Comparative multi-criteria decision-making approaches for landslide susceptibility mapping in Khagrachhari district of southeastern Bangladesh

Landslides have become common and destructive hydrogeological hazards in the southeastern hilly regions of Bangladesh, particularly in the Chittagong Hill Tracts (CHT). This is due to the unstable geology, intense monsoon precipitation, and unregulated human activities. Khagrachhari has been recognized as a significant landslide hotspot in the CHT; however, insufficient research has been conducted on spatial risk modeling and evidence-based mitigation planning. This study intends to create a detailed landslide susceptibility map of Khagrachhari through a hybrid multi-criteria decision-making framework that combines the Analytical Hierarchy Process (AHP) and the Analytical Network Process (ANP) within a GIS environment. A comparative analysis was performed utilizing both models, integrating high-resolution spatial datasets and assessing thirteen natural and anthropogenic factors affecting slope instability. Factor weights were assigned using expert-driven pairwise comparisons (AHP) and network-based interdependencies (ANP), while susceptibility maps were produced and validated using established landslide inventory points. The findings indicate that both models effectively identify high-risk areas, specifically in Matiranga, Mohalchari, and Guimara, with strong predictive performance demonstrated by AUC values of 0.839 (AHP) and 0.828 (ANP). The ANP model, however, provided smoother spatial transitions and a more accurate risk distribution by considering interrelationships among factors. The results offer dependable tools for spatial planning, early warning system development, and slope management in regions susceptible to landslides. Local authorities are advised to incorporate these findings into zoning regulations and prioritize conservation-oriented measures in areas of high susceptibility to improve long-term resilience.