Evaluation of Resistivity Anisotropy of Parts of Ijebu Igbo, Southwestern, Nigeria Using Azimuthal Resistivity Survey (ARS) Method

Bayewu Olateju O,Folorunso Ismail O,Kolawole Ajibola U,Mosuro Ganiyu O,Oloruntola Moroof O

doi:10.5539/jgg.v6n4p140

Abstract

This study was carried out to determine the anisotropic properties of parts of the Southwestern Basement Complex of Nigeria in Ijebu Igbo, which is underlain by migmatite gneiss and older granites.The surface water level (SWL) of 107 hand-dug wells were measured to determine the groundwater flow direction of the area. Thirty Azimuthal Resistivity Survey (ARS) were investigated along four azimuths; 0°, 45°, 90°, and 135° to determine the electrical anisotropy, the trend of fractures and their behavioural pattern with depth. The quantitative interpretation of the Radial Vertical Electrical Sounding (RVES) curves involved the use of partial curve matching, and computer iteration using WINRESIST program ...

Highlights

Electrical resistivity anisotropy for geological prospecting has not been extensively used in surface geophysics despite the usefulness of electrical methods for detecting fluid - filled fractures (Mamah and Ekine, 1989, Olasehinde and Bayewu, 2011)
Surface geophysical techniques can be an invaluable tool in mapping the structural features of the concealed crystalline basement rocks (Olorunfemi and Opadokun, 1987) and in the detection of microfabrics resulting from basement tectonic in sedimentary terrain (Mamah and Ekine, 1989)
The surface water level was calculated from the difference between the well water depth and the elevation from the Google Earth software

Summary

Introduction

Electrical resistivity anisotropy for geological prospecting has not been extensively used in surface geophysics despite the usefulness of electrical methods for detecting fluid - filled fractures (Mamah and Ekine, 1989, Olasehinde and Bayewu, 2011). Electrical anisotropy of crystalline basement rocks is often attributed to structural elements like foliations, joints and fractures (Billings 1972; Malik, et al, 1983). It has been shown by Odeyemi, et al, (1985); Beeson and Jones, (1988); Esu, (1993) and Edet et al, (1994) that the well yield and its direction flow in fractured rocks is directly related to the density, frequency, orientation and inter-connection of structural features at depth

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