Application of Electrical Resistivity in Mapping Subsurface Characteristics

Abstract

The subsurface is made up of different geologic materials occurring at various depths. In basement terrain, the lithological unit that can be noticed made up of the weathered layer, weathered/fractured basement, and fresh basement. This research applied the application of vertical electrical sounding (VES) method to locate subsurface structures of Iseyin town with coordinate 7.580N and 3.357E. A total of twenty VES using Schlumberger array, the field data obtained were analyzed and interpreted using Win-resist software and the simulated results were processed using surfer 8. The results revealed that the area was characterized by four classes of geo-electrical layers which are top soil (clay, sandy clay, clay sand) with resistivity and thickness values ranges from 43.4Ωm - 819.7Ωm and 0.3m - 6.1m, lateritic layer ranges from 28.1Ωm - 846.0Ωm and 1.2m - 20.7m, weathered/fractured layer ranges from 15.6Ωm - 405.0Ωm and 4.6m - 55.2m, fresh rock with resistivity > 1000Ωm at infinity thickness. From the obtained results, lateritic layer and weathered/fracture layer are the saturated zone (alluvium) which shows that borehole drilling in this area is achievable at a depth of 38.6m which allow big reservoir within the aquifer unit and overburden is thick enough for the aquifer to accommodate high ground water potential.