LPC® methodology as a tool to create real time cartography of the gravitational hazard

Abstract

Landslides represent a serious risk in steep areas like mountainous landscapes. Emergency management planning requires prediction of the damage, associated to the landslide occurrence. This paper presents the recent advances in the LPC (Landslide Predictive Cartography) methodology. For each time laps, this deterministic modelling assesses the slope stability in relation with real or modelled climatic events. The objective of this study is to compare and validate this new methodology to a heuristic approach on the Isola catchment (Maritimes Alps, France). The study area is localised on the Argentera crystalline massif, in a valley showing paraglacial landforms. A field campaign was realised to assess the hydrogeological, physical and mechanical parameters for lithology formations that has been mapped. The LPC methodology has been found to be helpful in the management of landslide zones. One of the simulations examined in this paper, presents a 25 m DEM scale resolution, considering a 20-year return rainfall modelled (48.6 mm cumulated for a one hour rainfall event/occurrence). The results obtained indicate that 18.7% of the studied area might be unstable and that 58.6% of the landslides that have occurred have a Factor of Safety (FS) lower than 1.