Geomorphic signatures of active tectonics in the Poonch basin, Northwestern Himalaya, India

The Poonch Basin, situated in the tectonically active northwestern Himalaya, represents an ideal natural laboratory to evaluate geomorphic responses to ongoing crustal deformation. This study integrates geological mapping, morphometric analysis, and geospatial techniques to assess active tectonics and landscape evolution across nine sub-watersheds of the basin. Stratigraphic succession from Precambrian Salkhala metamorphics to Tertiary Siwalik sediments reflects a long history of thrust propagation and folding, influenced by the Panjal and Murree thrust systems and the Hazara–Kashmir syntaxis. High-resolution digital elevation models (DEMs) were employed to extract drainage networks and compute morphometric indices, including bifurcation ratio, drainage density, hypsometric integral, ruggedness number, and stream-length gradient indices, supplemented by longitudinal profile analysis and lineament mapping. The results reveal strong structural control on drainage organisation, with elongated sub-watersheds, steep slopes, and high relief values. Knickpoints, anomalous bifurcation ratios, and asymmetric drainage alignments indicate active uplift and tectonic forcing. Hypsometric curves suggest that most sub-watersheds are in youthful to mature evolutionary stages, while variations in slope–area relationships reflect differential erosion and lithological resistance. Relief indices, including ruggedness number and Melton’s ratio, confirm moderate-to-high erosion potential, particularly in upper catchments. Collectively, the morphometric evidence demonstrates that the Poonch Basin is tectonically active, with neotectonic processes strongly influencing valley morphology, drainage evolution, and sediment dynamics. The study presents the first quantitative framework to interpret regional tectono-geomorphic evolution in this sector of the Himalayas and provides vital information to inform hazard assessment, hydrogeological planning, as well as sustainable management of this geologically fragile sector.