Integrating VES and 2D ERI for near-surface characterization in a crystalline basement terrain

Abstract

Geoelectrical resistivity is one of the most common geophysical methods for near-surface characterization in many applications including hydrogeologic, environmental, engineering and mining investigations. This case study integrates vertical electrical sounding (VES) with two-dimensional (2D) electrical resistivity imaging (ERI) to characterize the near-surface in a crystalline basement terrain. The investigation was conducted in Ado-Ekiti, southwestern Nigeria to delineate the basement aquifer by characterizing the weathered and fractured zones of the basement rocks. The study is part of the preliminary assessment of groundwater potential in the area. Dipole-dipole array used for the 2D ERI proved to be effective in detecting weathered and fractured zones in crystalline basement rocks. The integration of VES with 2D ERI enhanced the reliability of the characterization.