OSENI RESAQ ABU

This study examined the use of Electrical Resistivity Tomography (ERT) to investigate the subsurface lithology in Ugbogiobo, Ovia North East Local Government Area of Edo State. The research aimed to determine the variation in subsurface materials and identify geological structures that may influence groundwater potential, engineering suitability, and environmental conditions in the study area. The study adopted a geophysical survey approach using the ERT method, where resistivity measurements were taken along selected profiles to generate two-dimensional subsurface images. Data obtained were processed and interpreted using standard inversion software to produce resistivity models that reveal variations in lithological units. The results showed distinct subsurface layers characterized by varying resistivity values, indicating differences in soil composition, moisture content, and degree of weathering. The near-surface layer was generally composed of lateritic and sandy materials with relatively high resistivity values, while deeper zones exhibited lower resistivity indicative of clayey formations and possible water-bearing zones. The study also identified potential fracture zones and areas of structural weakness, which are important for groundwater accumulation and civil engineering planning. The study concludes that Electrical Resistivity Tomography is an effective non-invasive geophysical tool for subsurface investigation in Ugbogiobo. It provides reliable information on lithological variations and groundwater potential. The research recommends the integration of ERT surveys in site investigation studies before construction and borehole drilling to improve decision-making, reduce failure rates, and enhance sustainable groundwater development in the area.

2-D survey of a part of Ugbogiobo community and its environs has been carried out successfully and this research has helped in providing information about the subsurface of the study area. This information is of utmost importance as it gives the necessary constituents of the profile of the study area. The subsurface of a study area is related to various geological parameters such as mineral and fluid content, porosity and degree of water saturation in the rock. Major resistivity structures were delineated in both profile which is seen to be generally characterized by moderate resistivity values, at the top layers we can inferred from the low resistivity that is characterize by Clayey and Alluvium soil having a resistivity range between 200 Ωm– 800 Ωm profile 7 and 8 respectively. The major mineral occurrence in profile 7 and 8 are majorly compose of sedimentary Rocks ranging from Limestone, Shale and Sandstone with a resistivity range for Limestone between 2000 Ωm– 3000 Ωm, Shale with a resistivity range 3200 Ωm– 4000 Ωm Sandstone between resistivity range 4000 Ωm– 5000 Ωm, it will be noticed from the profiled line that all inferred mineral types fall between a depth of 2 m to 39 m. which form the lithological mineral occurrence of the both profiles. The development of two dimensional inversion resistivity algorithms has aided the processing and interpretation of complex data. Due to the inferred rock types and mineral occurences (Alluvium, Clayey soil, limestone, sandstone, and clay) gotten from the lithological interpretation of the 2-D data inversion, it can be concluded that the lithology of the study area is good for engineering purpose and construction work.