THE USE OF 2-D ELECTRICAL RESISTIVITY IMAGING TO CLASSIFY THE EARTH’S SUBSURFACE IN OFUNMWEGBE COMMUNITY AREA, BENIN-CITY, NIGERIA.

ABSTRACT

Classification of the earth’s subsurface in Ofunmwegbe Community area was done using 2-Dimentional electrical resistivity imaging to understudy the lithology of the area. This project is to provide lithological information to engineers for excavation purposes and other construction work owing to the gradual development in the area. It also helps in understanding the hydrological structure of the area. A total horizontal length of 60m was covered with a depth of about 12.4m, using a minimum electrode spacing of 5m. With the aid of the Petrozenith Terrameter (PZ-03) and using the dipole-dipole array method, data was obtained which was later interpreted using the RES2DINV software. Four traverse data were obtained and from the 2-D image the lithology of the study area shows that it is rich in various rock types like shale, and sandstone. Resistivity range is between 93.80 – 5753267.00Ωm at a maximum depth of about 12.4m, from the top layer, alluvium and laterite soil were observed. At a depth of about 12.4m groundwater was suspected.

Hence, the study area may show good prospect for groundwater by virtue of probable thick aquifer layer.