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APPROXIMATE INVERSION OF AIRBORNE EM DATA FROM A MULTILAYERED GROUND 1
Author(s) -
SENGPIEL K.P.
Publication year - 1988
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1988.tb02173.x
Subject(s) - transfer function , inversion (geology) , range (aeronautics) , centroid , electrical resistivity and conductivity , computational physics , geology , groundwater , dipole , function (biology) , economic geology , regional geology , physics , geometry , hydrogeology , materials science , mathematics , seismology , telmatology , engineering , quantum mechanics , evolutionary biology , biology , electrical engineering , composite material , tectonics , geotechnical engineering , metamorphic petrology
A complex transfer function c (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 h above the ground. This function has a useful property: For a uniform or layered ground, the real part of c yields the‘ centroid depth’ z * of the in‐phase current system as a function of frequency. This parameter can be combined with the apparent resistivity ρ a derived by conventional methods. The function ρ a ( z *), if known over a broad frequency range, yields a smoothed approximation of the true distribution ρ ( z ) without an initial model. The relations between ρ a ( z *) and ρ ( z ) are studied for a number of multilayer models. An example of the application of the ρ a *) algorithm to data from a groundwater survey is given.