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Statistical analysis of the volcano seismicity during the 2007 crisis
Author(s)
Language
English
Obiettivo Specifico
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/116 (2011)
Publisher
AGU
Pages (printed)
B09312
Issued date
2011
Keywords
Abstract
We analyze the volcano seismicity recorded during the pre‐ and co‐eruptive regimes
of the 2007 effusive crisis at Stromboli volcano (Italy). Data‐set is composed of the
continuous recordings of a three‐component broad‐band seismometer and of a Sacks‐
Evertson strainmeter. Starting from the characterization of the non effusive phase as a
stationary state of equilibrium, we investigate the effusive phase as a non‐equilibrium
state. A statistical analysis reveals that the explosion occurrence is always driven by a
nearly Poissonian process, as for the standard activity, even during the effusive phase, with
the only difference in shortening the inter‐times. Explosion‐quake amplitudes are
lognormally distributed until the effusive phase, becoming then broader. This indicates that
many scales are involved. A slightly different process can be advocated for the swarms of
the explosions occurring during the effusive phase. This suggests that the dynamics of the
exsolution and/or aggregation of the gas slugs should differ from the nucleation
mechanism responsible of the standard Strombolian activity. The pre‐eruptive regime is
characterized by a very long deformative signal that appears as a transient oscillating
signal with a period of about three days that modulates the explosion amplitudes. In a
conceptual vibrating cavities model, it is related to a chocking phenomenon induced by
magma injection, which in turn leads to the effusion.
of the 2007 effusive crisis at Stromboli volcano (Italy). Data‐set is composed of the
continuous recordings of a three‐component broad‐band seismometer and of a Sacks‐
Evertson strainmeter. Starting from the characterization of the non effusive phase as a
stationary state of equilibrium, we investigate the effusive phase as a non‐equilibrium
state. A statistical analysis reveals that the explosion occurrence is always driven by a
nearly Poissonian process, as for the standard activity, even during the effusive phase, with
the only difference in shortening the inter‐times. Explosion‐quake amplitudes are
lognormally distributed until the effusive phase, becoming then broader. This indicates that
many scales are involved. A slightly different process can be advocated for the swarms of
the explosions occurring during the effusive phase. This suggests that the dynamics of the
exsolution and/or aggregation of the gas slugs should differ from the nucleation
mechanism responsible of the standard Strombolian activity. The pre‐eruptive regime is
characterized by a very long deformative signal that appears as a transient oscillating
signal with a period of about three days that modulates the explosion amplitudes. In a
conceptual vibrating cavities model, it is related to a chocking phenomenon induced by
magma injection, which in turn leads to the effusion.
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article
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