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THE APPLICATION OF LINEAR FILTER THEORY TO THE DIRECT INTERPRETATION OF GEOELECTRICAL RESISTIVITY SOUNDING MEASUREMENTS *
Author(s) -
GHOSH D. P.
Publication year - 1971
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.1365-2478.1971.tb00593.x
Subject(s) - electrical resistivity and conductivity , depth sounding , vertical electrical sounding , filter (signal processing) , field (mathematics) , mineralogy , function (biology) , geology , interpretation (philosophy) , mathematical analysis , mathematics , physics , geotechnical engineering , computer science , aquifer , engineering , electrical engineering , oceanography , quantum mechanics , evolutionary biology , pure mathematics , groundwater , biology , programming language
A bstract Koefoed has given practical procedures of obtaining the layer parameters directly from the apparent resistivity sounding measurements by using the raised kernel function H (λ) as the intermediate step. However, it is felt that the first step of his method—namely the derivation of the H curve from the apparent resistivity curve—is relatively lengthy. In this paper a method is proposed of determining the resistivity transform T (λ), a function directly related to H (λ), from the resistivity field curve. It is shown that the apparent resistivity and the resistivity transform functions are linearily related to each other such that the principle of linear electric filter theory could be applied to obtain the latter from the former. Separate sets of filter coefficients have been worked out for the Schlumberger and the Wenner form of field procedures. The practical process of deriving the T curve simply amounts to running a weighted average of the sampled apparent resistivity field data with the pre‐determined coefficients. The whole process could be graphically performed within an quarter of an hour with an accuracy of about 2%.