18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif
Since the end of the 20th century, each decade has been warmer than the previous one in the European Alps. As a consequence, Alpine rock walls are generally facing high rockfall activity, likely due to permafrost degradation. We use a unique terrestrial laser scanning derived rockfall catalog over 1...
Published in: | Environmental Research Letters |
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IOP Publishing
2024
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Online Access: | https://doi.org/10.1088/1748-9326/ad281d https://doaj.org/article/68524309f9aa48d7a39a7f7cec889b3e |
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ftdoajarticles:oai:doaj.org/article:68524309f9aa48d7a39a7f7cec889b3e 2024-09-15T18:11:36+00:00 18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif Léa Courtial-Manent Ludovic Ravanel Jean-Louis Mugnier Philip Deline Alexandre Lhosmot Antoine Rabatel Pierre-Allain Duvillard Philippe Batoux 2024-01-01T00:00:00Z https://doi.org/10.1088/1748-9326/ad281d https://doaj.org/article/68524309f9aa48d7a39a7f7cec889b3e EN eng IOP Publishing https://doi.org/10.1088/1748-9326/ad281d https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/ad281d 1748-9326 https://doaj.org/article/68524309f9aa48d7a39a7f7cec889b3e Environmental Research Letters, Vol 19, Iss 3, p 034037 (2024) rockfalls erosion rates permafrost degradation glacier retreat terrestrial laser scanning Mont-Blanc massif Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 article 2024 ftdoajarticles https://doi.org/10.1088/1748-9326/ad281d 2024-08-05T17:48:52Z Since the end of the 20th century, each decade has been warmer than the previous one in the European Alps. As a consequence, Alpine rock walls are generally facing high rockfall activity, likely due to permafrost degradation. We use a unique terrestrial laser scanning derived rockfall catalog over 18 years (2005–2022) compared with photographs (1859–2022) to quantify the evolution of the east face of Tour Ronde (3440–3792 m a.s.l.) in the Mont-Blanc massif (western European Alps) that is permafrost-affected. Overall, 210 rockfalls were identified, from 1 to 15 500 m ^3 . Forty-five events were >100 m ^3 while cumulated volume of events <10 m ^3 represents <1% of the fallen rocks. The rockfall magnitude-frequency distribution of the overall inventory follows a power law, with a mean exponent b of 0.44 ± 0.03, characterizing a high contribution of large rockfalls. The depth of failure ranges from a few centimeters to more than 20 m while 95% of the rockfalls depth is <5 m, highlighting the role of the active layer. The mean rock wall erosion rate is 18.3 ± 0.2 mm yr ^−1 for the 2005–2022 period and ranks in the top range of reported values in the Alps. It has greatly increased between the periods 2006–2014 and 2016–2022, probably in relation to a series of summer heat waves. The exceptional erosion rate of 2015 is driven by one large rockfall in August. Since 2006, an ice apron that covered 16 100 m ^2 has now almost vanished, and the surface of the glacier du Géant at the rock wall foot has lowered by several tens of meters. The retreat of these two ice masses contributed to the rock wall instability as more than 35% of the rockfall volume detached from the deglaciated surfaces. Article in Journal/Newspaper Ice permafrost Directory of Open Access Journals: DOAJ Articles Environmental Research Letters 19 3 034037 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
rockfalls erosion rates permafrost degradation glacier retreat terrestrial laser scanning Mont-Blanc massif Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
spellingShingle |
rockfalls erosion rates permafrost degradation glacier retreat terrestrial laser scanning Mont-Blanc massif Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 Léa Courtial-Manent Ludovic Ravanel Jean-Louis Mugnier Philip Deline Alexandre Lhosmot Antoine Rabatel Pierre-Allain Duvillard Philippe Batoux 18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
topic_facet |
rockfalls erosion rates permafrost degradation glacier retreat terrestrial laser scanning Mont-Blanc massif Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
description |
Since the end of the 20th century, each decade has been warmer than the previous one in the European Alps. As a consequence, Alpine rock walls are generally facing high rockfall activity, likely due to permafrost degradation. We use a unique terrestrial laser scanning derived rockfall catalog over 18 years (2005–2022) compared with photographs (1859–2022) to quantify the evolution of the east face of Tour Ronde (3440–3792 m a.s.l.) in the Mont-Blanc massif (western European Alps) that is permafrost-affected. Overall, 210 rockfalls were identified, from 1 to 15 500 m ^3 . Forty-five events were >100 m ^3 while cumulated volume of events <10 m ^3 represents <1% of the fallen rocks. The rockfall magnitude-frequency distribution of the overall inventory follows a power law, with a mean exponent b of 0.44 ± 0.03, characterizing a high contribution of large rockfalls. The depth of failure ranges from a few centimeters to more than 20 m while 95% of the rockfalls depth is <5 m, highlighting the role of the active layer. The mean rock wall erosion rate is 18.3 ± 0.2 mm yr ^−1 for the 2005–2022 period and ranks in the top range of reported values in the Alps. It has greatly increased between the periods 2006–2014 and 2016–2022, probably in relation to a series of summer heat waves. The exceptional erosion rate of 2015 is driven by one large rockfall in August. Since 2006, an ice apron that covered 16 100 m ^2 has now almost vanished, and the surface of the glacier du Géant at the rock wall foot has lowered by several tens of meters. The retreat of these two ice masses contributed to the rock wall instability as more than 35% of the rockfall volume detached from the deglaciated surfaces. |
format |
Article in Journal/Newspaper |
author |
Léa Courtial-Manent Ludovic Ravanel Jean-Louis Mugnier Philip Deline Alexandre Lhosmot Antoine Rabatel Pierre-Allain Duvillard Philippe Batoux |
author_facet |
Léa Courtial-Manent Ludovic Ravanel Jean-Louis Mugnier Philip Deline Alexandre Lhosmot Antoine Rabatel Pierre-Allain Duvillard Philippe Batoux |
author_sort |
Léa Courtial-Manent |
title |
18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
title_short |
18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
title_full |
18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
title_fullStr |
18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
title_full_unstemmed |
18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
title_sort |
18-years of high-alpine rock wall monitoring using terrestrial laser scanning at the tour ronde east face, mont-blanc massif |
publisher |
IOP Publishing |
publishDate |
2024 |
url |
https://doi.org/10.1088/1748-9326/ad281d https://doaj.org/article/68524309f9aa48d7a39a7f7cec889b3e |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_source |
Environmental Research Letters, Vol 19, Iss 3, p 034037 (2024) |
op_relation |
https://doi.org/10.1088/1748-9326/ad281d https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/ad281d 1748-9326 https://doaj.org/article/68524309f9aa48d7a39a7f7cec889b3e |
op_doi |
https://doi.org/10.1088/1748-9326/ad281d |
container_title |
Environmental Research Letters |
container_volume |
19 |
container_issue |
3 |
container_start_page |
034037 |
_version_ |
1810449193941073920 |