Mapping release and propagation areas of permafrost-related rock slope failures to identify hot spots for hazard assessment, French Alps

• Main Authors: Cathala, Maëva, Magnin, Florence, Ravanel, Ludovic, Dorren, Luuk, Zuanon, Nicolas, Berger, Frédéric, Bourrier, Franck, Deline, Philip
• Other Authors: Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG), Bern University of Applied Sciences (BFH), A2 Photonic Sensors (A2PS), Laboratoire des EcoSystèmes et des Sociétés en Montagne (UR LESSEM), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA), Modélisation, simulation et commande des systèmes dynamiques non lisses (TRIPOP), Centre Inria de l'Université Grenoble Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP), Université Grenoble Alpes (UGA)
• Format: Conference Object
• Language: English
• Published: CCSD 2023
• Subjects: [SDE]Environmental Sciences; [SDE.MCG]Environmental Sciences/Global Changes; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SHS.GEO]Humanities and Social Sciences/Geography; Mont Blanc; permafrost
• Online Access: https://hal.science/hal-04755871; https://doi.org/10.57757/IUGG23-1859

International audience Permafrost-affected rockwalls are increasingly impacted by the effects of climate change and rising air temperature leading to rock slope failures. These events could be a threat for human lives and infrastructure, which underlines the need of better knowledge about their triggering mechanism and propagation. The aim of this study was to propose a regional mapping approach of susceptible release areas of rock slope failures and resulting runout distances. This information is a first step to identify hotspots for subsequent hazard assessment. To do so, we used an inventory of 1389 rock slope failures (volume > 10 2 m 3 ) recorded in the Mont-Blanc massif on 2007-2019 period and determined the topographical and permafrost conditions that are most prone to their triggering using a digital terrain model and a permafrost map. These conditions are used in a multi-criteria GIS approach to identify potential unstable slopes at the French Alps scale. Then, the potential release area map is used as input to map the propagation of potential events, using a model based on a normalised area dependant energy line principle. The resulting maps of release and propagation areas will be used to point out human assets (mountaineering routes, high mountain infrastructure, tourism areas) and lakes (that can provoke cascading hazards) which could be impacted by rock slope failure hazards. This work is a first step to identify hot spots for a regional hazard assessment where more in depth analyses will be required to evaluate potential risks at a local scale.