Qualitative and quantitative interpretations of high-resolution aeromagnetic data of Saki-East area, for basement and structural framework

Abstract

Earth tremor is a small earthquake or seismic event that occurs in seismically unstable region. However there have been little information about the earth tremor before year 1987, but events between 1990 and 2000 have triggered further researches. This research work is aimed at qualitatively and quantitatively interpret high resolution aeromagnetic data of Saki-East area to provide basement and structural framework of the study area. The aeromagnetic data of the study area consisting of Igboho data sheet 200 and Lechilaku sheet 221 were processed using Oasis Montaj software and interpreted for mapping basement and structural stability in the area. Enhancement process was further carried out on the data to generate residual aeromagnetic data used in determining the lineament orientations in the study area. 3D Euler deconvolution and Source Parameter Imaging (SPI) techniques were implored to determine basement depth of subsurface geological structures. The result shows positive correlation with geologic structures, low magnetic anomalies revealed subsurface deformation of crystalline basement rocks. 3D Euler solutions for SI = 1 shows large clusters depicting geological bodies associating with faults. The magnetic basement depth from 3D Euler and SPI shows over 90% dominance of shallow depth range of 3-600 m in the study area, this revealed that the dominant shallow depth of magnetic basement causes the faulting system of the study area becoming weak zones through which tremor occurs. The lineaments in the study areas are classified into major and minor lineaments, the major lineaments are prominent within the basement rocks and are possibly produced by the regional historic orogenic movement that affected Nigeria basement.