GEOPHYSICAL INVESTIGATION OF SUBSOIL CORROSIVITY WITHIN UNIVERSITY OF CROSS RIVER STATE, CALABAR, CALABAR SOUTHERN NIGERIA

Abstract

Assessment of subsoil corrosivity was conducted within the University of Cross River State, Calabar, Calabar Campus, Southern Nigeria. The study employed electrical resistivity methods. The results from vertical electrical sounding revealed that the topsoil of VES₁ and VES₃ was slightly corrosive at depths of 2.20m and 0.70m while that of VES₂ and VES₄ were practically non–corrosive at depths 0.60m and 1.00m. The electrical resistivity tomography across the VES₂ and VES₄ showed a low resistivity at horizontal distances between 5.0m and 10.0m at a depth of 3.75m, indicating very strongly corrosive. Other areas of the profile with resistivity from 19.0 Ώm to 38.0 Ώm at a depth of between 6.38m and 19.8m indicate moderately corrosive and 75.0 Ώm which is slightly corrosive.  A resistivity of 148.0Ώm to >580Ώm at the top layer indicates practically non–corrosive at depths 6.38m and 19.4m. Hence, metallic pipes should be buried at depth 3.0m.