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THE INFLUENCE OF ELECTRICAL ANISOTROPY ON MISE À LA MASSE SURVEYS *
Author(s) -
ASTEN M. W.
Publication year - 1974
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.1365-2478.1974.tb00082.x
Subject(s) - anisotropy , geology , electrical resistivity and conductivity , displacement (psychology) , electrode , mineralogy , rock mass classification , ellipse , geophysics , optics , geometry , chemistry , physics , geotechnical engineering , psychology , mathematics , quantum mechanics , psychotherapist
A bstract In a transversely electrically anisotropic rock mass of arbitrary dip, the potential distribution about an electrode at arbitrary depth is the sum of the whole‐space potential about that electrode, plus the whole‐space potential about a postulated image electrode displaced up‐dip from the source position. Equipotential lines on the rock‐air surface are ellipses, elongated parallel to strike, and with centers displaced up‐dip from the surface projection of the electrode position. In metamorphosed rocks frequently encountered in mining geophysics, anisotropy is such that elongation is most marked in steeply dipping rocks, with displacement most evident in low to moderate dip. Graphs relating the anisotropy coefficient to displacement and elongation assist in separation of the anisotropy‐related effects from those of a significant subsurface conductive body, particularly if surface resistivity sounding establishes the coefficient of anisotropy.