Electromagnetic Profiling and Electrical Resistivity Soundings For Groundwater Investigation In A Typical Basement Complex: A Case Study of Part of Ijero-Ekiti, Southwestern Nigeria
Integrated geophysical techniques involving Very Low Frequency Electromagnetic Method (VLF – EM) profiling and Electrical Resistivity method using the Vertical Electrical Sounding (VES) technique have been used to map College of Health Sciences Technology, Ijero Ekiti, Ekiti State, Southwestern Nigeria, with the aim of determining its groundwater potential. The qualitative interpretation of VLF – EM results identified areas of hydro-geologic importance and aid in the selection of specific points for VES. Thirty VES were carried out across the area using the Schlumberger electrode array configuration, with half-current electrode separation (AB/2) varying from 1 m to 65 m. The data acquired were interpreted qualitatively and quantitatively and were presented as table, maps, chart and section. The interpreted models revealed three to six geo-electric layers namely; topsoil, lateritic clay, weathered layer, fractured basement and the fresh basement. The weathered basement and the fractured basement are the potential aquiferous layers within the area. On the basis of the characteristics of geo-electric parameters the study area is zoned into good, intermediate and poor groundwater potential zones. However, the groundwater potential of the area is generally rated low.