AbstractLandslides are well known processeses that hamper sustainable development efforts particularly in developing countries where extreme poverty is already a household to societal problem. Though a worldwide problem, landslides remains enigmatic especially with regards to their geometry, causative factors, triggering mechanisms, and the relationship between triggering factors, slide occurrence and the susceptibility of any area to mass wasting phenomena. This thesis presents an inventory and thorough analysis of small-scale devastating landslides that occurred in the city of Limbe at the base of Mt Cameroon and its environ in recent years.
A multidisciplinary approach was adopted in order to understand the complex and multi-phase nature of landslide processes. This involved integrating results of traditional field mapping, rainfall measurements, analyses of geotechnical properties of soils, soil mineralogy and soil geochemistry to get and idea of the processes and mechanism involved in landslide initiation and mobilisation. From these results, two conceptual models were proposed to explain the occurrence of landslides affecting vulnerable people. The thesis thus provides first hand field-measured geometric characteristics of landslide scars and systematically documents and quantifies for the first time the overall features, of volume-limited devastating slides in Limbe. Hence, it provides constraints for modelling, monitoring and remediation efforts that might be applied in other areas affected by similar small-scale failures.
Field observations, geotechnical and mineralogical characterisation suggest that slope failure within the study area is enhanced by human intervention through anarchical construction and slope undercutting. This implies that in the absence of external factors the slopes within the study area would generally remain stable for long periods. This study suggests that understanding of the triggering processes and the relationship between triggers and slide occurrence could be improved through more accurate recording of landslide timing and the corresponding triggering events. This knowlegde can be used in landslide susceptibility assessment which wwas one of the most significant achievements of this thesis, and in the development of early warning systems that might enable a reduction in the number of casualties and a certain amount of economic loss from future landslide phenomena.
The findings from the present study have generic value and can be used to tackle small-scale slope instability problems elsewhere in the subtropics.
|Date of Award||27 Jun 2011|
|Supervisor||Matthieu Kervyn De Meerendre (Co-promotor), Patric Jacobs (Promotor), Philippe Trefois (Co-promotor) & C. Emmanuel Suh (Co-promotor)|
- susceptbility assessment
- stability analysis
- Limbe, Cameroon
- geotechnical and mineralogical characterization