Page 1 of 6 Relevance of Electrical Resistivity Geophysical Method in Engineering Site Characterization in A Basement Complex Terrain Adiat KAN* Federal University of Technology, Akure, Nigeria Introduction Conducting a geotechnical characterization of a site involves: completing document reviews, soil sampling, in-situ testing, and/or laboratory analysis of samples from the area under characterization (Day, 2006). Materials of interest to geotechnical engineer in site characterization are the soil and rock formations. These materials, apart from not being manufactured, do not possess a consistent and homogeneous set of properties. In addition to these, location and geologic histories also play significant role in the uniqueness and peculiarity of these materials. Consequently, it is important to properly and adequately characterize a site before design and construction are initiated. Site characterization can be broadly described as the defining of existing soil properties at a given site [1]. This is because understanding the properties of the subsurface allows the geotechnical engineer to predict soil behavior under a myriad of scenarios. Furthermore, it will also assist in making informed recommendations regarding appropriate foundation types, means for mitigating or preparing existing soil conditions for construction, and forecasting potential issues during construction. Although various advancements in the field of in-situ testing have improved the quality of collected soils data; however, known conditions are still point specific and thus limited to a confined area; consequently, data must be extrapolated amongst an entire soil mass for design purposes. This extrapolation often leads to making some assumptions about earth conditions. Such assumptions can at times lead to structural failure which can culminate to loosing of lives and properties. This is because undetected, but possibly existing natural and/or man-made anomalies can nullify constant earth assumptions often used during the analysis and evaluation of geotechnical data. Encountering anomalous conditions during site development and construction can lead to truncation, interruptions or complete abandonment of the entire project schedule. It can also lead to additional labor and material costs, and capable of posing *Corresponding author: Adiat KAN, Federal University of Technology, Akure, Nigeria. Received Date: February 05, 2019 Published Date: March 26, 2019 ISSN: 2641-2039 DOI: 10.33552/GJES.2019.02.000526 Global Journal of Engineering Sciences Research Article Copyright © All rights are reserved by Adiat KAN This work is licensed under Creative Commons Attribution 4.0 License GJES.MS.ID.000526. Abstract In this study, relevance of electrical resistivity geophysical technique in engineering site characterization had been demonstrated. The aim of the study was to establish the capability of the technique to unravel subsurface conditions through quantitative assessment/evaluation of subsurface geoelectric parameters. In order to achieve the objectives of the study, twenty (20) VES were acquired using R-50 Resistivity meter. The results obtained from both the qualitative and quantitative interpretations of the VES data were utilized in preparing geoelectric sections and some important layers parameters maps. The dominant curve types obtained suggest that the study area is largely characterized by the presence of highly weathered/fractured basement with evident of saturation. Three geologic layers were generally delineated, and these were top soil, weathered/fractured basement and the basement. The top soil was observed to be of thin thickness indicating that the foot of the foundation might inevitably be extended to the layer underlain the top soil. Series of linear features such as basement depressions and ridges, fracture, geologic contacts etc. capable of aggravating foundation failure were observed in some parts of the area. The study has consequently established the efficacy of electrical resistivity as a geophysical tool that can complement conventional geotechnical studies in engineering site characterization. Keywords: Foundation failure; Geotechnical; Subsurface competence; Site characterization