Post-earthquake landslide hazard evolution: Spatio-temporal analysis of active fault zone in Western Himalayas

Active faults play a critical role in controlling landslide hazards, particularly in orogenic belts such as the western Himalayas, where landslides pose a persistent threat to lives and infrastructure. This hazard became evident during and after the 2005 Kashmir earthquake, which ruptured along the Bagh-Balakot Fault (BBF). This study investigates the spatio-temporal influence of the BBF on landslide distribution from 2006 to 2024 using multi-temporal landslide susceptibility mapping and spatial analysis. Two comprehensive landslide inventories were developed for the pre- and post-decadal periods, LSI-2013 (2006-2013) and LSI-2024 (2014-2024), using high-resolution remote sensing and field validation. Landslide susceptibility was assessed using Logistic Regression (LR) and Random Forest (RF) models, incorporating eleven conditioning factors screened for multicollinearity using Pearson correlation and VIF analyses based on a 70/30 split of landslide and non-landslide points into training and testing datasets. The results indicate that the RF model consistently outperformed LR, achieving higher predictive accuracies with area under the curve (AUC) values of 0.91 (LSI-2013) and 0.90 (LSI-2024). Maximum landslide densities of 4.0 and 2.2 landslides/km² were recorded within the 0-250 m and 250-500 m buffers of the BBF, respectively. This pronounced localized clustering remains significantly higher within 1 km along the BBF across both temporal inventories, underscoring the long-term geomorphic influence of fault activity, particularly along its northern segment. In contrast, areas distal to the fault exhibit an overall temporal decline in landslide susceptibility from 2013 to 2024, reflecting progressive post-seismic slope stabilization following the 2005 earthquake. The multi-temporal landslide susceptibility maps clearly demonstrate the persistent fault-controlled susceptibility patterns and evolving nature of landslide hazard in this region. Ultimately, this study provides comprehensive site-specific spatial guidance for landslide hazard assessment and offers insights for informed land-use planning and risk mitigation in tectonically active regions of the western Himalayas.