Bayewu, OMoroof, OOGaniyu, MOFolorunso, IOKolawole, AU2023-01-052023-01-052014https://ccsenet.org/journal/index.php/jgg/article/view/41102https://uilspace.unilorin.edu.ng/handle/20.500.12484/8133This study was carried out to determine the anisotropic properties of parts of the Southwestern Basement Complex of Nigeria in Ijebu Igbo, which is underlain by migmatite gneiss and older granites. The surface water level (SWL) of 107 hand-dug wells were measured to determine the groundwater flow direction of the area. Thirty Azimuthal Resistivity Survey (ARS) were investigated along four azimuths; 0°, 45°, 90°, and 135° to determine the electrical anisotropy, the trend of fractures and their behavioural pattern with depth. The quantitative interpretation of the Radial Vertical Electrical Sounding (RVES) curves involved the use of partial curve matching, and computer iteration using WINRESIST program. The results of the wells measurement showed that the major directions of groundwater flow pattern of the study area are N-S and E-W while the NE-SW or NW-SE are less prominent. Geo-electric interpretation of the RVES data revealed the area to be underlain by three geo-electric layers; Top soil, (160Ωm - 1454Ωm), lateritic Horizon clayey/sandy clay horizon, (22Ωm - 160Ωm), and weathered/fresh Basement (421Ωm - 3122Ωm) with depth to fracture systems ranging from 6.3-54m. The reflection coefficient observed ranges from 0.6-0.98. The direction of electrical anisotropy was derived from the polar plot and lies predominantly at NW-SE and E-W, N-S while the NE-SW is less prominent. Coefficient of anisotropy ranges between 1.09 and 1.36 with a mean of 1.2. The apparent anisotropic graphs show the behavioral pattern of the fracture with depth and reveal that the predominant fractures in the area are closing with depth. The orientation of geologic structures from the study area showed an E-W, and NW-SE direction and this corresponds to the directions of the electrical anisotropic polygons. The fractures are known to be complex and in turn interconnected, hence a fracture controlled flow. Areas with low bedrock resistivity, thick overburden, presence of two interconnected anisotropy polygon directions and high co-efficient of anisotropy indicate intense fracturing, thus, a potential sites for the drilling of water boreholeenresistivity anisotropy, groundwater flow direction, anisotropy polygon, coefficient of anisotropy, fracture directionArticle