Aeromagnetic anomaly map for India: the scientific need

Abstract

Aeromagnetic methods are primarily used for regional geological mapping and in the exploration of natural resources such as oil and gas, minerals, and groundwater. They are also extremely useful in research studies on the internal structure and evolution of the earth, plate tectonics, and earthquakes. Such studies require the potential field aeromagnetic data to be digitally accessible. Aeromagnetic data coverage has already been completed and published for many countries and continents; digitally compiled anomaly maps were prepared and are being used in the exploration and exploitation of natural resources, disaster studies, and research activities. In contrast, India is not entirely covered by aeromagnetic surveying. But certain selected regions covering approximately 70% of the geographic land area of the country were covered with diverse technical specifications and the data is available in a number of disparate individual surveys and flying seasons, tied-up individually to their respective tie-line set up, largely non-digital and poorly archived. The gap areas include the Himalayas, Gangetic plains, Bengal basin, Deccan traps, and Aravalli mountains. The aeromagnetic coverage of these areas is also extremely important with regard to natural resources and hazards. Hence, the gap areas are also required to be covered and the whole data of the country need to be digitally linked together, on top priority, for generating a digitally compiled aeromagnetic anomaly map and database for India. The aeromagnetic data of approximately 48,400 km² of area flown in three different blocks and time periods with varied survey specifications comprising parts of Andhra Pradesh, Tamil Nadu, and Karnataka states of southern India was digitally compiled and is presented.