EGU23-8130, updated on 25 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The competing roles of seismicity and rainfall in slope destabilization: rockfalls triggered on a metastable volcanic edifice

Virginie Durand1, Anne Mangeney2, Pascal Bernard2, Xiaoping Jia3, Fabian Bonilla2,4, Claudio Satriano2, Jean-Marie Saurel2, El Madani Aissoui2, Aline Peltier2,5, Valérie Ferrazzini2,5, Philippe Kowalski2,5, Frédéric Lauret2,5, Christophe Brunet2,5, and Clément Hibert6
Virginie Durand et al.
  • 1Geoazur, SOPHIA ANTIPOLIS, France (
  • 2Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, F-75005, France
  • 3Institut Langevin, ESPCI Paris Tech, CNRS UMR 7587, Paris, France
  • 4Geotechnical Engineering, Environment, Natural Hazards and Earth Sciences Department, Université Gustave Eiffel, Marne-la-Vallée, 77447, France.
  • 5Observatoire Volcanologique du Piton de la Fournaise, Institut de Physique du Globe de Paris, La Plaine des Cafres, F-97418, La Réunion, France
  • 6Institut Terre Environnement de Strasbourg, ITES, CNRS UMR 7063, University of Strasbourg/EOST, Strasbourg, France

The quantification of the effects of external forcings such as seismicity and rainfall on slope destabilization is an open and important question. To investigate the role of these forcings, we analyze an unprecedented 10-year long catalog of the rockfalls occurring in the Piton de la Fournaise volcano crater. Indeed, the dense seismic network operated by the Piton de la Fournaise Volcano Observatory (La Réunion Island) makes it possible to precisely locate the rockfalls and recover the volume of each event. We use statistical tools originally developed for earthquakes to study the spatio-temporal evolution of the rockfall activity and to unravel the impact of the external forcings. Our results highlight the predominant effect of low amplitude seismicity on the slope destabilization, via a progressive damaging of the slopes. Moreover, we show that the efficiency and the time delay of this dynamic triggering depends on the stability state of the slopes, i.e. the distance to failure. To better understand our observations, we compare them with laboratory experiments on granular avalanches triggered by ultrasound.


How to cite: Durand, V., Mangeney, A., Bernard, P., Jia, X., Bonilla, F., Satriano, C., Saurel, J.-M., Aissoui, E. M., Peltier, A., Ferrazzini, V., Kowalski, P., Lauret, F., Brunet, C., and Hibert, C.: The competing roles of seismicity and rainfall in slope destabilization: rockfalls triggered on a metastable volcanic edifice, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8130,, 2023.