18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif
Abstract 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 catal...
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Online Access: | http://dx.doi.org/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d/pdf |
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crioppubl:10.1088/1748-9326/ad281d 2024-06-02T08:08:02+00:00 18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif Courtial-Manent, Léa Ravanel, Ludovic Mugnier, Jean-Louis Deline, Philip Lhosmot, Alexandre Rabatel, Antoine Duvillard, Pierre-Allain Batoux, Philippe 2024 http://dx.doi.org/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d/pdf unknown IOP Publishing http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining Environmental Research Letters volume 19, issue 3, page 034037 ISSN 1748-9326 journal-article 2024 crioppubl https://doi.org/10.1088/1748-9326/ad281d 2024-05-07T14:06:52Z Abstract 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 IOP Publishing Mont Blanc ENVELOPE(69.468,69.468,-49.461,-49.461) Ronde ENVELOPE(141.258,141.258,-66.793,-66.793) Environmental Research Letters 19 3 034037 |
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IOP Publishing |
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unknown |
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Abstract 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 |
Courtial-Manent, Léa Ravanel, Ludovic Mugnier, Jean-Louis Deline, Philip Lhosmot, Alexandre Rabatel, Antoine Duvillard, Pierre-Allain Batoux, Philippe |
spellingShingle |
Courtial-Manent, Léa Ravanel, Ludovic Mugnier, Jean-Louis Deline, Philip Lhosmot, Alexandre Rabatel, Antoine Duvillard, Pierre-Allain Batoux, Philippe 18-years of high-Alpine rock wall monitoring using terrestrial laser scanning at the Tour Ronde east face, Mont-Blanc massif |
author_facet |
Courtial-Manent, Léa Ravanel, Ludovic Mugnier, Jean-Louis Deline, Philip Lhosmot, Alexandre Rabatel, Antoine Duvillard, Pierre-Allain Batoux, Philippe |
author_sort |
Courtial-Manent, Léa |
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 |
http://dx.doi.org/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d https://iopscience.iop.org/article/10.1088/1748-9326/ad281d/pdf |
long_lat |
ENVELOPE(69.468,69.468,-49.461,-49.461) ENVELOPE(141.258,141.258,-66.793,-66.793) |
geographic |
Mont Blanc Ronde |
geographic_facet |
Mont Blanc Ronde |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_source |
Environmental Research Letters volume 19, issue 3, page 034037 ISSN 1748-9326 |
op_rights |
http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining |
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_ |
1800753194277535744 |