HR: 11:35h
AN: V52B-06    [Abstracts]
TI: Toward Forecasting Volcanic Eruptions Using Seismic Noise
AU: * brenguier, f
EM: fbrengui@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, cedex 05, Paris, 75252, France
AU: Shapiro, N
EM: nshapiro@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, cedex 05, Paris, 75252, France
AU: Campillo, M
EM: michel.campillo@ujf-grenoble.fr
AF: Laboratoire de Géophysique Interne et Tectonophysique, BP53, Cedex 9, Grenoble, 38041, France
AU: Ferrazzini, V
EM: ferraz@ipgp.jussieu.fr
AF: Observatoire Volcanologique du Piton de la Fournaise - IPGP, 14 RN3, Km 27, La Plaine des Cafres, 97418, Reunion
AU: Duputel, Z
EM: zacharie.duputel@gmail.com
AF: Observatoire Volcanologique du Piton de la Fournaise - IPGP, 14 RN3, Km 27, La Plaine des Cafres, 97418, Reunion
AU: Coutant, O
EM: olivier.coutant@ujf-grenoble.fr
AF: Laboratoire de Géophysique Interne et Tectonophysique, BP53, Cedex 9, Grenoble, 38041, France
AU: Nercessian, A
EM: aln@ccr.jussieu.fr
AF: Institut de Physique du Globe de Paris, 4 place Jussieu, cedex 05, Paris, 75252, France
AB: Volcanic eruptions are preceded by the pressurization of magma leading to dilatations of volcanic edifices. Monitoring this process in real-time can provide us with a useful information to forecast volcanic eruptions. Volcano inflation generates ground deformations that can be revealed by spaceborne radar interferometry or by strain and tiltmeters. In some cases, however, volcano dilatation can be localized at depth with no measurable effects at the surface and it has proved difficult to monitor changes in volcanic interiors, despite considerable effort. Here we present an observation of a new type of precursory phenomena by demonstrating that pre-eruptive dilatations of the Piton de la Fournaise volcano can be detected as decreases of seismic velocity a few weeks prior to eruptions. We are able to monitor the changes of the volcano interior continuously in time and space by measuring very small relative seismic velocity perturbations (0.05%) by using the reproducibility properties of the ambient seismic noise. This new direct observation of the dilatation of volcanic edifices should improve our ability to forecast eruptions and to a priori assess their intensity (injected magma volume and flux) and environmental impact.
DE: 7280 Volcano seismology (8419)
DE: 8419 Volcano monitoring (7280)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting