Mapping release and propagation areas of permafrost-related rock slope failures in the French Alps: A new methodological approach at regional scale

Cathala, M.; Magnin, F.; Ravanel, L.; Dorren, Luuk; Zuanon, N.; Berger, F.; Bourrier, F.; Deline, P. (2024). Mapping release and propagation areas of permafrost-related rock slope failures in the French Alps: A new methodological approach at regional scale Geomorphology, 448, p. 109032. Elsevier 10.1016/j.geomorph.2023.109032

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Rock slope failure (RSF) from permafrost-affected rockwall is an emerging threat for human lives and infrastructure which raises a need for RSF hazard assessments in the alpine environment. This study proposes the first mapping approach to RSF release and propagation areas in the French Alps. By analysing a unique RSF database (1389 recent events in the Mont Blanc massif), we determine three levels of RSF Susceptibility Indexes (RSI) to map the potential release areas. We highlight a strong correlation between RSF and permafrost: 99 % of RSFs occurred from rockwalls with a Mean Annual Rock Surface Temperature (MARST) ≤ 3 °C and 35 % with MARST from −2 to 0 °C. The release area maps (34 km2 to 284 km2 depending on the RSI) are entered into a simple propagation model (RockavELA), using a dimensionless area-based energy line principle (i.e. reach susceptibility) to map propagation areas of potential RSFs. Three propagation limits are proposed, fitting the propagation characteristics of another RSF database containing 3497 events observed across the European Alps with heterogeneous propagation substrates, and merged with 48 additional events from high mountains in the French Alps. RockavELA reproduced the runout extent of 20 high mountain RSFs with <50 % of frontal and lateral error. Output maps show little sensitivity to the propagation limits (<25 % difference between the high and low propagation limits). This work is a preliminary step to identify potential hazard hot spots in the French Alps, and proposes a novel approach that could be applied in other mountain ranges.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Agricultural, Forest and Food Sciences HAFL School of Agricultural, Forest and Food Sciences HAFL > Multifunctional Forest Management > Mountain Forests, Natural Hazards and GIS
Name:	Cathala, M.; Magnin, F.; Ravanel, L.; Dorren, Luuk0000-0001-9344-9461; Zuanon, N.; Berger, F.; Bourrier, F. and Deline, P.
Subjects:	Q Science > QE Geology
ISSN:	0169555X
Publisher:	Elsevier
Funders:	[UNSPECIFIED] International ecorisQ association
Language:	English
Submitter:	Luuk Dorren
Date Deposited:	31 Jan 2024 11:14
Last Modified:	31 Jan 2024 11:14
Publisher DOI:	10.1016/j.geomorph.2023.109032
Uncontrolled Keywords:	Rock slope failure Permafrost hazard GIS Regional mapping Runout modelling
ARBOR DOI:	10.24451/arbor.21036
URI:	https://arbor.bfh.ch/id/eprint/21036