Parametric 3D inversion of airborne time domain electromagnetics

Time-Domain Algorithms for Computational Electromagnetics

Advances in electromagnetic modeling based on integral equation methods and their application to 3D inversion of time-domain airborne data

Thirty-five years ago, Gerald W. Hohmann, late Professor of Geophysics at The University of Utah, published a seminal paper on 3D electromagnetic (EM) modeling using the integral equation (IE) method. This achievement subsequently inspired a considerable body of research in 3D EM modeling and inversion. Over the decades, the IE method evolved from the academic intrigue of EM fields scattering f...

The 3D inversion of airborne gamma-ray spectrometric data

Gamma radiation measurements are made at airborne survey heights and, through suitable processing, are converted to estimates of the count rates due to the radioelements (K, U and Th) at each observation point along the flight lines. The conventional processing of these data would include a correction for deviations in the aircraft height from the nominal survey height. The elemental count rate...

3D inversion of airborne electromagnetic data using a moving footprint

It is often argued that 3D inversion of entire airborne electromagnetic (AEM) surveys is impractical, and that 1D methods provide the only viable option for quantitative interpretation. However, real geological formations are 3D by nature and 3D inversion is required to produce accurate images of the subsurface. To that end, we show that it is practical to invert entireAEMsurveys to3Dconductivi...

Rapid and rigorous 3D inversion of airborne electromagnetic data

We address the challenging problem of interpreting frequency domain helicopter-borne electromagnetic data in areas with rough topography. Our method is based on localized quasi-linear (LQL) inversion followed by rigorous inversion, if necessary. Terrain corrections are also included. The LQL inversion serves to provide a fast image of the target. These results are checked by rigorous successive...