GEOPHYSICAL CHARACTERIZATION OF SUBSURFACE CONDITIONS FOR ENGINEERING DESIGN: A CASE STUDY OF A PROPOSED SITE AT OVIA NORTH EAST LOCAL GOVERNMENT AREA, BENIN CITY.

ABSTRACT
This study employed electrical resistivity (ER) geophysical survey
techniques, including Vertical Electrical Sounding (VES) and 2-Dimensional (2-D) profiling, to characterize the subsurface structure of a proposed construction site within Ovia North East Local Government Area. Utilizing a PASI resistivity meter, the survey identified several geoelectric layers: a topsoil layer of sand with resistivity values between 126 Ωm and 470 Ωm and thicknesses of 0.9 m to 1.0 m, a deep sand layer up to 41.7 m
with resistivity values from 159 Ωm to 748 Ωm, and a clayey sand/sandy clay layer extending to 50.3 m with resistivity values of 54 Ωm to 72 Ωm. 

Additionally, a low resistivity zone indicative of clay/sandy clay was
detected at approximately 17 m depth in the 2-D profile. The investigation revealed a homogeneously structured subsurface, absent of expanding peat or clay, with layers capable of supporting structural loads for multi-story construction. The findings highlight the potential of the identified sand layer as a competent foundation for engineering structures due to its significant
thickness and favorable resistivity values