Morphometric Analysis in Relationship With Landslide Distributions in the Tons River Basin in the <scp>SE</scp> Part of the Western Himalaya

ABSTRACT Hillside instability is a serious problem in the Himalaya, making it decisive to identify the landslide‐prone areas and comprehend their failure mechanism. This study utilises remote sensing and morphometric approaches along with available geological data to comprehend the distribution of landslides in the TRB in the western Himalaya, India. The study found that a total of 702 landslides has occurred in the basin and 45.01% of these landslides exist in the terrain shaped by the Jutogh Group, all occurring along valleys, roads, and settlements, being primarily driven by anthropogenic forcings. Likewise, the Deoban, Chandpur, Ramgarh, Chakrata, and Berinag formations experienced 120, 131, 66, 64, and 5 landslides, accounting for 17.09%, 18.66%, 10.22%, 9.11%, and 0.7% of the total landslides in the basin, respectively. Morphometric results suggest that the majority (32.14%) of landslides occur in regions characterised by low to moderate drainage densities, and there is an uneven distribution of erosion potential among the sub‐basins, having different lithologies and slope morphologies. The results further suggest a narrow valley floor ( V f ) of TRB, with V f and stream length ( S L ) gradient index variable spikes at infrequent distances from the source, being highest toward upstream parts in the Jutogh Group. In addition, the steepness index ( K sn ) corresponds to the S L index, having maximum spikes at 122.5 km. The study reveals that a high density of lineaments and erosional potential is observed in country rocks of the Jutogh Group and lowest in Nagthat and Chandpur formations, and landslides are not confined to the range of the slope gradients but distributed at various slope classes.