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| Titel |
Long term monitoring at Solfatara of Pozzuoli (Campi Flegrei, Italy): 1998-2014, fifteen years of soil CO2 flux measurement. |
| VerfasserIn |
Carlo Cardellini, Giovanni Chiodini, Angelo Rosiello, Emanuela Bagnato, Rosario Avino, Francesco Frondini, Marco Donnini, Stefano Caliro |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107330
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| Publikation (Nr.) |
 EGU/EGU2015-7027.pdf |
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| Zusammenfassung |
| With a flux of deeply derived fluids of ~5000 t/d and an energetic release of ~100 MW
Solfatara of Pozzuoli is one of the largest studied volcanic-hydrothermal system of the
world. Since 1998, soil CO2 flux surveys where performed using the accumulation
chamber method over a large area (1.45 km2), including the volcanic apparatus
and its surroundings. The statistical elaboration of CO2 flux, also coupled with the
investigation of the CO2 efflux isotopic composition, allowed to characterize both
the CO2 flux connected to by biological activity in the soil and that feed to the
degassing of the hydrothermal system. A geostatistical elaboration of CO2 fluxes
based on sequential Gaussian simulations, allowed to define the spatial structure of
the degassing area, pointing out the presence of a well defined diffuse degassing
structure interested by the release of deeply derived CO2 (Solfatara DDS). Solfatara
DDS results well correlated to volcanic and tectonic structures interesting the crater
area and the eastern area of Pisciarelli. With the same approach the total amount
of CO2 release was estimated to range between 754 t/d and 1530 t/d in the last
fifteen year (with an error in the estimate varying between 9 and 15 %). Also the
extension of the DDS experienced relevant variations varying between 4.5x105 m2 to
12.3 x105 m2. In particular two major changes occurred in the extension of the
DDS, the first consisted in its doubling in 2003-2004 and the second in further
enlargement of ~ 30% in 2011-2012, the last occurring after period of decreasing trend
which interrupted 4-5 years of relative stability. These variations mainly occurred
external to the crater area in correspondence of a NE-SW fault system where fluxes
increased from background to values typical of the endogenous source. The first event
was previously correlated with the occurrence in 2000 of a relatively deep seismic
swarm, which was interpreted as the indicator of the opening of an easy-ascent
pathway for the transfer of magmatic fluids towards the shallower portion of the
hydrothermal system; the second event of DDS enlargement well correlates with the recent
unrest phase of the system, characterised by an acceleration of the ground uplift.
The comparison of the CO2 flux data with the chemical composition of the main
fumaroles suggests that the enlargements in the extension of the DDS are controlled by
processes of pressurization of the buried gas plume feeding the Solfatara manifestation. |
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