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DEPTH OF INVESTIGATION IN RESISTIVITY METHODS USING LINEAR ELECTRODES *
Author(s) -
APPARAO A.,
RAO T. GANGADHARA
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.tb00080.x
Subject(s) - electrode , diagram , electrical resistivity and conductivity , materials science , homogeneous , analytical chemistry (journal) , mineralogy , optics , geology , geometry , chemistry , physics , mathematics , thermodynamics , statistics , chromatography , quantum mechanics
A bstract Depths of investigation for normal (bipolar) and focusing (unipolar) linear electrode arrays have been computed following the method given earlier (Roy and Apparao 1971) both in homogeneous and layered earth. The focusing arrangement is found to be superior to normal arrangement both in regard to depth of investigation and zone of uniform depth of investigation. This analysis holds good in layered media too. Further, the depth of investigation increases with the increase in the length (2 M ) of the electrode and reaches a limit, 0.29 L for normal and 0.50 L for focusing, when the electrode attains an optimum length to satisfy the infinite condition. This optimum length of the electrode is six times the distance L of the observation point from the electrode for normal and about ten times for focusing. A contour diagram for contributions of individual ground elements to the total signal measured at the centre of focused system is also discussed.