The Geological Survey of India brought out a Publication entitled Seismotectonic Atlas of India and its Environs, authored by S. Dasgupta, P. Pande, D. Ganguly, Z. Iqbal, K. Sanyal, N.V. Venkataraman, S. Dasgupta, A. Roy, L.K. Das, P.S. Misra and H.K. Gupta under the editorship of P.L. Narula, S.K. Acharyya and J. Banerjee in the year 2000. It comprised 43 number of SEISAT sheets on scale 1:1 million. The geographic base in this publication was taken from the International Map Series prepared by the Survey of India and tectono-stratigraphic base generated from various thematic maps published by the GSI. The geophysical, structural and geothermal data relevant to seismotectonics were superposed over the base maps. In this paper version, the earthquake information pertained to a period upto 1993. Initial digitisation of the analog atlas was done in collaboration with NIC and later reformatted, scrutinised and validated by Geodata Division, CHQ, GSI.

The Atlas proved to be of great utility to various stakeholders, particularly those engaged in studies related with seismic hazard assessment and seismotectonic evaluation. There was, however, a growing demand for updation of the Atlas database and conversion into a digital format so as to make it more user-friendly. Keeping these requirements in view, the Geodata and Database Division, Central Headquarters, Kolkata under Mission-III has made efforts to bring out a Digital Version of the Atlas in projection Lambert Conformal Conic, Datum-WGS 1984, Spheroid-WGS 1984 and Unit-degree. The epicenters of 19,504 earthquakes of magnitude (Ms/mb) >= 4.0, pertaining to a period from 1897 to 2009 and compiled from various catalogues such as ABE, BCI, CFR, CGS, GR, ISC and USGS-NEIC, have been used in it. The Fault Plane Solutions of 1292 important events of Mw >= 4.6 that occurred during the period between 1977 and 2009 have been obtained from HRVD source [www.seismology.harvard.edu]. The faults in the Atlas have been categorized on the basis of tectonics and seismic activity. The Bouguer Gravity contours in the land surface and Free Air Gravity counters in the Sea have been presented in mgal. Depth of crystalline basement below the Sediment and Deccan Trap cover, the Moho depth and bathymetry contours have also been given. Read More