Abera AlemuDenberu Besfat2026-07-282026-07-282022-06https://etd.aau.edu.et/handle/123456789/87113-D inversion of gravity and magnetic data is a powerful method for predicting geology beneath the surface through quantitative interpretation of the geophysical problem at hand. 3-D inversion of these two potential field methods increases the amount of information that can be extracted from the observed gravity and magnetic data. The ultimate goal of this MSc thesis is to implement 3-D inversions of airborne gravity and ground magnetic data. Accordingly, 3-D inversions of airborne gravity data collected with an 8 miles’ line interval for geodetic purposes (2006-2007) and magnetic data collected by the researcher along with existing magnetic data collected by previous MSc students of AAU have been used to study the crustal structure and determine the depth to Moho of the central part of the Main Ethiopian Rift (CMER) and adjacent plateaus. The analysis of the isostatic gravity anomaly and the 3-D gravity inversion had helped to compute and compile the depth to Moho map of the study area (CMER). Consequently, the crust beneath the rift floor was found to be thin and shallow (36-38km) while the crust beneath the South Western (SW) and South Eastern (SE) plateau regions is found to be thick and deep (38-44 km). Moreover, the 3-D gravity inversion and the analysis of isostatic anomalies had revealed that the crust beneath the rift floor is associated with positive density contrasts caused by magmatic intrusions intruding the crust over this region while the crust beneath the SW and SE plateau regions is associated with negative density contrasts indicating the crust beneath the plateau regions is embedded in to a high density mantle material and hence producing a negative density contrasts. The 3-D gravity and magnetic inversion in this MSc thesis work has finally produced 3-D subsurface density and susceptibility models of the study area (CMER). The principal inherent non-uniqueness problems faced with the inversion of gravity and magnetic data that exist based upon a static potential field were attempted to be constrained through incorporating as little information as obtained from previous studies and through by carefully designing a global objective function. This MSc thesis illustrates how the University of British Columbia Geophysical Inversion Facility (UBC–GIF) 3-D gravity and magnetic inversion codes can be applied to study crustal structure by establishing the necessary results. Henceforth, the 3-D inversion executed in this MSc thesis is the UBC-GIF’s inversion methodology which is 3-D regularized pixel-based algorithm proposed by LI and OLDENBURG (1996, 1998) where right rectangular prisms are used to define unknown density and susceptibility model parameters and the solution to the inverse problem is obtained by posing the inverse problem as a mathematical optimization process.en-US3-D Gravity Inversion3-D Magnetic InversionInversion CodesCentral Main Ethiopian Rift (Cmer)Density ModelSusceptibility ModelMoho DepthCrustal ThicknessIsostatic AnomalyMagmatic IntrusionsEthiopiaThesis