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SIMPLE DATA PROCESSING OF TRIPOTENTIAL APPARENT RESISTIVITY MEASUREMENTS AS AN AID TO THE INTERPRETATION OF SUBSURFACE STRUCTURE *
Author(s) -
ACWORTH R. I.,
GRIFFITHS D. H.
Publication year - 1985
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.1365-2478.1985.tb00782.x
Subject(s) - electrical resistivity and conductivity , geology , economic geology , gemology , regional geology , mineralogy , data processing , environmental geology , interpretation (philosophy) , igneous petrology , range (aeronautics) , soil science , engineering geology , geophysics , hydrogeology , materials science , geotechnical engineering , seismology , metamorphic petrology , physics , computer science , quantum mechanics , volcanism , tectonics , programming language , operating system , composite material
A bstract The advantages of the Wenner tripotential method (Carpenter 1955) for apparent resistivity profiling are described and two new data processing techniques introduced as an aid to the interpretation of apparent resistivity sections (pseudo‐sections). These techniques were developed from model data computed using a two‐dimensional finite difference method. Oscillatory components present in anomalies on tripotential profiles and related to electrode spacing are shown to be effectively removed by linear filtering that also simplifies their form and aids recognition. Furthermore, it is shown that the ratio of the beta‐ and gamma‐apparent resistivities is a good indicator of resistivity variation, and is particularly sensitive to lateral change. Model data indicates that, over a wide range of conditions, enough subsurface information can be obtained by inspection of tripotential resistivity and ratio profiles, and from space sections to make possible a useful—and sometimes semi‐quantitative—interpretation. A rationale for the general interpretation of tripotential data is developed. Field data are described from an area of weathered granite basement in Nigeria. A model of the subsurface is developed using parameters derived from the processed observations. The observed and calculated apparent resistivity space sections are very similar.