Induced polarization

Induced polarization (IP) is a geophysical imaging technique used to identify the electrical chargeability of subsurface materials, such as ore.[1] The method is similar to electrical resistivity tomography, in that an electric current is transmitted into the subsurface through two electrodes, and voltage is monitored through two other electrodes.

Time domain measurements

Typical transmitted current waveform and potential response for time domain resistivity and induced polarization measurements.

Time domain IP methods measure considers the resulting voltage following a change in the injected current. The time domain IP potential response can be evaluated by considering the mean value on the resulting voltage, known as integral chargeability[1] or by evaluating the spectral information and considering the shape of the potential response, for example describing it with a Cole-Cole model.[2]

Frequency domain measurements

Frequency domain IP methods (see Spectral Induced Polarisation) use alternating currents (AC) to induce electric charges in the subsurface, and the apparent resistivity is measured at different AC frequencies.

References

  1. 1 2 K. Zonge; J. Wynn; S. Urquhart (2005). 9. Resistivity, Induced Polarization, and Complex Resistivity. Society of Exploration Geophysicists. pp. 265–300.
  2. ↑ Pelton, W. H.; Ward, S. H.; Hallof, P. G.; Sill, W. R.; Nelson, P. H. "MINERAL DISCRIMINATION AND REMOVAL OF INDUCTIVE COUPLING WITH MULTIFREQUENCY IP". GEOPHYSICS. 43 (3): 588–609. doi:10.1190/1.1440839.

Further reading

External links


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