Assessing the spatial probability of landslides using GIS and informative value model in the Bamenda highlands
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ORIGINAL PAPER
Assessing the spatial probability of landslides using GIS and informative value model in the Bamenda highlands Roland Ngwatung Afungang 1 & Carlos Valdir de Meneses Bateira 2 & Clement Anguh Nkwemoh 3
Received: 17 June 2016 / Accepted: 8 August 2017 / Published online: 31 August 2017 # Saudi Society for Geosciences 2017
Abstract Landslides are a major natural hazard in the Bamenda highlands of Cameroon, and their occurrence in this region has most often been studied using qualitative methods. The aim of this research is to quantitatively assess the spatial probability of landslides using GIS and the informative value model. Landslide inventory was done through literature review, aerial photo-interpretation, participatory GIS and field survey. Six geo-environmental factors including slope, curvature, aspect, land use, lithology and geomorphology were used as landslide conditioning (static) factors. The susceptibility of the area to future landslide events was assessed by making a correlation between past landslides and geo-environmental factors using the informative value model. The landslide inventory involving 110 landslides was divided into two equal groups using random division criterion and was used to train and validate the model. The analysis showed that slope and land use are the most important causal factors of landslides in the area. The susceptibility index map predicted most landslides to occur around the steep slopes of the Bamenda escarpment that is being used for multiple
anthropic activities. The training model had a success rate of 87%, and the validation model had a prediction rate of 90%. The prediction rate curve shows that 44, 32, 18 and 6% of future landslides will occur on 3, 8, 21 and 68% of the study area. The model correctly classified 89% of unstable areas and 81% of the stable areas with an accuracy rate of 0.90. This quantitative result complement other qualitative assessment results that show the Bamenda escarpment zone as a highrisk area. However, the area susceptible to landslide in this study goes beyond what earlier studies had indicated as houses and other infrastructure were found on old landslide sites whose scars have been eroded by human activities. This new input thus improves the quality of information placed at the disposal of civil protection units and land use managers during decision making. Keywords Landslide susceptibility . Informative value . GIS . Predictive power . Bamenda, Cameroon
Introduction * Roland Ngwatung Afungang [email protected] Carlos Valdir de Meneses Bateira [email protected] Clement Anguh Nkwemoh [email protected] 1
Centre of African Studies, University of Porto (CEAUP), Via Panoramica, s/n, 4150-564 Porto, Portugal
2
Centro de Estudos de Geografia e Ordenamento do Território, University of Porto, Via Panoramica, s/n, 4150-564 Porto, Portugal
3
Department of Geography, University of Yaoundé 1, P O Box 755, Yaoundé, Cameroon
Landslide hazard is expressed as Bthe probability of occurrence within a specified period an
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