INTEGRATION OF MULTICHANNEL ANALYSIS OF SURFACE WAVES (MASW) AND ELECTRICAL RESISTIVITY TOMOGRAPHY (ERT) FOR THE SUBSURFACE CHARACTERIZATION OF UGBOGIOBO, OVIA NORTH EAST, EDO STATE, NIGERIA

ABSTRACT

Multichannel Analysis of Surface Waves (MASW) was integrated with Electrical Resistivity Tomography as an investigative tool in determining the shear wave velocity and resistivity values of a specific location at Ugbogiobo community, Ovia North East Local Government Area of Edo State, Nigeria. This investigation was targeted at having a comprehensive idea of subsurface lithology of the area. Four (4) traverse lines were profiled with electrode spacing of 10 m amounting to a horizontal length of 300 m using the Wenner Array configuration as a survey technique in the ERT aspect. The 2-D Electrical Resistivity data was processed using RES2DINV software. From the results obtained it is evident that over a depth of between 5 m to 56 m for all the profiled lines there is composition of Alluvium and clayey soil at the top surface with low resistivity values at a depth below 10 m with resistivity values ranging between 50 Ωm–800 Ωm. While Shale, Slate and Sandstone occurred at a depth of between 13 m to 25 m with resistivity values ranging between 1000 Ωm–3000 Ωm. Above a depth of 30 m revealed limestone and thick clay with resistivity values raging between 5000 Ωm– 30000 Ωm. And with reference to the Seismic data recorded and processed using SeisImager2D refraction software we find that the elastic parameters of the soil correlates well with the delineated stratigraphy.