1887
  1. Home
  2. Conferences
  3. Conference Proceedings
  4. NSG2022 3rd Conference on Airborne, Drone and Robotic Geophysics
  5. Conference paper

Abstract

Summary

The inversion of time-domain AEM data with full 3D inversion requires specialists’ expertise and a huge amount of computational resources, not readily available to everyone. Consequently, quasi-2D/3D inversion methods are prevailing, using a much faster but approximate (1D) forward model. The question remains whether the obtained inversion results are reliable and can be interpreted quantitatively. We propose an appraisal tool for quasi-2D/3D methods that indicate zones in the inversion model that are not in agreement with the multidimensional (2D/3D) forward model and therefore, should not be interpreted in a quantitative fashion.

The image appraisal step only requires one full 2.5D or 3D forward and one multidimensional Jacobian computation on a coarse mesh to compute a so-called normalized gradient. Large values in that gradient indicate model parameters that do not fit the true multidimensionality of the observed data well and should not be interpreted quantitatively. We demonstrate our method on a real AEM survey in a salinization context, revealing problematic zones in the fresh-saltwater interface. Interestingly, the problematic zones are not necessarily at larger depths, but where the interface is changing. The advantage of our approach is that all computations are feasible on a single laptop.

© EAGE Publications BV
Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.202220024
2022-09-18
2024-10-09

  • From This Site

    /content/papers/10.3997/2214-4609.202220024
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Alumbaugh, D.L. and Newman, G.A. [2000] Image appraisal for 2-D and 3-D electromagnetic inversion. Geophysics, 65(5), 1455–1467.
     [Google Scholar]
  2. Auken, E., Boesen, T. and Christiansen, A.V. [2017] A review of airborne electromagnetic methods with focus on geotechnical and hydrological applications from 2007 to 2017. Advances in Geophysics, 58, 47–93.
     [Google Scholar]
  3. Christiansen, A.V. and Christensen, N.B. [2003] A quantitative appraisal of airborne and ground-based transient electromagnetic (TEM) measurements in Denmark. Geophysics, 68(2), 523–534.
     [Google Scholar]
  4. Constable, S.C., Parker, R.L. and Constable, C.G. [1987] Occam’s inversion: A practical algorithm for generating smooth models from electromagnetic sounding data. Geophysics, 52(3), 289–300.
     [Google Scholar]
  5. Cox, L.H., Wilson, G.A. and Zhdanov, M.S. [2010] 3D inversion of airborne electromagnetic data using a moving footprint. Exploration Geophysics, 41(4), 250–259.
     [Google Scholar]
  6. Delsmans, J., van Baaren, E., Vermaas, T., Karaoulis, M., Bootsma, H., de Louw, P., Pauw, P., Oude Es-sink, G., Dabekaussen, W., Van Camp, M., Walraevens, K., Vandenbohede, A., Teilmann, R. and Thofte, S. [2019] TOPSOIL Airborne EM kartering van zoet en zout grondwater in Vlaanderen. Tech. rep., VMM.
     [Google Scholar]
  7. Engebretsen, K.W., Zhang, B., Fiandaca, G., Madsen, L.M., Auken, E. and Christiansen, A.V. [2022] Accelerated 2.5-D inversion of airborne transient electromagnetic data using reduced 3-D meshing. Geophysical Journal International, 230(1), 643–653.
     [Google Scholar]
  8. Heagy, L.J., Cockett, R., Kang, S., Rosenkjaer, G.K. and Oldenburg, D.W. [2017] A framework for simulation and inversion in electromagnetics. Computers & Geosciences, 107, 1–19.
     [Google Scholar]
  9. Werthmüller, D. [2017] An open-source full 3D electromagnetic modeler for 1D VTI media in Python: empymod. GEOPHYSICS, 82(6), WB9–WB19.
     [Google Scholar]
  10. Zhang, B., Engebretsen, K.W., Fiandaca, G., Cai, H. and Auken, E. [2021] 3D inversion of time-domain electromagnetic data using finite elements and a triple mesh formulation. Geophysics, 86(3), E257–E267.
     [Google Scholar]
/content/papers/10.3997/2214-4609.202220024
Loading
Assessing Quantitatively Interpretable Zones From 1D Forward Modelling Aem Inversion Models
Conference Proceedings 2022, 1 (2022); https://doi.org/10.3997/2214-4609.202220024
/content/papers/10.3997/2214-4609.202220024
/content/papers/10.3997/2214-4609.202220024
Loading

Data & Media loading...

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error