3D resistivity gridding of large AEM datasets: a step toward enhanced geological interpretation

Alexandre Pryet (1) , James Ramm (2) , Jean-Paul Chilès (3) , Esben Auken (2) , Benoît Deffontaines (4) , Sophie Violette (1)

1 SISYPHE - Structure et fonctionnement des systèmes hydriques continentaux
2 HydroGeophysics Group [Aarhus]
3 GEOSCIENCES - Centre de Géosciences
4 GTMC - Géodésie Télédétection et Modélisation des Connaissances

We develop a technique allowing 3D gridding of large sets of 1D resistivity models obtained after inversion of extensive airborne EM surveys. The method is based on the assumption of a layered-earth model. 2D kriging is used for interpolation of geophysical model parameters and their corresponding uncertainties. The 3D grid is created from the interpolated data, its structure accurately follows the geophysical model, providing a lightweight file for a good rendering. Propagation of errors is tracked through the quantification of uncertainties from both inversion and interpolation procedures. The 3D grid is exported to a portable standard, which allows flexible visualization and volumetric computations, and improves interpretation. The method is validated and illustrated by a case-study on Santa Cruz Island, in the Galapagos Archipelago.

Keywords: Airborne electromagnetics; 3D resistivity model; 3D grid; Kriging; Interpolation

Domains: Sciences of the Universe [physics]; Continental interfaces, environment; Environmental Sciences; Global Changes

Alexandre Pryet, James Ramm, Jean-Paul Chilès, Esben Auken, Benoît Deffontaines, et al.. 3D resistivity gridding of large AEM datasets: a step toward enhanced geological interpretation. Journal of Applied Geophysics, 2011, 75, pp.277-283. ⟨10.1016/j.jappgeo.2011.07.006⟩. ⟨hal-00694658v2⟩