High-resolution velocity and strain rate fields in the Kumaun Himalaya: An implication for seismic moment budget

Abstract

The collision between Indian and Eurasian tectonic plates results in a series of earthquakes, releasing stored elastic strain accumulated over a long period. This research utilizes 22 new and 26 previously published GPS velocities along with nine years of InSAR observations to estimate high-resolution velocity and strain rate fields across the Kumaun Himalaya. The resulting high-resolution velocity field ranges between 0.5 and 14 mm/yr relative to the India-fixed reference frame. The geodetic strain rate is not uniform across the study region and the higher strain rates are observed along the Main Central Thrust. The areal change rate along the Kumaun Himalaya indicates a significant amount of tectonic compression, with an average value of − 0.08 μstrain∕yr, while the maximum shear strain rate in the region has a mean value of 0.08 μstrain∕yr. The moment deficit rate, based on accumulated strain and energy release over 200 years, turns out to be 7.59 × 1018Nm∕yr along the Kumaun Himalaya. This suggests that the study region can generate a great earthquake (Mw 8.1) in the future.