Comparison of Six Classical Electrode Arrays of 1D Resistivity Survey for Subsurface Delineation – Field Experiments
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Date
2020
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Publisher
University of Ilorin, Nigeria
Abstract
Six classical Traditional Resistivity Survey methods comprising Schlumberger, Wenner, Dipole-dipole, Wenner-Schlumberger, Pole-dipole and Pole-pole arrays were tested for subsurface stratigraphic delineation in a series of field experiments conducted in the basement complex area of Ilorin, North central Nigeria. The aim of the study is to determine the suitability, strength, and weakness of the different array system for subsurface stratigraphic delineation. Interpretations and comparisons of results from the different arrays were based on the lithologic sections obtained from borehole drillers’ logs in the study area. The results of the study showed that some arrays are more reliable for geo-electric layer delineation than others. Wenner-Schlumberger and Schlumberger arrays gave the overall best results in terms of estimating the vertical extent of layers and depth to hard rock (fresh basement rock). Wenner-Schlumberger array proved to be a reasonable alternative to Schlumberger array when strong vertical resolution is needed. Dipole-dipole, pole-dipole, and Wenner arrays consistently underestimate the number of horizontal layers in most of the study locations, thereby suggesting low sensitivity of the methods to vertical resistivity changes. In situations where the four electrodes cannot be situated within the vicinity of the target, results of the study showed also that pole-pole rather than pole-dipole is a better method of resistivity survey. Interestingly, none of the methods is one hundred percent accurate when compared to the borehole lithologic sections. The study recommends Schlumberger and Wenner-Schlumberger methods for high-resolution subsurface delineation in the study area. Descriptions of the field procedure and electrodes arrangement for the six classical arrays are detailed in this paper with the goal of providing guides to non-professional geophysicists like Agriculturists, Civil and Water engineers, and new-comers in the discipline of geosciences who sometimes engage traditional methods of resistivity survey for testing soil and concrete material and citing water-wells /boreholes.
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Keywords
Wenner array, Schlumberger array, Dipole-dipole array, Pole-pole array, Dipole-pole array, Pole-dipole array, Geo-electric parameters
Citation
Raji W. O, Ibitoye PE, Abiri OA, Adepoju JA, Abdulkadir KA (2020). Comparison of Six Classical Electrode Arrays of 1D Resistivity Survey for Subsurface Delineation – Field Experiments. Centre Point Journal, 26(1), 79-97.