Landslide activity and integrated monitoring network: the Greci slope (Lago, Calabrias, Italy)

A deep-seated gravitational slope deformation (DSGSD) and a number of landslides of different thickness and types affect the Greci slope (Lago, Calabria, Italy). The geological settlement of the area is characterized by the presence of tectono-metamorphic thrust sheet belonging to the Calabrian belt. The study concerns a moderately urbanized area, crossed by an important road, where the lithological-structural and hydrogeological conditions predispose to slope instabilities. This paper deals with the kinematic characteristics relative to the instability mechanisms in the Greci slope, defined with a long term monitoring. Specialized monitoring networks have been progressively realized since 1996 to measure the surficial and deep displacements (GPS benchmarks, GPS permanent stations and inclinometer verticals). After a period of continuous and intense rainfall (2008-2010), a detailed landslides inventory map has been prepared to update the landslides boundaries. The new elements and data acquired confirm that the mass movements mechanisms in the Greci slope are characterized by extremely slow or very slow rate of displacements (Cruden and Varnes classification). Moreover, new knowledge demonstrate the landslides may significantly accelerate and affect structures and infrastructures.