Volumetric Analysis of Predominant Subsurface Earth Materials and 3D Tomography for Predicting Soil Erodibility in Abotse Quarters, Auchi, Etsako West LGA, Edo State, Nigeria

Abstract

Geophysical probing of the subsurface with the use of 3D electrical resistivity tomography (ERT) was done in Abotse quarters, Auchi,  Etsako West LGA of Edo State. It was to ascertain the level of soil erodibility having in mind to curb the potential immense danger  targeted at our natural land with its associated infrastructure. Four layers from the horizontal depth slices with the following depths: 0 to 3.5 m, 3.5 to 7.52 m, 7.52 to 12.2 m and 12.2 to 17.5 m. Their corresponding resistivity values rose from 1485 to 113614 Ωm, 624 to 113614  Ωm, 262 to 113614 Ωm and 262 to 113614 Ωm with respect to every layer. Resistivity distribution was from 358 to 217741 Ωm and a drill  depth of 15.4 m was achieved. This study demonstrated that soils with an ER well above 50 Ωm have a high percentage of being regarded  as highly erodible. The findings suggest that ERT can be employed to immediately identify and prioritize areas where soils near  the surface are vulnerable to erosion, thereby necessitating more detailed investigations. Sandstone and lateritic sand with a  volume of 536,689 m³ and 78,393 m³ respectively are the predominant subsurface earth materials found in Abotse quarters. These large  volumes of predominant earth materials explain the persistence of erosion in the area of study.