Identifying the Transition Zone Between East and West Dharwar Craton by Seismic Imaging

Abstract

The data from 12 temporary broadband seismic stations operated across east–west corridor in Dharwar region of Indian Peninsula along with ten other seismic stations operated by CSIR National Geophysical Research Institute (NGRI) in the region have been analysed that provide high-resolution image of southern Dharwar crust. Crust along the corridor is imaged by receiver function $$H-k$$ stacking, common conversion point stacking using data from 22 sites in combination with joint inversion modeling of receiver functions and Rayleigh wave group velocity dispersion curves. The velocity image reveals thinner crust (36–38 km) except one site (coinciding with Cuddapah basin on the surface) in East Dharwar Craton (EDC), while crust beneath the West Dharwar Craton (WDC) is thicker (46–50 km). This study also observed a transition zone between EDC and WDC starting west of Closepet granite to the east of Chitradurga Schist Belt (CSB), which shows diffused Moho with a thickness of 40–44 km. Chitradurga Schist Belt is identified as the contact between Mesoarchean (WDC) and Neoarchean (EDC) crustal blocks. The lowermost part of the crust ( $$V_\mathrm{s} > 4.0$$ ) is thin (2–6 km) beneath EDC, intermediate (6–8 km) beneath transition zone and thicker (14–30 km) beneath WDC across the profile.