vertical components of gravitational effect due to differently positioned 1° x 10 squares at the computation point. The values of these gravitational effects were taken from Cassinis' fundamental tables and also obtained following the procedure based on Newtonian attractions. The computations. based on the use of Cassinis' fundamental tables were separately carried out by the Graphical and Analytical Methods and those based on Newtonian attractions, by the Direct Method. The computed values of smoothed Bouguer anomalies and some of the Airy isostatic anomaly values were utilised in evaluating first, the most probable value o the sea level crustal thickness and then, the depths of , M--discontinuity in the considered region. Depths to the M-discontinuity so computed, as well as the smoothed Bouguer anomaly contours, have then been interpreted in terms of the structures of the North-East Indian litho- sphere.