The catastrophic geomorphological processes in humid tropical Africa: A case study of the recent landslide disasters in Cameroon

Abstract

A retrospective analysis of data from the last three decades, clearly indicates an upward trend in the number of landslides and mudflows in Cameroon. Their impact on human beings, environment and properties has increased considerably. For example, since June 2001, several cases have been recorded, among which two resulted in significant human losses: twenty three deaths in June 2001 in Limbe town, twenty five others in July 2003 at Magha and its surroundings in the Bamboutos Mountains. These last two events were really spectacular and may be sounding the alarm of a geomorphological crisis in the region. According to each case, several tens or hundreds of landslides of different types and magnitudes occurred within a few minutes or hours, extending over an area of several tens of square kilometres. The reasons for this catastrophic evolution in the geomorphological processes in Cameroon are natural and anthropogenic. Among others, the natural factors are the changing climatic conditions, with the occurrence of very exceptional rainfalls and the uneven topography of the affected zones, for example with very steep slopes, as in the Magha zone of which area about fifty percent is above twenty degrees. The anthropogenic factors are also very relevant, with the increasing human pressure on the environment, characterised by the extension and/or intensification of the agro-pastoral activities (in the rural areas) and the anarchical settlement on the sloping urban zones.