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| Titel |
Monitoring the NW volcanic rift-zone of Tenerife, Canary Islands, Spain:
sixteen years of diffuse CO2 degassing surveys |
| VerfasserIn |
Fátima Rodriguez, Simon Halliwell, Damaris Butters, German Padilla, Eleazar Padrón, Pedro A. Hernández, Nemesio M. Pérez |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128462
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| Publikation (Nr.) |
 EGU/EGU2016-8451.pdf |
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| Zusammenfassung |
| Tenerife is the largest of the Canary Islands and, together with Gran Canaria, is the only one
that has developed a central volcanic complex characterized by the eruption of
differentiated magmas. At present, one of the most active volcanic structures in Tenerife is
the North-West Rift-Zone (NWRZ), which has hosted two historical eruptions:
Arenas Negras in 1706 and Chinyero in 1909. Since the year 2000, 47 soil CO2
efflux surveys have been undertaken at the NWRZ of Tenerife Island to evaluate
the temporal and spatial variations of CO2 efflux and their relationships with the
volcanic-seismic activity. We report herein the last results of diffuse CO2 efflux survey
at the NWRZ carried out in July 2015 to constrain the total CO2 output from the
studied area. Measurements were performed in accordance with the accumulation
chamber method. Spatial distribution maps were constructed following the sequential
Gaussian simulation (sGs) procedure. During 2015 survey, soil CO2 efflux values
ranged from non-detectable up to 103 g m−2 d−1. The total diffuse CO2 output
released to atmosphere was estimated at 403 ± 17 t d−1, values higher than the
background CO2 emission estimated on 143 t d−1. For all campaigns, soil CO2 efflux
values ranged from non-detectable up to 141 g m−2 d−1, with the highest values
measured in May 2005. Total CO2 output from the studied area ranged between 52
and 867 t d−1. Temporal variations in the total CO2 output showed a temporal
correlation with the onsets of seismic activity, supporting unrest of the volcanic
system, as is also suggested by anomalous seismic activity recorded in the area
during April 22-29, 2004. Spatial distribution of soil CO2 efflux values also showed
changes in magnitude and amplitude, with higher CO2 efflux values located along a
trending WNW-ESE area. Subsurface magma movement is proposed as a cause for the
observed changes in the total output of diffuse CO2 emission, as well as for the
spatial distribution of soil CO2 efflux. The increasing trend of total CO2 output
suggests increasing pressurization of the volcanic-hydrothermal system; a mechanism
capable of triggering dyke intrusion along the NWRZ of Tenerife in the near future. |
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