Mapping landslide susceptibility for the Carribbean island of Tobago using GIS multi-criteria evaluation techniques with a varied weighted approach

A GIS based methodology for evaluating landslide susceptibility for the Caribbean island of Tobago using GIS, multi-criteria evaluation techniques with a varied weighted approach using Boolean overlay is presented. The degree of susceptibility was weighted based on the prevalence of the condition of aspect, geology and slope in terms of acreage. The outcomes are presented as low, medium, high and severe susceptibility of areas to landslides. The areas to the south and west of Tobago were of either low or medium susceptibility to landslides. The northeast facing slopes along the Main Ridge of Tobago were of severe susceptibility. The outcomes are compared to previous research using an even weighted approach on landslides. The largest difference occurred in the medium susceptibility range followed by the high, low and severe ranges. In both cases, the susceptibility increased from the southwest part of the island of Tobago towards the Main Ridge area and the north-eastern part of the island. The landslide susceptibility map produced is a valuable tool, providing a basis for conducting detailed site-specific investigation on areas with high and severe susceptibility to landslides, which already have or plan to have infrastructure development.