Abstract
Self-potential (SP) anomalies due to
electrokinetic and electric current density coupling were measured and analyzed
with the aim of determining associated electrokinetic (EK) coupling coefficient
induced by groundwater. The study deployed two non-polarizable Cu/CuSO4
electrodes and high impedance volt meter (Metrix MX-20) connected via reel of
insulated wire to measure the subsurface electrical potential anomalies in
parts of Southern Nigeria particularly Ikot Umiang Ede catchment plain, Etinan
LGA. SP measurements were performed along 4 profiles, where data were collected
at sample intervals of 25.0m using total station approach. This was
complemented by resistivity and geologic data obtained from VES and dug wells
respectively. The result showed strong agreement with the local hydrogeological
conditions of the environment. Low subsurface resistivity values were
delineated at depth consistent with the local hydrostatics. Also, the amplitude
of SP anomalies tends to be antisysmmetric across the survey areas, with places
of low resistivity values having weak magnitude potential anomalies. Similarly,
places with high resistivity values showed strong amplitude potential
anomalies. It was inferred that SP absolute potential anomaly provide
information on groundwater flux of an area.
Keywords: Subsurface, Self-Potential Anomalies, Electrokinetic, Hydrostatic
pressure, Groundwater flux.