Tectonics and thermal structure of western Satpura, India

Increased seismicity and occurrences of hot springs having surface temperature of 36-58 °C are observed in the central part of India (74-81° E, 20-25° N), where the NE trending Middle Proterozoic Aravalli Mobile Belt meets the ENE trending Satpura Mobile Belt. Earlier Deep Seismic Sounding (DSS) studies along Thuadara-Sendhwa-Sindad profile in the area has showed Mesozoic Sediments up to around 4 km depth covered by Deccan Trap and the Moho depth with a boundary velocity (Pn) of 8.2 km/s. In the present study, surface heat flow of 48 ± 4 mW m−2 has been estimated based on Pn velocity, which agrees with the value of heat flow of 52 ± 4 mW m−2 based on Curie point isotherms estimates. The calculated temperature-depth profile shows temperature of 80-120 °C at the basement, which is equivalent to oil window temperature in Mesozoic sediments and around 570-635 °C at Moho depth of 38-43 km and the thermal lithosphere is about 110 km thick, which is comparatively higher than those of adjoining regions. The present study reveals the brittle-ductile transition zone at 14-41 km depth (temperature around 250-600 °C) where earthquake nucleation takes place.