Effectiveness of the Ajayi - Makinde Two – Electrode array as a geoelectric prospecting method in depth – to - basement determination

Abstract

A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the conventional Schlumberger configuration was carried out in the Main Campus of Ahmadu Bello University (A.B.U.) Zaria with the aim of testing the reliability and effectiveness of the Ajayi-Makinde Two - Electrode array in depth - to - basement determinations. Interpretations of the two-electrode data and the Schlumberger data revealed that the geometry of the bedrock underlying the Main Campus is undulating. The depth – to - basement values for the Ajayi – Makinde Two – Electrode array ranges from 13.0 m in the central part of the study area to about 30.0 m around the southern end while that obtained from the Schlumberger configuration ranges from 11.0 m in the central part of the study area to about 29.0 m in the southern end. Results of the VES interpretation obtained in this work using the Ajayi - Makinde Two - Electrode array have compared very well with those obtained using the Schlumberger array at the same VES stations. The depth – to - basement values obtained in this work have also compared well with those obtained by previous researchers in the area. The Ajayi - Makinde Two - Electrode array is therefore reliable and effective and can be of use as a geoelectric prospecting method.

Keywords: Two–Electrode Array, Vertical Electrical Sounding, Depth–to–Basement and “Bulk Resistivity”