1887
Volume 31, Issue 1-2
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

Analytical expressions for the electromagnetic field components at an arbitrary location in a half-space are presented for a vertical magnetic dipole source on the surface of the Earth. The Hankel transforms required in the computation are enumerated using expressions based on the modified Bessel functions of the first and second kind. For surface electromagnetic fields, the Bessel function expressions are shown to consistently produce results that are up to four orders of magnitude more accurate than the results commonly obtained using digital filters. In addition, initial speed tests reveal that considerable computational time is saved compared with the use of numerical routines based on digital filters. It is expected that the increased speed and accuracy of the analytical solution will find application in forward modelling and inversion routines where a half-space is considered to be a suitable model and Hankel transforms need to evaluated many times.

Loading

Article metrics loading...

/content/journals/10.1071/EG00126
2000-03-01
2026-01-19
Loading full text...

Full text loading...

References

  1. Abramowitz, M. and Stegun, I.A., 1970, Handbook of mathematical functions: National Bureau of Standards Applied Mathematics Series.
  2. Anderson, W.L., 1979, Numerical integration of related Hankel transforms of order 0 and 1 by adaptive digital filtering: Geophysics, 44, 1287-1305.
  3. Christensen, N.B., 1990, Optimized fast Hankel transform filters: Geophys. Prosp. 38, 545-568.
  4. Das, U.C. and Verma, S.K., 1982, Electromagnetic response of an arbitrarily shaped three-dimensional conductor in a layered earth-numerical results: Geophys. J. Roy. Astr. Soc., 68, 55-56.
  5. Frischknecht, F.C., Labson, V.F., Spies, B.R. and Anderson, W.L., 1991, Profiling methods using small sources: in Nabighian, M.N., Ed., Electromagnetic methods in applied geophysics: Soc. Expl. Geophys.
  6. Ghosh, D.P., 1971, The application of linear digital filter theory to the direct interpretation of geoelectrical resistivity sounding measurements: Geophys. Prosp., 19, 192-217.
  7. Guptasarma, D. and Singh, B., 1997, New digital linear filters for Hankel J0 and J1 transforms: Geophys. Prosp., 45, 745-762.
  8. Johansen, H.K. and Sorensen, K., 1979, Fast Hankel transforms: Geophys. Prosp., 27, 876-901.
  9. Koefoed, O., 1972, A note on the linear filter method of interpreting resistivity sounding data: Geophys. Prosp., 20, 403-405.
  10. Kumar, R., 1974, Direct interpretation of two-electrode resistivity soundings: Geophys. Prosp., 22, 224-237.
  11. Mohsen, A.A. and Hashish, E.A., 1994, The fast Hankel transform: Geophys. Prosp., 42, 131-139.
  12. Patra, H.P. and Mallick, K., 1980. Geosounding Principles: Elsevier Science Publ. Co. Inc.
  13. Raiche, A.P. and Coggon, J.H., 1975, Analytic Green's tensors for integral equation modelling: Geophys. J. Roy. Astr. Soc., 42, 1035-1038.
  14. Spiegel, M.R., 1968, Mathematical handbook of formulas and tables: McGraw-Hill Book Co.
  15. Spies, B.R. and Frischknecht, F.C., 1991, Electromagnetic sounding: in Nabighian, M.N., Ed., Electromagnetic methods in applied geophysics: Soc. Expl. Geophys Wait, J.R., 1982. Geo-electromagnetism: Academic Press Inc.
  16. Ward, S.H. and Hohmann, G.W., 1991, Electromagnetic theory for geophysical applications: in Nabighian, M.N., Ed., Electromagnetic methods in applied geophysics: Soc. Expl. Geophys.
/content/journals/10.1071/EG00126
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