Tectono-geomorphic and active deformation studies in the Ujh basin of Northwestern Himalaya

Abstract

This study focuses on the morphotectonic analysis of the Ujh River basin, examining various aspects related to geometrical changes in the drainage basin caused by tectonic and erosional processes. The topographic development of the Ujh River basin is a response to enhanced tectonic deformation caused by Main Central Thrust (MCT) and Main Boundary Thrust (MBT). We assume that the basin asymmetry, tilting, incision, and migration of the river basin are regulated by the compressive force generated between MBT and MCT. The results were characterized by a high Asymmetry Factor (Af) indicating greater asymmetry suggesting a rightward tilting with low Valley Floor to Valley Width (Vf) values which indicate differential uplift and incision owing to ongoing tectonic processes. The high Stream Length Gradient (SL) Index values in the MCT zone, indicate sudden topographic breaks caused by the vertical tectonic uplift with active erosion processes. The Ujh River basin is in a disequilibrium state, with convex portions indicating uplift and concave portions indicating subsidence on the slope-area plot. The χ analysis, plotting χ values against elevation, highlights upliftment and erosion zones along the trunk stream, with major slope breaks and high χ values observed in the upstream region, particularly along the MCT. Overall, the Ujh River basin exhibits morphotectonic characteristics indicating ongoing tectonic activity and a state of disequilibrium.