Estimation of crustal strain in Kashmir Himalayan region of north India using continuous GPS measurements

Abstract

Global positioning system (GPS) measurements of crustal deformation provide insight into the crustal plate velocity and strain rate variation in the actively deforming Earth's crust. GPS measurements in the Kashmir Himalaya indicate that most of the crustal motion between the Indian Plate and southern China is accommodated along the Himalayan arc, resulting in the accumulation of crustal strain and locking of the Main Himalayan Thrust (MHT). Here, we present geodetically estimated spatial and temporal crustal strain rates in the Kashmir Himalaya from GPS measurements to understand the nature of crustal deformation. We processed and analysed GPS data from 21 sites across Kashmir Himalaya along with several IGS sites. We find that the average deformation rate of the GPS sites in Kashmir Himalaya with reference to the Indian Plate range between 2.8 and 15.5 ± 1 mm/year. The GPS results illustrate that the strain rate field is dominated by a compression component with its rate as 7.2 × 10−8 strain/year and the maximum shear strain, γmax, of 1.9 × 10−7 strain/year. The earthquake focal mechanisms suggest that earthquake activity in the Kashmir Himalaya is predominantly manifested in the form of thrust motion. The maximum principal shear strain value reflects that the Kashmir Himalaya is under NE–SW compressional regime. The spatial distribution of crustal strain indicates that the region north‐east of Kashmir Valley is accumulating maximum strain, resulting in the stress build‐up and could be the region of a future large earthquake.