1887
Volume 37, Issue 4
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

2.5D electromagnetic (EM) modelling computes the response of a 3D source from an arbitrary 2D geoelectrical model. As such, it is practical for airborne EM (AEM) data to be inverted using 2.5D modelling provided that the geoelectrical cross-section is relatively constant along a strike length that exceeds the AEM system footprint. The program is introduced for modelling and inversion based on a 2D finite-element method that enables the accurate simulation of 3D source excitation for full domain models inclusive of topography, non-conforming boundaries, and very high resistivity contrasts. Inversion is based on an iterative Gauss-Newton method that is solved using the damped eigenparameter algorithm. Examples are presented for synthetic and practical frequency and time-domain AEM surveys for which inversion run-times are on the order of hours.

Loading

Article metrics loading...

/content/journals/10.1071/EG06363
2006-12-01
2026-01-18
Loading full text...

Full text loading...

References

  1. Annetts, D., Sugeng, F., and Raiche, A., 2003, Modelling and matching the airborne EM response of Harmony and Maggie Hays: 16th Geophysical Conference and Exhibition, Australian Society of Exploration Geophysicists, Expanded Abstracts.
  2. Chen, J., and Raiche, A., 1998, Inverting AEM data using a damped eigenparameter method: Exploration Geophysics , 29, 128-132.
  3. Chen, J., Raiche, A., Sugeng, F., and Macnae, J., 1998, 2.5D conductivity inversion of airborne EM data: 68th Annual International Meeting, Society of Exploration Geophysicists, Expanded Abstracts , 756-759.
  4. Ellis, R.G., 1995, Joint 3D EM inversion: International Symposium on Three-Dimensional Electromagnetics, Expanded Abstracts , 307-323.
  5. Ellis, R. G., 1998, Inversion of airborne electromagnetic data: Exploration Geophysics , 29, 121-127.
  6. Everett, M.E., and Edwards, R.N., 1993, Transient marine electromagnetics: the 2.5-D forward problem: Geophysical Journal International , 113, 545-561.
  7. Hodges, G., 2001, Technical Notes - Helicopter Electromagnetics: [Web document]: Accessed June, 2006. Available at < http://www.fugroairborne.com>
  8. Irons, B.M., 1970, A frontal solution program for finite-element analysis: International Journal of Numerical Methods , 2, 5-32.
  9. Jupp, D.L.B., and Vozoff, K., 1975, Stable iterative methods for geophysical inversion: Geophysical Journal of the Royal Astronomical Society , 42, 55-72.
  10. Macnae, J., King, A., Stolz, N., Osmakoff, A., and Blaha, A., 1998, Fast AEM data processing and inversion: Exploration Geophysics , 29, 163-169.
  11. McGillivray, P.R., Oldenburg, D.W., Ellis, R.G., and Habashy, T.M., 1994, Calculation of sensitivities for the frequency-domain electromagnetic problem: Geophysical Journal International , 116, 1-4.
  12. Naldrett, A.J., Keats, H., Sparkes, K., and Moore, R., 1996, Geology of the Voisey’s Bay Ni-Cu-Co deposit, Labrador, Canada: Exploration and Mininig Geology , 5, 169-179.
  13. Raiche, A., 1998, Modelling the time-domain response of AEM systems: Exploration Geophysics , 29, 103-106.
  14. Raiche, A.P., Jupp, D.L.B., Rutter, H., and Vozoff, K., 1985, The joint use of coincident loop transient electromagnetic and Schlumberger sounding to resolve layered structures: Geophysics , 50, 1618-1627.
  15. Raiche, A., Sugeng, F, and Annetts, D., 2001, Finding targets in complex hosts using airborne EM: 15th Geophysical Conference and Exhibition, Australian Society of Exploration Geophysicists, Expanded Abstracts.
  16. Stoyer, C.H., and Greenfield, R.J., 1976, Numerical solutions of the response of a two-dimensional earth to an oscillating magnetic dipole: Geophysics , 41, 519-530.
  17. Sugeng, F, Raiche, A. R, and Rijo, L., 1993, Comparing the time-domain EM response of 2-D and elongated 3-D conductors excited by a rectangular loop source: Journal of Geomagnetism and Geoelectricitiy , 45, 873-885.
  18. Sugeng, F., Xiong, Z., and Raiche, A., 1995, Comparative modelling of the response of long strike length targets at various contrasts: Internationtal Symposium on Three-Dimensional Electromagnetics, Expanded Abstracts , 553.
  19. Unsworth, M. J., and Oldenburg, D. W., 1995, Subspace inversion of EM data: applications to mid-oceanic ridge exploration: Geophysical Journal International , 123, 161-168.
  20. Unsworth, M.J., Travis, B.J., and Chave, A.D., 1993, Electromagnetic induction by a finite electric dipole source over a 2-D earth: Geophysics , 58, 198-214.
  21. Witherly, K. E., Irvine, R. J., and Raiche A., 2003, The application of airborne electromagnetics to the search for high conductance targets: 16th Geophysical Conference and Exhibition, Australian Society of Exploration Geophysicists, Expanded Abstracts.
  22. Zhdanov, M.S., and Chemyavskiy, A., 2004, Rapid three-dimensional inversion of multi-transmitter electromagnetic data using the spectral Lanczos decomposition method: Inverse Problems , 20, S233-S256.
  23. Zhdanov, M.S., and Tartaras, E., 2002, Inversion of multi-transmitter 3D electromagnetic data based on the localized quasi-linear approximation: Geophysical Journal International , 148, 506-519.
/content/journals/10.1071/EG06363
Loading
  • Article Type: Research Article
Keyword(s): 2.5D; airborne; electromagnetic; inversion; modelling

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