GPS derived crustal velocity, tectonic deformation and strain in the Indian Himalayan arc

Abstract

The present study elucidates velocity of the Indian plate from 2013 to 2016 with the help of six continuously operating permanent Global Positioning System (GPS) stations and tracks the crustal motion and direction directly by means of space-based geodetic measurements. The GPS derived velocity estimates were computed with respect to 2008 International Terrestrial Reference Frame (ITRF 08) and carried out almost all along the arc in the Indian Himalayan Region (IHR). The velocity vectors indicate that the Indian plate is moving towards the NE direction (average velocity of 46.95 ± 0.23 mm/yr) with higher movement towards the eastward direction (36.11 ± 0.17 mm/yr) compared to the northward direction (29.02 ± 0.16 mm/yr). Variations in the plate motion between IISC and permanent GPS stations suggest that presently, the convergence rate is about 8.06 ± 0.28 mm/yr and 5.71 ± 0.17 mm/yr for Higher Himalaya and Lesser Himalaya respectively. In addition, the deformation rate was also calculated on the basis of baseline shortening between IGS stations (IISC and LHAZ) and permanent GPS stations. The results suggest that the deformation is about 11.68 ± 1.32 mm/yr above the Main Central Thrust (MCT) and 6.74 ± 1.20 mm/yr above the Main Boundary Thrust (MBT) with respect to the Indian plate (IISC), while it is 20.60 ± 1.76 mm/yr above the MCT and 11.42 ± 1.21 mm/yr above the MBT with respect to Eurasian plate (LHAZ). The strain rate through GPS measurement reveals that the maximum strain is accumulated in the central part of the Himalaya between the MBT and MCT, indicating vulnerability of the central Indian Himalaya for future earthquakes.