Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020)
International audience Abstract Although numerous recent studies have explored the relationship between permafrost degradation and rock slope failure, there is still a need for in‐depth investigations to develop relevant hazard assessment approaches. We investigate the predisposing, triggering and p...
Published in: | Earth Surface Processes and Landforms |
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Online Access: | https://hal.science/hal-04599885 https://doi.org/10.1002/esp.5881 |
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ftunigrenoble:oai:HAL:hal-04599885v1 2024-09-15T18:11:28+00:00 Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) Cathala, Maëva Bock, Josué Magnin, Florence Ravanel, Ludovic Ben Asher, Matan Astrade, Laurent Bodin, Xavier Chambon, Guillaume Deline, Philip Faug, Thierry Genuite, Kim Jaillet, Stéphane Josnin, Jean‐yves Revil, André Richard, Jessy Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) 2024-05-16 https://hal.science/hal-04599885 https://doi.org/10.1002/esp.5881 en eng HAL CCSD Wiley info:eu-repo/semantics/altIdentifier/doi/10.1002/esp.5881 hal-04599885 https://hal.science/hal-04599885 doi:10.1002/esp.5881 ISSN: 0197-9337 EISSN: 1096-9837 Earth Surface Processes and Landforms https://hal.science/hal-04599885 Earth Surface Processes and Landforms, 2024, ⟨10.1002/esp.5881⟩ [SDE]Environmental Sciences [SPI]Engineering Sciences [physics] info:eu-repo/semantics/article Journal articles 2024 ftunigrenoble https://doi.org/10.1002/esp.5881 2024-09-03T00:08:21Z International audience Abstract Although numerous recent studies have explored the relationship between permafrost degradation and rock slope failure, there is still a need for in‐depth investigations to develop relevant hazard assessment approaches. We investigate the predisposing, triggering and propagation processes of a rock avalanche (c. 225,000 m 3 ) that occurred in Vallon d'Étache (France) on 18 June 2020, whose scar was coated by ice and water. Weather records and energy balance models show that the rock avalanche occurred right after the warmest spring and winter since at least 1985, but also right after the spring with the highest water supply anomaly (snowmelt and rainfall). Measured ground surface temperature and geoelectrical surveys reveal that relatively ice‐rich permafrost could exist in the NW face (release area) while it is inexistent below the SE face, contradicting certain permafrost maps. Heat transfer simulations suggest that the rock avalanche occurred during a transition from cold to warm permafrost conditions at failure depth (30 m), with a temperature increase of up to 0.6°C per decade since 2012 (when considering potential snow cover effect), and current temperature ranging between −3 and −1°C, depending on the applied model forcing. This warming certainly contributed to predispose slope to failure. In addition, the shift towards warm permafrost and water infiltration potentially enhancing permafrost degradation along fractures through heat advection or favouring the development of high hydrostatic pressures may have played as triggering factors. Finally, propagation simulations show that the rock avalanche involved several phases with different rheological properties due to the incorporation of snow and material segregation within the deposit. These new insights at various scales highlight the complexity of the triggering and propagation processes of rock slope failure occurring in high mountains, a significant part of which can be linked to snow effects on ground temperature, ... Article in Journal/Newspaper Ice permafrost Université Grenoble Alpes: HAL Earth Surface Processes and Landforms 49 10 3221 3247 |
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Open Polar |
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Université Grenoble Alpes: HAL |
op_collection_id |
ftunigrenoble |
language |
English |
topic |
[SDE]Environmental Sciences [SPI]Engineering Sciences [physics] |
spellingShingle |
[SDE]Environmental Sciences [SPI]Engineering Sciences [physics] Cathala, Maëva Bock, Josué Magnin, Florence Ravanel, Ludovic Ben Asher, Matan Astrade, Laurent Bodin, Xavier Chambon, Guillaume Deline, Philip Faug, Thierry Genuite, Kim Jaillet, Stéphane Josnin, Jean‐yves Revil, André Richard, Jessy Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
topic_facet |
[SDE]Environmental Sciences [SPI]Engineering Sciences [physics] |
description |
International audience Abstract Although numerous recent studies have explored the relationship between permafrost degradation and rock slope failure, there is still a need for in‐depth investigations to develop relevant hazard assessment approaches. We investigate the predisposing, triggering and propagation processes of a rock avalanche (c. 225,000 m 3 ) that occurred in Vallon d'Étache (France) on 18 June 2020, whose scar was coated by ice and water. Weather records and energy balance models show that the rock avalanche occurred right after the warmest spring and winter since at least 1985, but also right after the spring with the highest water supply anomaly (snowmelt and rainfall). Measured ground surface temperature and geoelectrical surveys reveal that relatively ice‐rich permafrost could exist in the NW face (release area) while it is inexistent below the SE face, contradicting certain permafrost maps. Heat transfer simulations suggest that the rock avalanche occurred during a transition from cold to warm permafrost conditions at failure depth (30 m), with a temperature increase of up to 0.6°C per decade since 2012 (when considering potential snow cover effect), and current temperature ranging between −3 and −1°C, depending on the applied model forcing. This warming certainly contributed to predispose slope to failure. In addition, the shift towards warm permafrost and water infiltration potentially enhancing permafrost degradation along fractures through heat advection or favouring the development of high hydrostatic pressures may have played as triggering factors. Finally, propagation simulations show that the rock avalanche involved several phases with different rheological properties due to the incorporation of snow and material segregation within the deposit. These new insights at various scales highlight the complexity of the triggering and propagation processes of rock slope failure occurring in high mountains, a significant part of which can be linked to snow effects on ground temperature, ... |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) |
format |
Article in Journal/Newspaper |
author |
Cathala, Maëva Bock, Josué Magnin, Florence Ravanel, Ludovic Ben Asher, Matan Astrade, Laurent Bodin, Xavier Chambon, Guillaume Deline, Philip Faug, Thierry Genuite, Kim Jaillet, Stéphane Josnin, Jean‐yves Revil, André Richard, Jessy |
author_facet |
Cathala, Maëva Bock, Josué Magnin, Florence Ravanel, Ludovic Ben Asher, Matan Astrade, Laurent Bodin, Xavier Chambon, Guillaume Deline, Philip Faug, Thierry Genuite, Kim Jaillet, Stéphane Josnin, Jean‐yves Revil, André Richard, Jessy |
author_sort |
Cathala, Maëva |
title |
Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
title_short |
Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
title_full |
Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
title_fullStr |
Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
title_full_unstemmed |
Predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the French Alps (Étache, June 2020) |
title_sort |
predisposing, triggering and runout processes at a permafrost‐affected rock avalanche site in the french alps (étache, june 2020) |
publisher |
HAL CCSD |
publishDate |
2024 |
url |
https://hal.science/hal-04599885 https://doi.org/10.1002/esp.5881 |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_source |
ISSN: 0197-9337 EISSN: 1096-9837 Earth Surface Processes and Landforms https://hal.science/hal-04599885 Earth Surface Processes and Landforms, 2024, ⟨10.1002/esp.5881⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1002/esp.5881 hal-04599885 https://hal.science/hal-04599885 doi:10.1002/esp.5881 |
op_doi |
https://doi.org/10.1002/esp.5881 |
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Earth Surface Processes and Landforms |
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49 |
container_issue |
10 |
container_start_page |
3221 |
op_container_end_page |
3247 |
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1810449071591129088 |