Shallowing of mafic crust and seismic instability in the high velocity Indian Shield

摘要: Indian shield has been frequented by number of large and moderate magnitude damaging earthquakes since historical times, including the recent disastrous ones like Latur Mw 6.3 in 1993, Jabalpur 5.8 1997 Bhuj 7.7 2001. Seismogenesis these events is still not understood well. Detailed study nine such earthquake localities (as appended Table 1), indicates quite high P- S- velocities (6.2–6.7 km/s 3.65–3.90 respectively) at a shallow depth almost surface to six kilometers. These seismogenic regions appear be state continuous uplift erosion geological which brought mafic (granulitic/amphibolitic) crust significantly levels stresses are accummulated due ongoing local input heatflow from mantle. act over above regional compressive generated India-Eurasia collision. As against common belief, role played fluids nucleation earthquakes, relatively denser velocity (compared other global stable continental regions), appears limited.