Application of 1D and 2D Electrical Resistivity Methods to Investigate the Subsurface Properties of Egbeta, Edo State, Nigeria

Abstract

1D and 2D electrical resistivity methods were combined to investigate the subsurface properties of Egbeta community for minerals and groundwater potential. The Vertical electrical sounding (VES) and Electrical resistivity imaging (ERI) data were acquired with the aid of PASSI-16L-N Earth resistivity meter, using Schlumberger and Wenner array configuration respectively. The VES geoelectric sections were drawn using AutoCAD 2007 version after the data were interpreted with WINRESIST computational software. The 2D data acquired were interpreted using EARTH IMAGER software which helps to automatically obtain the 2D inversion model of the subsurface. The results from the VES survey six layers: sandy topsoil, lateritic clayey sand, sand stone, gravel/coarse sand and sand. The result of the ERI from the 2D inversion model divides the 2D image of the inversion model into three horizontal cross-sections, the first zone having resistivity range of 34.3 Ωm to 850 Ω, with depth range between 0 m to 15 m and lateral extent > 250 m. The middle zone has resistivity range between 600 Ωm to 8689 Ωm, with depth range between 15 m to 86 m. The lateral extent of this region is over 280 m. The third region which is in the deepest part of the subsurface has resistivity range between 580 Ωm to 1200 Ωm and lateral extent > 200 m.

Keywords: Electrical, Resistivity, Subsurface Properties, Zones, Aquifer, Minerals