Interpretation of high-resolution aeromagnetic data to delineate buried faults in Ijebu Ode, Southwestern Nigeria

Abstract

Faults can be categorized as fractures or discontinuities in rocks where there is a displacement caused by movements of rock masses within the Earth’s crust due to the forces of plate tectonics. The rapid energy release associated with movement along active fault lines is responsible for most earthquakes. Faults can also experience slow displacement, known as aseismic creep. This research aims to identify subsurface structures to ensure that infrastructure like buildings, roads, railways, and power plants are not built on fault lines. In this research, methods such as Horizontal Gradient, Analytic Signal, and Euler Deconvolution were utilized on aeromagnetic data from Ijebu Ode in Southwestern Nigeria to identify subsurface structures. The findings of this study indicate the presence of deep tectonic fault features within the study area, with estimated depths ranging from approximately 200m to 2500m. The fault trends are more pronounced and generally trend in a NE–SW direction, suggesting the existence of a NNE–SSW oriented Ifewara–Zungeru fault zone, which is believed to be connected to the Atlantic fracture. An inferred geological map of the region, illustrating the fault lines, has been created, which can assist in the placement of infrastructure in the area as well as inform other geotechnical investigations.