Bulletin du Service Géologique de l'Algérie

Geoenvironmental Controls On Landslide Suscepti-bility In A Hilly Environment: A Comparative As-sessment Of Aïn Témouchent, Northwestern Algeria

Auteurs : Abbas Djamel Eddine . Mokhtar Karim . Bouhadad Youcef . Hadji Riheb . Hamed Younes . Arif Ismail . Gentilucci Matteo .

Résumé

Algeria is recurrently affected by natural hazards that can cause substantial human, economic, and environmental losses, posing persistent challenges to sustainable regional development. In northwestern Algeria, the wilaya of Aïn Témouchent is particularly exposed to multiple hazards, including landslides, floods, and earthquakes. Within this context, spatially explicit assessment of landslide susceptibility is essential for identifying unstable areas, supporting land-use planning, and strengthening proactive risk-reduction strategies. This study evaluates landslide susceptibility across Aïn Témouchent using two widely applied bivariate statistical approaches: the Frequency Ratio (FR) and Weight of Evidence (WoE) methods. The modelling framework combines a comprehensive landslide inventory with nine conditioning factors representing major topographic, geological, hydrological, climatic, and anthropogenic controls: slope, elevation, lithology, distance to drainage networks, distance to faults, distance to roads, aspect, rainfall, and land use. The resulting susceptibility maps were assessed using receiver operating characteristic (ROC) analysis to quantify their predictive capability. Both approaches showed satisfactory discrimination between landslide-prone and relatively stable areas, although WoE provided a modest but consistent improvement over FR, with AUC values of 0.79 and 0.75, respectively. The results indicate that incorporating the spatial relationships between documented landslides and their conditioning factors can effectively delineate areas with contrasting levels of susceptibility. Despite the moderate predictive performance, the WoE model offers a comparatively more reliable basis for regional-scale susceptibility assessment and can provide useful spatial support for prioritizing detailed investigations, land-use regulation, and landslide risk-reduction measures in Aïn Témouchent.

Mots clés

landslide ; susceptibility ; predisposing factors ; frequency ratio ; weight of evidence ; ROC