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The Kumaun Himalaya is considered as the most active part of the Central Seismic gap in the Indian Sub-continent. In this paper, we presented active surface deformation rates of the Kumaun region from February 2017 to February 2021 using the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) technique. The cumulative displacement that occurred during the span of 4 years is ±55 mm, whereas the Line of Sight (LOS) deformation velocity rate ranges is ±7 mm/yr. Apart from PSI, we also estimated the b-value of the Kumaun region from 1803 to 2021 (399 events) and its value is 0.54 ± 0.03. A distinct NE-SW trend of b-value is observed where earthquakes with M>6 occurred towards NE of this trend. The PSIderived deformation reveals that the central part of the Inner Lesser Himalaya along with the Main Central Thrust (MCT) zone is dominated by uplift. The zone between the Munsiari Thrust (MT) and MCT in the central region shows the maximum uplift ranging 5-7 mm/yr which exactly lies above the mid-crustal ramp of the Main Himalayan Thrust (MHT). Our results are well corroborated with available observations of geodetic strain and peak ground acceleration values. However, the deformation patterns and highvelocity rates in the central part of the study area between MT and MCT indicate the accumulation of high stress. [ABSTRACT FROM AUTHOR]

Remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR), have the potential to document and monitor surface deformation up to a millimetre scale especially in areas where ground monitoring is not feasible. The InSAR technique has been used to isolate and map some current and potential landslide areas in Kinnaur region of the Satluj Valley in Himachal Pradesh. The fragile ecosystem of Kinnaur has been challenged by the shifting climatic pattern and immense anthropogenic pressure associated with burgeoning hydroelectric projects, leading to destructive landslides of epic proportions. Three recent landslides that occurred at Ribba and Pangi villages of the Satluj River Valley and the Batseri landslide in the Sangla Valley were studied and potential landslide areas along the Satluj Valley were mapped with Sentinel-1 multi-baseline interferograms using data acquired between 2016 and 2021. The analysis suggests significant changes in velocities (±11 mm/y) where the subsidence rate ranges from −6 to −11 mm/y with a cumulative displacement of ±45 mm/y. Our study highlights the potential locations for future landslides and provides an early warning landslide map to support future disaster prevention in highly deformed regions. [ABSTRACT FROM AUTHOR]