Physico-chemical, mineralogical and chemical considerations in understanding the 2001 Mabeta New Layout landslide, Cameroon

Abstract

Landslides are part of natural catastrophic disasters destroying both biological and physical entities including loss of human lives. An evaluation of soil properties involved in landslides is significant in its management. To this effect, soil samples from the 2001 landslide occurrences in the Mabeta New Layout, Limbe, Cameroon were analysed using standard techniques to determine texture, pH, electrical conductivity (EC), bulk density (D b), water absorption percent (WA), linear shrinkage, plasticity index (PI), loss-on-ignition (LOI), mineral content and major cations. Results obtained were: bulk density (0.89-1.08 g/cm 3), LOI (19.4-25.7%), water absorption (23.4-29.1%), linear shrinkage (5.4-8.3%), volume shrinkage (4.8-8.5%), PI (13.5-20.75%), major cations ((Fe 2 O 3 : 9.91-23.24%), (Al 2 O 3 : 9.88-28.48%), (CaO : 0.73-1.3%), (MgO : 0.55-2.80%), (K 2 O : 1.06-1.59%), (Na 2 O : 0.77-0.89%)), pH (5.17-6.90) and EC (16.53-149.20µS/cm). Values from physico-chemical analyses, secondary minerals abundance index (SMAI) and chemical index of alteration (CIA) of the soils were reflective of particles with high potential for sliding. With major contributions from favourable slope, seismic and hydrologic forces, the event occurred. @JASEM Fig 1: Map of the study area showing its geology, hydrology and location of landslide scars, and geological cross-section (adopted from Ekosse et. al., 2005)