HR: 11:50h
AN: V52B-07    [Abstracts]
TI: Hidden Dykes detected on Ultra Long Period seismic signals at Piton de la Fournaise volcano ? Constraints on the upper reservoir pressure state since 1992.
AU: Komorowski, J
EM: komorow@ipgp.jussieu.fr
AF: Géologie des Systèmes Volcaniques, IPGP, 4, Place Jussieu., Paris 05, 75252, France
AU: * Houlié, N
EM: houlie@seismo.berkeley.edu
AF: Berkeley Seismological Laboratory, 215, Mc Cone Hall - University of California, Berkeley, CA 94720, United States
AU: Montagner, J
EM: jpm@ipgp.jussieu.fr
AF: Département de Sismologie, IPGP, 4, Place Jussieu., Paris cedex 05, 75252, France
AU: Dufek, J
EM: dufek@berkeley.edu
AF: Earth and Planetary Science, 115, Mc Cone Hall - University of California, Berkeley, 94720, United States
AB: Broadband seismic data enable us to test whether Ultra Long Period (ULP) signals can be used to determine the magma chamber pressure state and to forecast volcanic eruptions. In a systematic investigation of seismic signals recorded at the GEOSCOPE station RER in la Réunion Island near the Piton de la Fournaise, we show that ULP signals from the past two decades are typically associated with eruptions of Piton de la Fournaise. Some of these unusual signals were previously detected and interpreted in terms of tilt (Battaglia et al., 2000). We tentatively propose to interpret these signals as signatures of the activity of the upper magma feeding system of the Piton de la Fournaise volcano chamber. They are detected using STS-1 seismometers sensitive in the lower part of the bandwidth 10^-3 to 10^-2 Hz. Assuming geometrical parameters of the source and magma injection rates in the upper reservoir, the collection of all seismic events allowed us to build a time-series of absolute pressure in the upper magma chamber. The absolute pressure framework provides new constraints to parametrize a wide range of geophysical and geochemical models together. This alternative model should provide new insights in the eruptive processes that characterize Piton de la Fournaise volcano (La Réunion).
DE: 8400 VOLCANOLOGY
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8419 Volcano monitoring (7280)
DE: 8425 Effusive volcanism
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting