Landslide failure and runout susceptibility in the upper T. Ceno valley (Northern Apennines, Italy)

The 'Conditional Analysis' multivariate statistical method was used to evaluate Landslide Susceptibility (LS) in an area of the Italian Northern Apennines. An Inventory Landslide map, containing 518 landslides, and seven landslide-related factor maps (lithology, elevation, slope angle and aspect, profile and tangential curvatures, bedding/slope relations) were processed using a shell script that automatically carries out the whole procedure producing a final map with five Failure Susceptibility (FS) classes. The procedure was applied separately to the most frequent landslide typologies, namely, rotational slides, flows, and complex landslides, and for each of the 127 different combinations of the seven factors. To define areas potentially affected by the down-slope movement of the depleted material, four runout belts with different probabilities were distinguished around the classes with highest FS. By overlaying the resulting map with the map of the elements at risk, namely, settlements, roads, and streams, the spatial risk in the area was assessed.