Abstract

This work is about geoelectric investigation involving eight vertical electrical soundings carried out in Okon, Ofriyo, Idua, Ikot Udoma, Atabong, Mkpok, Afaha Eket and Ikot Eket in Eket local government area of Akwa Ibom State, southern Nigeria. The total current electrode spread varied from 300 m to 400 m and this depended on access roads, topography, human settlements and general infrastructure. The survey was aimed at investigating the resistivity of consolidated and unconsolidated formations of the study area and the depth of the Aquifer. The ABEM Terrameter, signal averaging system (SAS) 1000 was used in carrying out the soundings. Data obtained were interpreted using Hemkler computer program. This helped to produce various lithologic deductions for the sites surveyed. In general, there exists a common feature in the resistivity variation pattern of low-high-low in the area. The result shows a wide range of resistivity variation ranging from 0.70 to 27,885.60 Ωm. Four out of the eight sounding curves reflected the presence of four geoelectric layers, while the remaining four sounding curves reflected the presence of three geoelectric layers. The curve types reflected in this study are the K-type curve and the KH-type curve. Locations 4, 5 and 6 were productive (that is, water producing) with shallow aquifer depths of between 16.00 m and 30.40 m from the earth surface. Efforts should be made to check the quality of water in such a region, since aquifer in the region is located at shallow depths from the surface of the earth.

Key words: Vertical electrical sounding (VES), aquifer, resistivity, lithology, terrameter.