Integrated landslide hazard, vulnerability, and risk mapping in Srinagar region of Uttarakhand, Lesser Himalayas

Landslides are a life-threatening hazard in mountainous regions, particularly in tectonically active terrains like the Himalaya. The Srinagar region of Uttarakhand experiences frequent landslides, generally due to unplanned urbanisation, active tectonics, heavy rainfall, and fractured lithology. The present study aims to produce landslide hazard, vulnerability, and risk maps of the study area using bivariate statistical approaches in a GIS environment. Two statistical models, frequency ratio (FR) and information value (InV) models, were applied to generate landslide hazard maps. FR model classified 18.88% (13.14 \:km² ) and 4.87% (3.39 \:km² ) of the area as high and very high hazard, respectively, while InV model identified larger extents of 28.66% (19.95 \:km² ) and 16.02% (11.15 \:km² ). High and very high vulnerability covered 8.27% (5.85 \:km² ) and 1.28% (0.91 \:km² ) of the area, individually. The FR-based risk map delineated 21.14% (14.72 \:km² ) as high and 3.71% (2.58 \:km² ) as very high, while the InV-based risk map identified 18.65% (12.98 \:km² ) and 4.33% (3.01 \:km² ) as high and very high, separately. The efficiency of the models was validated using ROC curves and field-based observations along with kinematic analysis of a potential slope. The prediction rate curve shows that the InV model (AUC = 0.783) performed slightly better than the FR model (AUC = 0.734). The success rate curve shows AUC values of 0.827 and 0.885 for the FR and InV models, respectively. In addition to ROC-AUC validation, field-based observation of landslide events and kinematic analysis of a potential slope shows wedge mode of failure which confirm the reliability of the results.