Research Projects

Northeastern region (NER) of India is a seismically active region which lies in zone V (BMTPC, 2003) of seismic zones of India. The region is wedged in between the Himalayan collision arc to the north and northeast and the Indo Burmese subduction arc to the south and southeast. It has produced two great earthquakes (1897 and 1950) and the whole northeast region experienced 20 large (M more than 7.0) earthquakes during last 200 years (Angelier and Baruah, 2009). It is one of the structurally very complex and tectonically very active regions with the presence of several faults (Nandy, 1986, 2001). Among these faults, the 300-400 km long NW-SE trending Kopili Fault lying over the Kopili –Dhansiri Rivers is a very active fault having complex geology. Concentration of events along both the Kopili Fault is considered to be an intraplate seismotectonic domain. The Kopili Valley region has produced two large earthquakes (more than 7.0) in 1869 and 1943 and Kopili Fault is thought to have triggered the 2009 Bhutan earthquake (Kayal et al., 2012) (Fig. 1). Recently an earthquake of M6.4 with epicenter 9 km NNW of Dhekiajuli, Sonitpur, Assam located at northern part of the Kopili Fault closer to Himalayan Frontal Thrust (HFT) shook the Northeastern region of India on 28 April 2021 at 07:51:25 IST. Thus, this region is identified as a potential region of generating future large magnitude earthquakes. Delineation of extension of the Kopili fault and identification of the most active part through surface mapping are the prime objective towards the estimation of probable maximum credible earthquake. The present study is undertaken towards mapping the active Kopili fault through remote sensing and GIS technique, its probable fault rupture dimension constrained by estimation of slip rate through morphotectonics-neotectonics, seismotectonics and geophysical studies. The integration of these inputs is the prime parameters towards the determination of recurrence period aimed at seismic hazard assessment of the region.