Comprehensive spatial analysis using frequency ratio and analytical hierarchy process approaches for landslide susceptibility assessment in Aceh Jaya, Indonesia

Abstract Landslides are recurrent disasters in Aceh Jaya Regency, driven by steep topography, intense rainfall, and the increasing rate of deforestation. These events frequently disrupt communities and damage critical infrastructure, causing economic losses and the displacement of residents. Therefore, precise landslide susceptibility mapping is crucial for effective disaster-risk mitigation. For this purpose, GIS-based Frequency Ratio (FR) and Analytic Hierarchy Process (AHP) approaches were applied to develop a rapid and operational landslide susceptibility map at the regional scale. The eight causative factors of landslides considered in this study were slope, lithology, lineament density, rainfall, drainage density, elevation, soil type, and land use/land cover (LULC). Causative factors were divided into sub-factors and weighted based on the FR and AHP approaches. The landslide susceptibility maps were categorized into five levels: very low, low, medium, high, and very high. The results show that the high to very high landslide susceptibility categories for FR and AHP were 40% (1,527 km 2 ) and 29% (1,090 km 2 ), respectively. Validation of the susceptibility map using receiver operating characteristic (ROC) method revealed an area under the curve (AUC) of 0.81 for the FR and 0.75 for the AHP models. Landslide density analysis further confirmed that that both approaches effectively discriminated landslide-prone areas, showing a clear spatial alignment between high-susceptibility classes and observed landslide concentrations. The findings of this study provide a first-order tool for landslide susceptibility assessment, offering critical guidance for planning and implementing targeted mitigation measures in the Aceh Jaya Regency.