IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

1P2_3G-O23

Room A4

Date/Time: July 21 18:00-18:15

Numerical modeling of the Mount steller rock-ice avalanche flow history and it’sassociated seismic signal.
Laurent Moretti1 , Anne Mangeney1 , Yann Capdeville2 , Eleonore Stutzmann1 , Christian Huggel3 ,Demian Schneider3 , Francois Bouchut4
1

Institut de Physique du Globe de Paris, Equipe Sismologie, Paris., France, 2 Laboratoire dePlanétologie et Géodynamique de Nantes, Nantes., France, 3 University of Zurich, Department ofGeography. Glaciology, Geomorphodynamics and Geochronology., Switzerland, 4 LAMA-UMR 8050,
Université Paris-Est-Marne-la-Vallée, Marne la Vallée., France
E-mail: lmoretti@ipgp.fr

Gravitational instabilities, such as landslides, avalanches or debris flows play a key role in erosion processes andrepresent one of the major natural hazards in mountainous, coastal or volcanic regions. Despite the great amountof field, experimental and numerical work devoted to this problem, the understanding of the physical processes atwork in gravitational flow is still an open issue, in particular due to the lack of observations relevant to their dynamics.

In this context, the seismic signal generated by gravitational flows is a unique opportunity to get informationon their dynamics. Indeed, as shown recently by Favreau et al., (2010) and Moretti et al.(2012), simulation of
the seismic signal generated by landslides makes it possible to discriminate different flow scenarios and estimate
the rheological parameters during the flow. Because global and regional seismic networks continuously recordgravitational instabilities, this new method will help gathering new data on landslide behavior.

The purpose of our research is to establish new relationships making it possible to extract landslide characteristics
such as volume, mass, geometry and location, from seismic observations (amplitude,duration,energy...).

The Mount Steller rock-ice avalanche, that occurred the 14th Septmeber 2005 in the south of Alaska, andthe associated seismic waves have been simulated. We shown that the stress field applied on the ground surface
by the landslide is highly sensitive to the flow history, that is to say, sensitive to the rheological properties and thephysical processes, as erosion, involved in the flow.

Moretti, L., Mangeney, A., Capdeville, Y., Stutzmann, E., Christian Huggel, C., Schneider, D., and Francois
Bouchut, F., 2012. Numerical modeling of the Mount Steller landslide flow history and of the generated long period
seismic waves, Geophys. Res. Lett., 39, L16402

Favreau, P., Mangeney, A., Lucas, A., Crosta, G.B., and F. Bouchut, Numerical modeling of landquakes.
Geophysical Research Letters, VOL. 37, L15305, doi:10.1029/2010GL043512, 2010

Huggel, C., Caplan-Auerbach, J., Molnia, B. and Wessels R. (2008), The 2005 Mt. Steller, Alaska, rock-ice
avalanche: A large slope failure in cold permafrost, Proceedings of the Ninth International Conference on
Permafrost, vol. 1., p. 747-752, Univ. of Alaska Fairbanks©IAVCEI 2013 Scientific Assembly. All rights reserved.

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