Cartographie en temps reel et système de pré-alerte pour les glissements de terrain dans les Alpes Suisses: La méthode OLPAC

摘要

Superficial and spontaneous landslides and mudslides are a common phenomenon in mountain areas. In the region of the Swiss Alps, they are mainly triggered by precipitations of high intensity or their succession in a short scale of time. This phenomenon isn't specific to the Alps but can be observed in all mountain areas around the world. With the augmentation of violent episode of precipitation due to global warming, spontaneous landslides are likely to become more and more regular, turning into earthflow, debris flow or mudflow. These processes could become very destructive for the population and their goods. Detection of landslides hazard potentialities in real-time is a major challenge in the years to come. The OLPAC (Operational Landslides Prevision and Alert Cartography) methodology, designed to respond to this problematic is here presented. It integrates the combination of two major components: a slope stability theory, a dynamic hydrogeological model. This deterministic methodology is the result of 23 years of researches and successive developments. This model is currently running on the region of the Val-d'Illiez (Valais, Suisse), which is regularly affected by spontaneous landslides and muldslides particularly during the May 2015 event. The detection effectiveness can be increased by setting a short time prediction of landslides hazard potentialities obtained thanks to predictive meteorological data.