Publication 14

On the equivalence of the ``Niblett'' and ``Bostick'' transformations in the magnetotelluric method

Alan G. Jones


In the 1D interpretation of magnetotelluric data, it is often useful to discover a reasonable first-approximation to the true conductivity-depth distribution beneath the recording location. This may be undertaken in the field, in order to ascertain if the station spacing is satisfactory or whether a greater station density of coverage is required, or at the base laboratory, as a prelude to a more sophistocated 1D inversion of the data. There are three approximations presently in use by workers whose interest lies in the conductivity structure of the earth: (1) the Schmucker rho*-z* scheme (Schmucker, 1970); (2) the Bostick transformation (Bostick, 1977); and (3) the Niblett approximation (Niblett and Sayn-Wittgenstein, 1960). The first two are in widespread use in western Europe and north America, whilst the Niblett approximation appears to be strongly favoured in eastern Europe and the USSR. Weidelt et al. (1980) have previously detailed the relationship between Schmucker's rho*-z* and. Bostick's transformation; it is the purpose of this letter to demonstrate that Bostick's transformation and Niblett's approximation are very equivalent - they give exactly the same resistivity-depth profiles!


Journal of Geophysics (Zeitschrift fuer Geophysik), 53, 72-73.

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Alan G Jones / 28 February 2010 /