Landslide Inventory of the Cinque Terre National Park, Italy

Landslide inventory maps are effective and easily understandable products both for experts, such as engineering geologists, and for nonexperts, including decision-makers, planners, and civil protection managers. At present, the Cinque Terre landscape suffers from the massive abandonment of cultivations on the terraces, with negative consequences for slope stability due to the increasing erosional processes. Each landform was digitized as a polygon using a GIS platform. Landslide detection was performed by a two-step method. The first step consisted of mapping landslides using orthophotos provided by Liguria Region, together with Google Earth imagery; the second step was a field verification study carried out between September and November 2015. Four hundred and five landslides were then identified and grouped into seven main typologies: a percentage distribution analysis of the different landslide types detected in Cinque Terre was then performed. A large number of debris slides (33.3%) indicates the vulnerability of dry-stone walls after large amounts of rainfall. Rockfalls (18.5%) are also frequent and especially concentrated along the eastern sector of the coastline. In addition, debris flows (12.6%) are widely distributed, especially along the western sector of Cinque Terre, among the Monterosso and Vernazza municipalities; these landslides were mainly triggered by the October 25th, 2011, meteorological event (382 mm of rainfall in 24 h recorded by the Monterosso al Mare weather station). Many landslides with complex evolutions (7% of the total) were detected along the coastline between Vernazza and Manarola; these events are historically well-known and extensively described in the literature.