1887
Volume 32 Number 3
  • E-ISSN: 1365-2478

Abstract

A

A thin superparamagnetic layer on the earth's surface greatly affects the transient electromagnetic response of a conducting ground. The effect of the layer is most evident for singleloop transient electromagnetic data where transient voltages decay as 1/. Even when a separate transmitter and receiver are used, the effect of the superparamagnetic layer is still pronounced. In this case the effect of the 1/ term in the equation is much less. More dominant now is a 1/2 term. The effect of the superparamagnetism can readily be seen in the analytical expressions for the apparent resistivities. If the presence of the superparamagnetic layer is not recognized, then the apparent resistivities decrease with time rather than approach the true value of the host rock.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.1984.tb01111.x
2006-04-27
2024-04-25
Loading full text...

Full text loading...

References

  1. Abramowitz, M.
    and Stegun, I. A. , (eds.) 1965, Handbook of Mathematical Functions, Dover, New York .
    [Google Scholar]
  2. Buselli, G.1982, The effect of near surface superparamagnetic material on electromagnetic transients, Geophysics47, 1315–1324.
    [Google Scholar]
  3. Byrd, P. F. and Friedman, M. D.1954, Handbook of Elliptic Integrals for Engineers and Physicists, Springer‐Verlag, Berlin , Heidelberg , New York .
    [Google Scholar]
  4. Chikazumi, S. and Charap, S. H.1978, Physics of Magnetism, Robert E. Krieger, Huntington , New York .
    [Google Scholar]
  5. Gradshteyn, J. S. and Ryzhik, I. M.1980, Tables of Integrals, Series and Products, Academic Press, New York , London .
    [Google Scholar]
  6. Lee, T.1977, Estimation of depth to conductors by the use of electromagnetic transients, Geophysical Prospecting25, 61–75.
    [Google Scholar]
  7. Lee, T.1981a, Transient electromagnetic response of a polarizable ground, Geophysics46, 1037–1041.
    [Google Scholar]
  8. Lee, T. J.1981b, Evaluation of a class of integrals occurring in mode matching solutions for electrical and electromagnetic modelling, Geophysical Journal of the Royal Astronomical Society66, 455–460.
    [Google Scholar]
  9. Lee, T. and Lewis, R.1974, Transient EM response of a large loop on a layered ground, Geophysical Prospecting22, 430–444.
    [Google Scholar]
  10. Magnus, W., Oberhettinger, F. and Soni, R. P.1966, Formulas and Theorems for the Special Functions of Mathematical Physics, Springer‐Verlag, Berlin , Heidelberg , New York .
    [Google Scholar]
  11. Morrison, H. F., Phillips, R. J. and O'Brien, D. P.1969, Quantitative interpretation of transient electromagnetic fields over a layered halfspace, Geophysical Prospecting17, 82–101.
    [Google Scholar]
  12. Oberhettinger, F. and Badii, L.1973, Tables of LaPlace Transforms, Springer‐Verlag, Berlin , Heidelberg , New York .
    [Google Scholar]
  13. Wait, J. R.1962, Theory of magnetotelluric fields, Journal of National Bureau of Standards Radio Propagation 66D5, 509–541.
    [Google Scholar]
  14. Weidelt, P.1982, Response characteristics of coincident loop transient electromagnetic systems, Geophysics47, 1325–1330.
    [Google Scholar]
  15. Wheelan, A. D.1968, Tables of Summable Series and Integrals Involving Bessel Functions, Holden Day, San Francisco .
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.1984.tb01111.x
Loading
  • Article Type: Research Article

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