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| Titel |
Continuous monitoring of hydrogen and carbon dioxide at Stromboli volcano |
| VerfasserIn |
Roberto M. R. Di Martino, Marco Camarda, Sergio Gurrieri, Mariano Valenza |
| 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 |
250112315
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| Publikation (Nr.) |
 EGU/EGU2015-12464.pdf |
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| Zusammenfassung |
| Geochemical monitoring of fumarole and soil gases is a powerful tool for volcano
surveillance, for investigating the subsurface magma dynamics, and for hazard assessment in
volcanic areas. The monitoring of both carbon dioxide (CO2) flux, and hydrogen (H2)
concentration in active volcanic areas helps to improve the understanding of the processes
linking the surface gas emissions, the chemistry of the magmatic gases, and the volcanic
activity.
The CO2 flux measurement is a routine technique for volcano monitoring purposes,
because of CO2 is the second-abundant component of the gas phase in silicate magmas,
attaining saturation at the mantle to deep crustal level. The H2 concentration has provided
indications concerning the oxygen fugacity of magmatic gases, a parameter that changes over
a wide range of low values (10-16 – 10-8 bar), and affects the redox state of multivalent
elements.
This study reports on the use a tailor-made automatic system developed for continuous
monitoring purposes of H2 concentration and CO2 flux in the summit area of Stromboli
volcano (Aeolian islands). The automatic device consists of an H2-selective electrochemical
sensor, and two IR-spectrophotometers for measuring the CO2 flux in agreement with the
dynamic concentration method.
The data collected by the automatic system deployed at Stromboli from 19 May 2009 to
15 December 2010 are presented herein. The data processing provides a better understanding
of the relationships between the evolution of the low temperature fumarolic emissions, and
the volcanic activity. The results of the data analysis indicates that the high frequency
variations exhibited by CO2 flux and H2 concentration are positively correlated with the
eruptive activity of Stromboli, typically changing on time scale of hours or days.
Furthermore, the investigation of the relationships between CO2 flux and H2 concentration
provides an evaluation of the depth of the degassing source, by which the gas mixture
containing H2 and CO2 starts to move through the rock fractures. Our data indicates
that the depth of the degassing source ranges between 2 and 4 km in the volcano
plumbing system, in agreement with the magma storage zone that has been proposed by
other geochemical, volcanological, petrological and geophysical investigations. |
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