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Continuous monitoring of hydrogen and carbon dioxide at Stromboli volcano
Author(s)
Valenza, M.
Dipartimento DiSTeM, Università di Palermo, Palermo, Italy
Type
Conference paper
Language
English
Obiettivo Specifico
5V. Sorveglianza vulcanica ed emergenze
1IT. Reti di monitoraggio e Osservazioni
Status
Published
Conference Name
EGU General Assembly
Issued date
April 2015
Conference Location
Vienna
Subjects
Abstract
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 secondabundant
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 (1016 – 108 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
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 secondabundant
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 (1016 – 108 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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