While earthquakes continue to elude prediction, scientists continue unceasing efforts to assess vulnerability to population and property by intensifying focused studies on earthquake sources and structures at regional and local scales, active fault mapping, paleo-seismological and precursory studies, quantification of ground shaking. CSIR-NGRI is operating more than 170 broadband seismological stations in India for seismological studies and monitoring of earthquakes around Nuclear Power plants. In addition, about 80 educational seismographs under school lab program in the state of Maharashtra.
Updated seismicity maps have been prepared for eastern Dharwar craton and south eastern part of the Deccan Volcanic Province in the Peninsular shield, Doda-Kishitwar of NW Himalaya, NE India and Bhuj region of Gujarat. These studies shall form the basic input in earthquake hazard assessment while laying of gas pipelines (GAIL, Reliance) irrigation/hydro electric power project (Central Water Commission), nuclear power plants (NPCIL). Paleo seismological studies in NE India provide seismogenic liquefaction signatures from the Kopili Fault Zone (KFZ) in Brahmaputra plains of NE India, suggesting occurrence of three large to great seismic events viz. (i) 250±25 yr BP, (ii) between 400 to 770 yr BP and (iii) 900±50 yr BP, in addition to the known historical earthquakes of 1869 and 1943 in this region. The field mapping of active faults is carried out in the Dehra Dun, which is a synclinal valley occurring as piggyback basin in Sub Himalayan mountain front exhuming along the Himalayan Frontal Thrust (HFT). The landforms developed in the valley are repository to the gradational events occurred due to climate - tectonic interaction during the Late Quaternary period. They also bear the evidences front parallel active faulting, which deformed the geomorphic surfaces and lithology developed during the period and preserved the evidence of intra-wedge (MBT-HFT) deformation partitioning in Sub Himalayan mountain front. These active structures have developed in response to repeated earthquake ruptures through time and bear the evidences for the same. Seismological evidence for tearing of the Indian oceanic plate at shallow depths along the Andaman arc, using the shear-wave receiver function technique reveals three distinct plate segments. The middle lithospheric chunk has an abrupt offset of ~20 km relative to the northern and southern segments along the entire stretch of Andaman-Nicobar Islands. It is a key feature that controls plate tectonics and seismogenesis in a subduction setting. Periodic variation of stress field in the Koyna–Warna region of reservoir triggered seismicity has been inferred from focal mechanism studies; a unique 6 station borehole network has been setup there to monitor micro-seismicity.
The seismo genesis of Bhuj region in Gujarat has been studied using the Kachchh seismic network of 11 three-component broadband seismographs, 10 strong-motion accelerographs and four broadband seismographs, which has helped in defining three distinct source zones: the E-W trending north Wagad fault, the E-W trending Gedi fault and the NW-SE trending Banni fault. Besides, there diffused micro earthquake activity is observed along the source region of the 1819 Allah bund (ABF), Island belt (IBF) and Katrol hill (KHF) faults. Detailed analyses of data led to the characterization of the physical properties of the earth’s interior and synthesizing the ground motion for Bhuj due to various seismic sources in this region.
Studies based on source characteristics and P- and S- wave attenuation covering the entire sub-continent indicate non-uniform distribution of the static stress drop along the Himalaya, Burmese arc and the western Indian regions indicates that the central Himalayas are prone to frequent failures owing to the lesser stress drop in contrast with the north-western Himalaya and Burmese arc regions. The results suggest that median stress drops are independent of the earthquake mechanism.
|Dr. Ravi Kumar M||Chief Scientist|
|Mr. Vijaya Raghavan R||Senior Principal Scientist|
|Dr. Shekar M||Principal Scientist|
|Dr. Shashidhar D||Senior Scientist|
|Mr. Naba Kanta Borah||Senior Scientist|
|Dr. Pavan Kumar Vengala||Scientist|
|Dr. Sunil Kumar Roy||Scientist|
|Mr. Solomon Raju P||Principal Technical Officer|
|Mr. Baruah B. C||Principal Technical Officer|
|Mrs. Uma Anuradha M||Senior Technical Officer (1)|
|Dr. Gudapati Suresh||Senior Technical Officer (1)|
|Dr. Srinivas D||Senior Technical Officer (1)|
|Mr. Sanjib Ghosh||Senior Technician (2)|
|Mr. Sarma K. R||Multi Tasking Staff|
|Annapurna B||Multi Tasking Staff|
Page Last Updated On : 13-10-2021