Seismological and geophysical studies of NW Himalaya: tectonic implications

Abstract

The NW Himalaya (30°– 33°N, 76°–80°E) originated due to the continuing India-Eurasia continental convergence since Cenozoic time (~55 Ma) is largely believed to be multifaceted tectonic processes including earthquakes, landslides and other natural occurring disasters in different times, some on annual basis and others at unpredictable times . The complexity in the geodynamic evolution of the Himalaya region had experienced series of earthquakes of which 553 number of the earthquakes having an intensity range from II to X on Modified Mercelli (MM scale) occurred in the study region (30°– 33°N, 76°–80°E) in the last 50 years. This NW Himalaya region covering the two major states especially Uttarakhand and Himachal Pradesh of Northern India is placed in Seismic zone 4 and Seismic zone 5 in the hazard zonation map of India. Therefore the complexity involving different intensity of earthquakes, periodic seismic tremors reveal the continuous active tectonic process has been operational over the entire region covering an area of 1,09,156 sq. km. The present study using a combined geophysical techniques of both gravity and seismological tools is an attempt to unravel secrets of active tectonism. This research based on the methodological advantage of uninterrupted monitoring of active geophysical data, attained by the national institute of global importance, WIHG, Dehradun, is to support geophysical research investigations to a better academic and research.