Landslide Hazard Mapping

The Landslide Hazard Mapping theme (1989-1992) was the main objective of the GARS Latin America Project. A new methodology was developed in landslide hazard mapping that uses remote sensing data from optical and radar systems. These data were combined, a quantitative geomorphological study, with Geographic Information System (GIS) technology to generate maps of landslide susceptibility. These maps are used to minimize the risk of landslides and for land management.

Landslides are the main processes by which landscapes evolve and a widespread geological hazard. Landslides are driven by gravity and are characterized by movements of solid rock, debris or soil. These can be large and chaotic or small and subtle involving a wide variety of deformation and displacement. The landscape is forever changing and an assessment of landslide activity requires that the landscape be mapped and understood in detail.


Landslide hazard mapping was performed in Colobmia’s Chicamocha Valley, in the Andes Mountains, using field survey data, optical remote sensing data from Landsat TM and SPOT, and radar data from ERS and JERS satellites. A Digital Elevation Model (DEM) of the area was created using optical stereoscopic data to visually interpret the lithology, identify discontinuities and make land-use classifications. The stereo data were also used to digitise landslide boundaries and head scarps of debris flows. The DEM was used to conduct quantitative geomorphological mapping of the surface slope, exposures and drainage networks. The DEM was combined with a GIS to produce a 1:50,000 scale map of landslide susceptibility in the upper Chicamocha Valley.


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