Crustal deformation studies in Jammu Himalaya using PSInSAR technique

Abstract

The Jammu Himalaya lies within the deformation zone affected by the 1905 Kangra and 2005 Kashmir earthquakes, where continuous micro-seismic activity has been observed. To understand the patterns of active crustal deformation, Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) and stream power law equations have been applied to analyse the brittle crust of the Tawi Basin in the northwestern Himalaya. The PSInSAR-based results reveal that from 2017 to 2020, the region experienced active surface deformation with a mean velocity of +16 to −18 mm/yr and a standard deviation of 0–5 mm/yr. These rates align with previous Global Positioning System (GPS) base geodetic arc normal observations (11.2 ± 3.8 mm/yr to 14 ± 2 mm/yr) in the northwest Himalaya. The PSInSAR data show Line of Sight (LoS) displacements ranging from +45 mm to −50 mm, with negative values indicating tectonic subsidence, mass wasting, and erosion, while positive values suggest uplift and sediment deposition. The LoS displacement varied between −50 mm and +40 mm to the south and north of the Mandili-Kishanpur Thrust (MKT), respectively, and these values are consistent with the observed Gradient Length Anomalies (GLA). Crustal deformation is notably high in the hilly and mountainous regions, with knickpoint analysis indicating that uplift associated with crustal shortening contributes to the development of knickpoints. Further, the Tawi river basin in the northwestern Himalayan region is prone to landslides, with high steep slopes in the northern part of the Main Central Thrust (MCT) and Main Boundary Thrust (MBT) zones, being particularly vulnerable, and footwall subsidence to the south potentially linked to active thrust faulting.