Neotectonic fault movement and intraplate seismicity in the central Indian shield: A review and reappraisal

The central Indian shield area is characterized by earthquakes with dominantly oblique – reverse movements on pre – existing faults along paleo – rift zones. These earthquakes, occurring hundreds of kilometers away from the plate boundary, are considered as Stable Continental Region (SCR) earthquakes. In this contribution, we have attempted to analyze the nature of intraplate earthquakes of the central Indian shield with special reference to the Son – Narmada – Tapti (SONATA) zone which is known as a paleo – rift with Precambrian ancestry and a proven geological history of repeated tectonic rejuvenation throughout the Phanerozoic. The cause of the neotectonic fault movements, the paleo – seismic records and the seismic history of the SONATA zone are discussed in detail. Geological, geophysical and heat fl ow measurement data suggest stress concentration in the SONATA zone in response to the far – fi eld plate boundary forces arising out of the Indo – Tibetan plate collision in the north (Himalayas), which causes intraplate earthquakes in this tectonically stable region. A review of the present state of knowledge on the tectonically active areas in the central Indian cratonic area is presented here. We have also attempted to give an appraisal of the tectonic reactivation of pre – existing rift – related faults under the neotectonic stress fi eld, using new data from our analogue experimental work.