HR: 1340h
AN: V53C-1416    [Abstracts]
TI: Exponential Acceleration of VT Seismicity in the Years Prior to Major Eruptions of Basaltic Volcanoes
AU: * Lengline, o
EM: olivier.lengline@univ-savoie.fr
AF: LGIT, Universite de Savoie, Le Bourget du Lac, 73376, France
AU: Marsan, D
EM: david.marsan@univ-savoie.fr
AF: LGIT, Universite de Savoie, Le Bourget du Lac, 73376, France
AU: Got, J
EM: jlgot@univ-savoie.fr
AF: LGIT, Universite de Savoie, Le Bourget du Lac, 73376, France
AU: Pinel, V
EM: virginie.pinel@univ-savoie.fr
AF: LGIT, Universite de Savoie, Le Bourget du Lac, 73376, France
AB: The evolution of the seismicity at three basaltic volcanoes (Kilauea, Mauna-Loa and Piton de la Fournaise) is analysed during phases of magma accumulation. We show that the VT seismicity during these time-periods is characterized by an exponential increase at long-time scale (years). Such an exponential acceleration can be explained by a model of seismicity forced by the replenishment of a magmatic reservoir. The increase in stress in the edifice caused by this replenishment is modeled. This stress history leads to a cumulative number of damage, ie VT earthquakes, following the same exponential increase as found for seismicity. A long-term seismicity precursor is thus detected at basaltic volcanoes. Although this precursory signal is not able to predict the onset times of futures eruptions (as no diverging point is present in the model), it may help mitigating volcanic hazards.
DE: 7280 Volcano seismology (8419)
DE: 8434 Magma migration and fragmentation
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting