Vertical Electrical Sounding was carried out using ABEM SAS 1000 Terrameter and Schlumberger electrode configuration was employed for reasons of logistics of manpower and its characteristic deep penetrations into the subsurface [4].
The Schlumberger array requires that four steel electrodes are arranged and pinned collinearly into
the earth with the current electrodes spacing much greater than the potential electrodes and ensuring that AB/2 ≥ 5MN/2
where “AB” is current electrodes separation and “MN” is potential electrodes separation (Fig.2). This implies that
for MN = a, AB = na+a from which their values on table 1 were generated and approximated for convenience. The
electrodes were connected appropriately to their respective terminals on the terrameter through cables and
hammered to make good contact with the earth.