Details of the abstract
| Title of paper | 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 |
| List of authors | Mathieu Darnet1, Pierre Wawrzyniak1, Pascal Tarits2, Sophie Hautot3 and Jean-François D’eu4 |
| Affiliation(s) |
1BRGM – French Geological Survey, Orléans, France – m.darnet@brgm.fr or p.wawrzyniak@brgm.fr 2IUEM, Institut Universitaire Européen de la Mer, LGO, UMR 6538 - IUEM/UBO - pascal.tarits@univ-brest.fr 3 IMAGIR Sarl, Saint Renan, France - sophie.hautot@imagir.eu 4 MAPPEM Geophysics SAS, Saint Renan, France - jf.deu@mappem-geophysics.com |
| Summary | 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. |
| Session Keyword | 4.0 Tectonics, Magmatism, Geodynamics |
| File upload |
4.0_mapping_the_geometry_of_v_darnet.pdf
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