1887

Abstract

Summary

Recently, an airborne time-domain electromagnetic (ATEM) surveying with a grounded source, called GREATEM, has gained popularity because it provides a greater depth of investigation than moving-source ATEM surveys. However, unlike moving-source ATEM responses, GREATEM responses exhibit complicated behaviors that result from galvanic currents rather than vortex currents. Our model study showed that 1D inversion of GREATEM data is most likely to result in an erroneous resistivity model even for layered structures if there are some lateral changes in layer thickness and that 3D inversion is required to recover the subsurface resistivity. Our 3D modeling is based on a finite-difference technique in the frequency domain and inverse Fourier transformation to the time-domain response. The convolution with the system response is performed in the frequency domain. For 3D inversion, we introduced a scaling factor as an unknown parameter to take into account inaccuracies in the source moment and receiver gain. The inversion algorithm has been tested with a simple 3D subsurface model and 3D inversion result for a field data set taken over a known uranium deposit in Korea showed that the recovered conductive zones are consistent with the known structural direction and distribution of mineralization zones.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201802709
2018-09-09
2020-05-28
Loading full text...

Full text loading...

References

  1. 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.
    [Google Scholar]
  2. Mogi, T., Kusunoki, K., Kaieda, H., Ito, H., Jomori, A., Jomori, N., and Yuuki, Y.
    , 2009, Grounded electrical-source airborne transient electromagnetic (GREATEM) survey of Mount Bandai, northeastern Japan, Exploration Geophysics, 40, 1–7.
    [Google Scholar]
  3. Newman, G.A., and Alumbaugh, D.L.
    , 1995, Frequency-domain modeling of airborne electromagnetic responses using staggered finite differences, Geophysical Prospecting, 43, 1021–1042.
    [Google Scholar]
  4. Sasaki, Y., Yi, M.-J., Choi, J., and Son, J.-S.
    , 2015, Frequency and time domain three-dimensional inversion of electromagnetic data for a grounded-wire source, Journal of Applied Geophysics, 112, 106–114.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201802709
Loading
/content/papers/10.3997/2214-4609.201802709
Loading

Data & Media loading...

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