Volume 36 Number 4
  • E-ISSN: 1365-2478



A complex transfer function (or generalized skin depth) can be derived from data for the secondary magnetic field measured by a dipole system with small coil spacing at height above the ground. This function has a useful property: For a uniform or layered ground, the real part of yields the‘ centroid depth’* of the in‐phase current system as a function of frequency.

This parameter can be combined with the apparent resistivity derived by conventional methods. The function (*), if known over a broad frequency range, yields a smoothed approximation of the true distribution () without an initial model. The relations between (*) and () are studied for a number of multilayer models. An example of the application of the *) algorithm to data from a groundwater survey is given.


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  • Article Type: Research Article
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