Integrated geophysical methods have been used to investigate the competency of the subsoil. The geophysical surveys conducted involve very low-frequency electromagnetic (VLF-EM) and electrical resistivity (ER) methods (dipole-dipole). ABEM Wadi and Ohmega resistivity meter were used to acquire VLF-EM and ER data, respectively, along two traverses. Station interval of 5 m was used for the VLF-EM survey, while inter-electrode spacing for dipole–dipole was 10 m; the inter-dipole expansion factor (n) ranged from 1 to 5. KHFFILT software was used to generate VLF-EM profiles and pseudosection, while DIPRO software was used for ER. Results from the ER method revealed the pattern of resistivity variations within the study area. The low resistivity values (11–25 Ohm-m) observed at the southern part of the study area could be attributed to changes in clay contents and degree of weathering in the subsurface. The results from the VLF-EM investigation revealed the presence of near-surface linear geologic structures of varying lengths, depths and attitudes, which suggest probable conductive zones that are inimical to the foundation of the road subgrade.
If the inline PDF is not rendering correctly, you can download the PDF file here.
 Adiat K.A.N Adelusi A.O. Ayuk M.A. (2009). Relevance of Geophysics in Road Failures investigation in a typical basement complex of southwestern Nigeria. Pacific Journal of Science and Technology 5(1): 528–539.
 Akintorinwa O.J. Ojo J.S. Olorunfemi M.O. (2010). Geophysical investigation of pavement failure in a basement complex terrain of south-western Nigeria. Pacific journal of science and technology 11(2): 649–663.
 Momoh L.O. Akintorinwa O.J. Olorunfemi M.O. (2008). Geophysical Investigation of Highway Failure. A case Study from the Basement Complex Terrain of South-western Nigeria. Journal of Applied Sciences Research 4(6): 637–648.
 Omujakporue O.G (2012). Geophysical Investigation of the Causes of Highway Failures in Niger Delta Sedimentary Basin (A Case Study of the Eastern Part of East-West Road) Nigeria. Scientia Africana 11(1): 143–152.
 Oni A.G. Olorunfemi M.O. (2016). Integrated Geophysical Investigation of the Igbara-Oke-Igbara-odo Road Pavement Failure in Ondo/Ekiti State Southwestern Nigeria. Ife Journal of Science 18(1): 119–131.
 Nwokoma E.U. Chukwu G.U. Amos-Uhegbu C. (2015). Geoelectrical Investigation of Soils as Foundation Materials in Umudike Area Southeastern Nigeria. Physical Science International Journal 6(2): 82–95.
 Adeleye A.O. (2005). Geotechnical Investigation of Subgrade Soil along Sections of Ibadan-Ife Highway. Unpublished M.Sc. Project Obafemi Awolowo University; 181Pp.
 Farinde M.A. Oni S.O. (2015). Geophysical and Geotechnical Characterization of Newly Constructed Abadina-Ajibade Road University of Ibadan Ibadan. Journal of Multidisciplinary Engineering Science and Technology 2(1): 363–378.
 Mesida E.A (1987). The Relationship between the Geology and the Lateritic Engineering Soils in the Northern Environs of Akure Nigeria. Bulletin of the International Association of Engineering Geology 35: 65–69.
 Olorunfemi M.O. Ojo J.S. Sonuga F.A. Ajayi O. Oladapo M.I (2000). Geoelectric and Electromagnetic Investigation of the field Koza and Nassarawa Earth Dams around Katsina Northern Nigeria. Journal of Geology and Mining Research 36(1): 51–65.
 Olorunfemi M.O. Ojo J.S. Idomigie A.I. Oyetoran W.E (2005). Geophysical Investigation of Structural Failure at a Factory Site in Asaba Area Southern Nigeria. Journal of Geology and Mining Research 41(1): 111–121.
 Osinowo O.O. Akanji A.O. Akinwosin A. (2011). Integrated Geophysical and Geotechnical Investigation of the Failed Portion of a Road in Basement Complex Terrain southwestern Nigeria. RMZ-Material and Geoenvironment 58(2): 143–162.
 Oladunjoye M.A. Salami A.J. Aizebeokhai A.P. Sanuade O.A. and Kaka S.I. (2017). Preliminary geotechnical characterization of a site in Southwest Nigeria using integrated electrical and seismic methods. Journal Geological Society of India 89: 209–215.
 Oyeyemi K.D. Aizebeokhai A.P. Adagunodo T.A. Olofinade O.M. Sanuade O.A Olaojo A.A. (2017). Subsoil characterization using geoelectrical and geotechnical investigations: Implications for foundation studies. International Journal of Civil Engineering and Technology 8(10): 302–314.
 Obaje N.G (2009). Geology and Mineral Resources of Nigeria. Heidelberg: Springer 221p.
 Owoyemi F.B. (1996). A geologic-Geophysical Investigation of Rain-induced erosional features in Akure Metropolis. Unpublished M.Tech Thesis Federal University of Technology Akure pp. 11–18.
 DIPRO (2000). DIPRO for Windows Version 4.0 Processing and Interpretation Software for Diole-Dipole Electrical Resistivity Data. KIGAM Daejon South Korea.
 Bayewu O.O. Mosuro G.O. Oloruntola M.O. Osho A.C. (2012). The Resistivity and Electromagnetic Survey for Groundwater Evaluation in Part of Ago-Iwoye Southwestern Nigeria. International Journal of Advances in Science and Technology 5(1): 77–99.