Preliminary analysis of landslide hazard in Brunei Darussalam, SE Asia

Abstract

Landslides are downslope movements of rock and soil materials under the influence of gravity, and often these are triggered by various causes, and the factors that govern the landslide occurrence in Brunei Darussalam, Borneo, have not been investigated in any detail, although landslide hazards are the second most damaging hazards in the country. The equatorial tropical monsoon conditions contribute to the cause of landslides in the sultanate, and our mapping of landslide sites in the Brunei-Muara region has revealed a number of key factors that initiate and influence the formation and nucleation of landslides. And these are mainly related to extent of urbanisation, amount and intensity of rainfall, loss of vegetation cover, slope and geological factors. These factors may or may not work together for a particular landslide event, but the occurrence of landslides has been linked to these factors. Gravitational active faults were also mapped at three landslide sites and related to creep. Google, and 30 m shuttle radar topography satellite images, followed by detailed fieldwork with the aid of unmanned aerial vehicle tool, were employed to map the topographic, structural, bedrock, and landslide details and to differentiate the types of landslides. The landslide and rainfall data were obtained from the National Disaster Management Centre and Geotechnical and Geological Section of the Public Works Department and used in combination with the bedrock and slope maps. Our work should be used by local administrative departments to plan any future anthropogenic activity in the region.