The nature of free-air, bouguer and isostatic anomalies in southern peninsular India

Abstract

The relationship between elevation and gravity anomalies over Southern Peninsular India is examined with the help of free-air and isostatic anomaly maps and 1° × 1° average elevation and free-air and Bouguer anomaly maps. Free-air anomalies are directly related to the topography while isostatic anomalies are independent of the same, which indicate that isostatic balance is achieved on a broad scale. In both the maps, gravity anomalies along the west coast contrast with those along the east coast. This may indicate contrasting crustal conditions near and off the two coasts. 1° × 1° average maps proved to be effective filters in removing the local topographic features and their gravity effects and bring out a close relationship between regional elevations and regional gravity anomalies. Station elevation—gravity anomaly relationships along profiles suggest that most of the elevated hill masses of South India are regionally compensated.