Rainfall induced landslide susceptibility mapping
Landslide risk maps at a regional scale.
The method (Nadim et al., 2006) is used to identify the global distribution of landslide hazards and risks. It uses existing global databases freely available online and classifies areas according to the hazard level. The elements exposed are overlapped with hazard maps in a GIS environment to build risk maps (i.e., hotspots). Quantification of the elements exposed is also made.
To identify the global landslide hazard and risk "hotspots," Nadim et al. (2006) adopted a simplified first-pass analysis method. The scale of the analysis is a grid of roughly 1km x 1km pixels where landslide hazard, defined as the annual probability of occurrence of a potentially destructive landslide event, is estimated by an appropriate combination of the triggering factors (mainly extreme precipitation) and susceptibility factors (slope, lithology, and soil moisture).
The weights of different triggering and susceptibility factors are calibrated to the information available in landslide inventories and physical processes (Figure 1).
Figure 1: Schematic approach for landslide hazard and risk evaluation (Nadim et al. 2006).
The landslide hazard indices were estimated using the following equations:
Hr = (Sr × S1 × Sv) × Tp
where
- Hr is the landslide hazard index for rainfall-induced landslides
- Sr is the slope factor within a selected grid
- Sl is lithological (or geological) conditions factor
- Sv is the vegetation cover factor Tp is the precipitation factor
Landslide hazard map Italy
Upcoming improvements/future services
The GIS-based tool can identify possible landslide-triggering areas. Combined use of the current method with simple runout analysis would help to identify risk areas and to quantify the population, structures, and infrastructures exposed.
The GIS tool will also implement a quantitative risk assessment with damage estimation.
WMS service with GAR data
WCS service with GAR data
GetCapabilities
URL to use in ArcGIS and QGIS desktop
References
- Farrokh Nadim, Christian Jaedicke, Helge Smebye, Bjørn Kalsnes (2006). Assessment of global landslide hazard hotspots. International Centre for Geohazards (ICG) / Norwegian Geotechnical Institute (NGI), Oslo, Norway. IPL Project C102
