3D imaging of subsurface magnetic permeability / susceptibility with portable frequency domain electromagnetic sensors for near surface exploration

Autor: Guillaume Hulin, Julien Guillemoteau, Jens Tronicke, François-Xavier Simon, Marion Dacko, Bertrand Dousteyssier
Přispěvatelé: Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Institut national de recherches archéologiques préventives (Inrap), Centre d'Histoire 'Espaces et Cultures' (CHEC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Maison des Sciences de l'Homme - Clermont Auvergne (MSH Clermont), Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Institute of Earth and Environmental Science [Potsdam], University of Potsdam, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Maison des Sciences de l'Homme de Clermont-Ferrand (MSH Clermont), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement (UMR 6249) (LCE), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Potsdam = Universität Potsdam, Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Geophysical Journal International
Geophysical Journal International, Oxford University Press (OUP), 2020, ⟨10.1093/gji/ggz382⟩
Geophysical Journal International, Oxford University Press (OUP), 2019, 219 (3), pp.1773-1785. ⟨10.1093/gji/ggz382⟩
Geophysical Journal International, 2019, 219 (3), pp.1773-1785. ⟨10.1093/gji/ggz382⟩
ISSN: 0956-540X
1365-246X
DOI: 10.1093/gji/ggz382⟩
Popis: SUMMARY The in-phase response collected by portable loop–loop electromagnetic induction (EMI) sensors operating at low and moderate induction numbers (≤1) is typically used for sensing the magnetic permeability (or susceptibility) of the subsurface. This is due to the fact that the in-phase response contains a small induction fraction and a preponderant induced magnetization fraction. The magnetization fraction follows the magneto-static equations similarly to the magnetic method but with an active magnetic source. The use of an active source offers the possibility to collect data with several loop–loop configurations, which illuminate the subsurface with different sensitivity patterns. Such multiconfiguration soundings thereby allows the imaging of subsurface magnetic permeability/susceptibility variations through an inversion procedure. This method is not affected by the remnant magnetization and theoretically overcomes the classical depth ambiguity generally encountered with passive geomagnetic data. To invert multiconfiguration in-phase data sets, we propose a novel methodology based on a full-grid 3-D multichannel deconvolution (MCD) procedure. This method allows us to invert large data sets (e.g. consisting of more than a hundred thousand of data points) for a dense voxel-based 3-D model of magnetic susceptibility subject to smoothness constraints. In this study, we first present and discuss synthetic examples of our imaging procedure, which aim at simulating realistic conditions. Finally, we demonstrate the applicability of our method to field data collected across an archaeological site in Auvergne (France) to image the foundations of a Gallo-Roman villa built with basalt rock material. Our synthetic and field data examples demonstrate the potential of the proposed inversion procedure offering new and complementary ways to interpret data sets collected with modern EMI instruments.
Databáze: OpenAIRE
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