Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: 3D Electrical Resistivity Tomography (ERT) Survey of a Typical Basement Complex Terrain
by B.S. Badmus, O.D. Akinyemi, J.A. Olowofela and G.M. Folarin

Abstract:
A 49-electrode system was used in the Electrical Resistivity Tomography (ERT) survey in three locations with each location marked into 7 by 7 square grids for the electrodes using 1.0m, 3.0m and 5.0m unit electrode spacings in succession. The pole-pole electrode array was used with the two remote electrodes placed at distances of 23m, 40m and 65m from the grids with 1.0m, 3.0m and 5.0m unit electrode spacing respectively to reduce their telluric effects on the apparent resistivity values measured. The data obtained were analysed and 3D models of the subsurface were generated using 3D inversion software called RES3DINV and the Slicer Dicer software. The result from this study was found to be similar to those from the studies for which multi-channel 3D equipment were used. The results of the interpretation revealed the Lithology to compose lateritic soil, sand, sandstone, sandy clay and clay. The results also showed that the three different unit electrode spacing displayed similar geo-electric models and the electrode spacing determines the depths of investigation. Geological structures are 3-Dimensional (3D) in nature, thus 1-Dimensional and 2-Dimensional surveys cannot adequately model them. However, sophisticated 3D survey equipment is very expensive and not readily available. This prompted the use of a single-channel SAS 300B Terrameter to obtain a 3D model of the subsurface.

Keywords: resistivity, tomography, 3D models, electrode spacing, geo-electric layer

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