Factors affecting mass movement hazards in and around Djoundé (FarNorth Region, Cameroon)

Abstract

Djoundé and its surroundings in Maroua, Cameroon, have been subjected to natural hazards in recent decades. This work aims at studying and mapping the factors of mass movement hazards in the study area to produce a hazard map. To achieve this, various field and indoor works have been carried out. The field studies facilitated the collection of data and information regarding the history of mass movements and the identification of mass movement hazard types. It also supported the analysis of factors controlling the hazards. The indoor work led to mapping factors and producing a mass movement hazard map for the study area. The inventory reveals that the most frequent mass movements are falls of rock blocks and debris, as well as debris flows. These phenomena are induced by natural and anthropogenic factors, predisposing and triggering. These factors are empirically ranked according to their importance in causing the hazards. Predisposing factors include inselbergs with basaltic and trachytic boulders, cracks and fissures on rocks, steep slopes (>65 % in places), vegetation cover dominated by grassland and sporadic trees, rainfall (747.69 mm/year), temperature (33.9 °C in April) and livestock farming. Triggering factors include the opening of quarries and summer rainfall (237.71 mm in August). From the generated hazards map, it can be deduced that approximately 35 %, 40 % and 25 % of the study area have high, medium and low probabilities of mass movement initiation, respectively. The low probability areas are often subject to gully erosion, not mass movements. This study contributes to understanding factors controlling the mass movement hazards in northern Cameroon. In addition, results from this study are helpful for the local authorities in implementing sustainable management policies.