HR: 0800h
AN: U21B-0819    [Abstracts]
TI: Measuring and Modeling Rock Deformation in the Vicinity of an Artificial Lake
AU: * Provost, A
EM: provost@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, Laboratoire de geomagnetisme, BP89, 4 place Jussieu, Paris cedex 05, 75252 France
AU: Perrier, F
EM: perrier@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, Laboratoire de geomagnetisme, BP89, 4 place Jussieu, Paris cedex 05, 75252 France
AU: Perrier, F
EM: perrier@ipgp.jussieu.fr
AF: Commissariat a l'energie atomique, BP 12, Bruyeres-le-Chatel, 91680 France
AU: Richon, P
EM: patrick.richon@cea.fr
AF: Commissariat a l'energie atomique, BP 12, Bruyeres-le-Chatel, 91680 France
AU: Pili, E
EM: eric.pili@cea.fr
AF: Commissariat a l'energie atomique, BP 12, Bruyeres-le-Chatel, 91680 France
AB: Important problems in earth sciences concern the deformation of the crust. Such a deformation is quantifiable through the observations of geophysical and hydrogeological phenomena that are associated to it. Determining the link between these phenomena and their driving forces is of great importance and can improve our understanding of geological and geophysical processes. These observations can be made via laboratory experiments, but it might not be ideal to understand crustal-scale phenomena. The Roselend experiment, set in the French Alps near an artificial lake, provides a field-scale setting for a multidisciplinary research project to study transfer processes and transient phenomena within a highly dynamic system (Provost et al., EOS Vol 85 No 12, 2004). In this setting the water level variations in the lake are acting as a natural press on the surrounding massif. The possibility to systematically measure and record variations of tilt in a neighboring tunnel, as well as water level in nearby boreholes, offers an unique opportunity to study the deformation induced by this natural press, and its implication in terms of geological phenomena. To monitor the deformation we are using long period seismometers, recording since October 2002, and we recently added a geodetic platform tiltmeter from Applied Geomechanics Inc. and Blum-Type pendulum tiltmeters in Silica. A time-series analysis of the observations shows a correlation between the relative tilt and the water level in the lake. Other transient phenomena, such as Radon bursts occur periodically and seem to correlate with an increase of the reservoir load after a low water-level period. In order to quantify the deformation induced by such water-level variations on it's surroundings, a finite element model was built. The preliminary results show a tilt variation of the same order as the one measured in the tunnel.
DE: 0545 Modeling (4255)
DE: 1822 Geomechanics
DE: 1857 Reservoirs (surface)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Union [U]
MN: Fall Meeting 2005