[H-TT15] Geographic Information Systems and Cartography

[HTT15-04] Mass movement hazards and related risks analysis in Djoundé and vicinities (Far North Region, Cameroon)

Ghislain Zangmo Tefogoum¹, Amza Mfossi¹, *Takashi Oguchi², Merlin Gountié Dedzo³ (1.Départment of Earth Sciences, Faculty of Science, University of Maroua, Cameroon, 2.Center for Spatial Information Science, The University of Tokyo, 3.Department of Life and Earth Science, High Teacher Training College, University of Maroua, Cameroon)

Keywords:Rock and debris fall, Controlling factors, Vulnerabiity, Risk, Map, Djoundé

Cameroon has been experiencing several deadly mass movements for several decades. Djoundé and vicinities in Maroua (Far North) were selected for this work due to the frequent occurrence of such hazards. This work aims to study these hazards and their related risks to produce a hazard and risk map. Relevant field and lab work was undertaken. In the study area, the evidence of past hazards was inventoried, and the hazard's predisposing and triggering factors were analysed. Moreover, the vulnerability was categorised, and the population was interviewed to strengthen the data. This step allowed us to assess the risks related to the hazards. In the lab, controlling factors were analysed, and a hazard and risk map was developed. The generated hazard map shows that approximately 35%, 40% and 25% of the study area have high, medium and low probabilities of mass movement initiation, respectively. Blocks and debris fall, as well as debris flows, are the prominent threats to the vulnerability in and around Djoundé. The latter are of human, animal and material origins. The vulnerable humans include men (74), women (101) and children (665). Vulnerable animals are made up of cattle of beef (450), sheep (200), goats (350) and poultry (300). The material vulnerability encompasses houses, equipment, farms, cars, motorbikes, bicycles, etc. The assessment shows that rock and debris falls and flows will destroy 251 houses and eight plantation farms. In case of significant hazards, the estimated financial loss is about 3.1×10⁸ XAF (4.7×10⁵ Euros). Recommendations to reduce these risks include the sensitisation of the population in relation to mass movement hazards and the prohibition of construction on steep slopes.