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| Titel |
Diffuse CO2 flux emissions from the soil in Las Cañadas caldera (Tenerife, Canary Islands) |
| VerfasserIn |
Natividad Luengo-Oroz, Pedro A. Torres, David Moure, Walter D'Alessandro, Marco Liuzzo, Manfredi Longo, Giovannella Pecoraino |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094371
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| Publikation (Nr.) |
 EGU/EGU2014-9777.pdf |
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| Zusammenfassung |
| Starting in April 2004, unusual seismic activity was observed in the interior of
the island of Tenerife (Canary Islands, Spain) with much evidence pointing to a
reawakening of volcanic activity. During this seismic crisis, several events were felt
by the population. Since then, a dense multiparametric monitoring network has
been deployed all over the island by Instituto Geográfico Nacional (IGN). In the
framework of this volcanic surveillance project, several geochemical studies have been
accomplished.
Measurements of diffuse CO2 flux from the soil have been carried out in some zones
inside Las Cañadas caldera. This study has been performed during three different field
campaigns in November 2012 and June and November 2013.
The studied area includes two different zones known as Roques de García and Los
Azulejos. Since several authors have reported the existence of fractures and faults all along
both structures, the objectives of this work were to find anomalous CO2 fluxes
from the soil and preferential degassing areas, identify possible hidden faults and
study the origin of gas emanations in order to detect the presence of magmatic
sources.
More than 600 sampling sites have been measured with the accumulation chamber
method in an area of about 1 km2. Soil gas has been sampled in points where high CO2 fluxes
were detected for the determination of chemical and isotopic composition.
The results of the gas prospection confirm the existence of CO2 degassing in the area.
Some anomalous fluxes have been measured along previously inferred volcano-tectonic
structures. The highest anomalies were found in Los Azulejos with values up to 1774
g/m2.d.
Chemical analysis did not reveal significant concentrations of magmatic or geothermal
gases except CO2. The latter showed concentrations at 50 cm depth within the soils up to
48% and a C-isotopic composition between -4.72 and -3.67 oindicating a prevailing
magmatic origin. |
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