Quantitative Rockfall Hazard Assessment at the Mont Saint-Eynard (French Alps)

Estimation quantitative de l'aléa éboulement au Mont Saint-Eynard (Alpes françaises)

Didier Hantz (1) , Jean-Pierre Rossetti (1) , Damien Valette (1) , Franck Bourrier (2)

1 ISTerre - Institut des Sciences de la Terre
2 INRAE - Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement

A methodology is proposed for quantitative assessment of impact frequency on an element at risk located on a slope under a rock cliff, from the volumetric retreat rate of the cliff, the distribution of the block volumes and the simulation of the block trajectories. The volumetric retreat rate is derived from diachronic terrestrial laser scanning and integration of a power law distribution of the rockfall volume. The frequency and the size of the falling blocks are determined from the power law distribution of the block volume, which is derived from a survey of the blocks fallen on the slope. Finally, the impact frequency is obtained from the simulation of block falls occurring during a given period, using the computer program Rockyfor3D. The method is applied to the Mont Saint-Eynard cliff, which overhangs the Grenoble urban area.

Keywords: rockfall; hazard; cliff; retreat rate; block size distribution; impact frequency

Domains: Sciences of the Universe [physics]; Environmental Sciences

Didier Hantz, Jean-Pierre Rossetti, Damien Valette, Franck Bourrier. Quantitative Rockfall Hazard Assessment at the Mont Saint-Eynard (French Alps). 6th Interdisciplinary Workshop on Rockfall Protection, May 2017, Barcelona, Spain. ⟨insu-03598733⟩