A tomographic image of upper crustal structure using P and S wave seismic refraction data in the southern granulite terrain (SGT), India

We present a 2-D tomographic P and S wave velocity (V-p and V-s) image with V-p/V-s ratios along N-S trending 220 km long deep seismic profile acquired in 2005, which traverses across major shear and tectonically disturbed zones in southern granulite terrain (SGT), India. The 2-D velocity model constrained down to maximum 8 km depth shows velocity anomalies (>0.2 km/s) beneath major shear zones with good spatial resolution (>0.05 km/s). The presence of high V-p (6.3-6.5 km/s), V-s (3.5-3.8 km/s), V-p/V-s (>1.75) and Poisson's ratio (0.25-0.29) indicate significant compositional changes of rocks at shallow depths (0.5 to 8 km) reveal rapid crustal exhumation of mid to lower crustal rocks. This crustal exhumation could be responsible due to Pan-African tectonothermal activity during Neoproterozoic period.