Strain Accumulation and Release in the Himalaya from ALOS-2 InSAR Analysis

We study the active Himalayan deformation via examining the interseismic, coseismic, and postseismic phases, exploring the strain on the Main Himalayan Thrust due to Indian and Eurasian Plate convergence. We examine postseismic deformations resulting from the 2015 M7.8 Gorkha Earthquake, employing InSAR data, ALOS-2 L-band, from the JAXA ALOS-2 SAR satellite. InSAR in the Himalayas is challenging due to the extreme topographic relief, steep slopes, vegetation and snow cover, and L-band is an advantage. We focus on the phase unwrapping, topographic, tropospheric, and ionospheric corrections to improve the InSAR time-series. The final interseismic results provide information on the evolution of the strain field. Initial results from the 2015-2019 Gorkha postseismic analysis are consistent with afterslip down-dip from the 2015 rupture and absence of afterslip on shallower megathrust. This approach sets the stage for future analyses of data from the forthcoming NISAR mission, with enhanced ionospheric and tropospheric corrections.