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

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.

► We present a method to build 3D grids of resistivity from 1D vertical models.
► It is designed for airborne TEM and FEM surveys inversed to 1D models.
► Geophysical model parameters are interpolated in 2D by kriging.
► Uncertainties from both inversion and interpolation are quantified.
► The 3D grid allows 3D visualization and volumic computations.