Hydrogeophysical Investigation in Nsukka Area Southeastern, Nigeria

ABSTRACT Resistivity surveys were carried out at seven stations within the university of Nigeria, Nsukka and its environs. The objective was to determine areas suitable for the drilling of boreholes for groudhvater. The results generated from this survey were interpreted in terms of the number of subsurface layers, usurer thickness, depth to uquifer and, probable lithology$orrnations. However, lithologic interpretations were carried out using exist ring borehole data from the area. A BEM Terrrrrnerer SAS 300C instrument was used in obtaining the resistivity data Partial manual curve matching technique~~ was initially employed in interpreting the data and therefore n comparer iteruted approach was used to arrive at the final result. The Schlumberger electrode configuration WLIS employed. Results show that the depth to water table in the study urea fall within the lower ports of layer 5, at a depth of about 11 0. Om. Thicknesses oj' the top soil vary between 0.8m and 1.2m, witli their resistivity’s ranging between 50Ch und I l20fi1. The number of layers encountered is 6 and 7. Geological interpretation based on available borehole lithology of the area shows that the subsurface comprises lateritic sandstone in the Nsukka Formation and coarse - medium grained sandstones in the .4jali Formation.