Continuous GPS measurements of crustal deformation in Garhwal-Kumaun Himalaya

Abstract

We report GPS measurements of crustal deformation from five continuous sites in the Garhwal Kumaun Himalaya. The motion at these sites confirms strain accumulation on the Main Himalayan Thrust (MHT) under the Outer and Lesser Himalaya with a slip deficit rate of 18 mm/year over a width of ∼100 km. Apart from secular plate motion, these sites also exhibit seasonal variations. We model these seasonal variations using the global models of atmospheric and hydrological loads. The influence of these loads is maximum in the vertical component which decreases in the north and then in the east component. All the four sites in the Himalayan region and a site at Delhi show consistency between the observed seasonal variations with that predicted by the model. However, the annual variations in the horizontal component of displacement time series at BDRI (Badrinath) GPS site are not consistent with the predictions which could be due to local site conditions.