Crustal Velocity Structure of the Indian Shield from Deep Seismic Sounding and Receiver Function Studies

The average crustal velocity and Moho depth, estimated from the data of more than 5000 km deep seismic sounding (DSS) profiles and a number of broadband seismological stations covering various geological and tectonic units of the Indian shield have been presented. The average crustal velocity varies from 62 to 65 km/s except at few anomalous regions. The average crustal thickness varies from 40 to 42 km except in Dharwar craton (35-45 km) and southernmost part of the southern granulite terrain (35-38 km). The crust is thinner towards both eastern and western coasts of the shield. The crust to the north of the west coast is again thinner (-25 km) than that of the east coast (-35-37 km) with a prominent up-Warp at the eastern flank of the West-Bengal Basin (-30-32 km). The shallowing of the crust towards the coast is due to underplating and breakup of the Indian shield from the Gondwanaland.