Mapping the geometry of volcanic systems with magnetotelluric soundings: Results from a land and marine magnetotelluric survey performed during the 2018–2019 Mayotte seismovolcanic crisis

Type Article
Date 2020-11
Language English
Author(s) Darnet M.1, Wawrzyniak P.1, Tarits Pascal2, 3, 4, Hautot S.3, D'Eu J.F.4
Affiliation(s) 1 : BRGM, Bureau des Recherches Géologiques et Minières, 3 av. Claude-Guillemin, BP 36009, 45060 Orléans Cedex 2, France
2 : IUEM, Institut Universitaire Européen de la Mer, LGO, UMR 6538 - IUEM/UBO, Place Nicolas Copernic, Plouzané, 29280, France
3 : IMAGIR Sarl, Tech-Iroise, ZA de Mespaol 2, 1 rue des Ateliers, 29290 Saint Renan,France
4 : MAPPEM Geophysics SAS, Marine Electromagnetic Investigation, Batiment Tech-Iroise, 1 rue des Ateliers, Zone de Mespaol, 29290 Saint-Renan, France
Source Journal Of Volcanology And Geothermal Research (0377-0273) (Elsevier BV), 2020-11 , Vol. 406 , P. 107046 (7p.)
DOI 10.1016/j.jvolgeores.2020.107046
WOS© Times Cited 2
Keyword(s) Magnetotelluric, Electrical resistivity, Seismovolcanic, Geothermal
Abstract

A major seismovolcanic crisis has afflicted the islands of Mayotte, Comoros Archipelago, since May 2018, although the origin is debated. Magnetotellurics (MT), which is sensitive to hydrothermal and/or magmatic fluids and can map the subsurface electrical resistivity structure, can provide insight by revealing the internal structure of the volcanic system. In this paper, we report the results of a preliminary land and shallow marine MT survey performed on and offshore the island nearest the crisis. The 3D inversion-derived electrical resistivity model suggests that the island is underlain by a shallow ~500-m-thick conductive layer atop a deeper, more resistive layer, possibly associated with a high-temperature geothermal system. At depths of ~15 km, the resistivity drops by almost two orders of magnitude, possibly due to partial melting. Further petrophysical and geophysical studies are underway for confirmation and to map the geometry and evolution of the volcanic system.

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Darnet M., Wawrzyniak P., Tarits Pascal, Hautot S., D'Eu J.F. (2020). Mapping the geometry of volcanic systems with magnetotelluric soundings: Results from a land and marine magnetotelluric survey performed during the 2018–2019 Mayotte seismovolcanic crisis. Journal Of Volcanology And Geothermal Research, 406, 107046 (7p.). Publisher's official version : https://doi.org/10.1016/j.jvolgeores.2020.107046 , Open Access version : https://archimer.ifremer.fr/doc/00649/76113/