Climate Change and Landslide Hazard in the Rif Mountains, Morocco: AComprehensive Geospatial and Geotechnical Evaluation

Abstract

Landslides are prevalent in the Rif Mountains of Northern Morocco due to their geological makeup and morphology. The area has a steep gradient and receives high amounts of precipitation. Humans are also hurting this region and increasing the potential of landslide hazards. This paper analyzes and assesses the landslide hazard in the Rif area; the main approach was to develop a landslide susceptibility model. The model was created by utilizing Geographic Information Systems (GIS) and incorporating nine factors that contribute to landslide occurrence: slope, aspect (i.e., the direction the steepest slope faces), type of bedrock, distance from fault lines, distance to roads, type of land use, amount of vegetation, amount of rainfall, and soil moisture content. A total of 127 landslides that have been documented have been investigated in the field. The analytical hierarchy process (AHP), combined with frequency ratio analysis, concluded that approximately 23% of the area has a high to very high landslide susceptibility and affects significant infrastructure and population centers in Chefchaouen, Al Hoceima, and Tetouan provinces. An area under the curve (AUC) value of 0.87 indicates that a very good predictive accuracy was obtained from the Receiver Operating Characteristic (ROC) curve analysis of the susceptibility model. Annual economic losses due to landslide events were estimated at over $45 million (in US currency) and will adversely affect the transportation network, agricultural production, and overall community resilience in the Rif Region. This study represents a scientific basis for developing land management strategies based on evidence for managing the risk of landslides in the Rif Region and provides an applicable methodological approach to manage risk in other mountainous areas throughout the Mediterranean Region.