Documentation of Landslide Occurrence and Significance in Mbonjo, Limbe Town, South-West Cameroon

Abstract

Recent landslides in Mbonjo, located between 3°55 '' -4°13 '' N and 9°12 '' -9°23 '' E in the coastal town of Limbe were mapped using an unmanned aerial vehicle, field mapping and remote sensing techniques and documented in this paper. This town is susceptible to natural hazards and in July 2018 and 2020, a swarm of landslides occurred in Mbonjo towards the outskirt of Limbe, killing five people and injuring 10 others, obstructing the road and destroying important properties. These landslides were studied for a better understanding and the occurrence of such natural phenomena and human threat diminution. From the field studies, the slides were small to medium scale, characterized by low slope gradients (15-25 0 ), short depletion zones (20-25m) and length (~31.1m). These slides covered an area of 603.5-2000.75m 2 and the volume of ground debris were bracketed between 626.81 and 8757.60m 3 . Slope steepness and human activities such as excavation of the slopes were the main conditioning factors, whereas intense rainfall was the main trigger of Mbonjo landslides. It is urgent to take concrete measures to tackle this serious threat to human life in the study area.