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| Titel |
The summit part of Mount Etna revealed by High Resolution DC Electrical Resistivity Tomography coupled with complementary geophysical and soil gas techniques |
| VerfasserIn |
Anthony Finizola, Tullio Ricci, Raphaël Antoine, Eric Delcher, Aline Peltier, Julien Bernard, Elodie Brothelande, Yannick Fargier, Cyrille Fauchard, Brice Foucart, Lydie Gailler, Rachel Gusset, Ivonne Lazarte, Martin Erwan, Cécile Mezon, Angélie Portal, Matthieu Poret, Matteo Rossi |
| 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 |
250132454
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| Publikation (Nr.) |
 EGU/EGU2016-12963.pdf |
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| Zusammenfassung |
| In the framework of the EC FP7 project “MEDiterranean SUpersite Volcanoes”, one profile coupling DC electrical resistivity tomography (Pole-Dipole configuration with a remote electrode located between 8-10 km from the middle of the different acquisitions, 64 electrodes and 40 m spacing between the electrodes), self-potential, soil CO2 degassing, Radon measurements and sub-surface (30cm depth) temperature have been performed between June 25th and July 13th 2015.
This profile, NE-SW direction, crossed the summit part of Mount Etna. A total 5720m of profile was performed, with a roll along protocol of 1/4 of the dispositive, for each new acquisitions. A total of 6 acquisitions was made to complete the entire profile.
For the first time in the world, a multi-electrodes DC ERT profile, of high resolution (40 m of spacing between the electrodes) reached, thanks to a pole-dipole configuration, 900m for the depth of investigation.
The ERT profile clearly evidences the hydrothermal system of Mount Etna: the lowest resistivity values are associated with a large scale positive self-potential anomaly, and smaller wavelength anomalies for temperature, CO2 concentration and Radon, in the area where the electrical conductor reach the surface.
Structural discontinuities such as the Elliptic crater, was clearly evidenced by a sharp decrease of the self-potential values in the inner part of this crater.
The striking result of this profile is the presence of a resistive body located just below the NE crater. This structure displays the highest degassing values of the entire profile. We interpret this resistive body as a consequence of the thermic over-heated plume rising from the top of the shallow feeding system. Indeed, above several hundred of degrees Celsuis, it is impossible to consider rain water infiltration and the presence of a wet hydrothermal system. The consequence would be therefore to obtain this resistive body, centred on the area of main heat transfer.
Above this resistive body, we clearly note a preferential hydrothermal fluid flow, associated with maximum of self-potential anomaly, temperature and radon, and reaching the surface on the highest elevation area along the profile. |
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