IMAGING GRAVITY MOHO WITH PROBABILISTIC COMPUTATION OF DETERMINISTIC VARIABLES: APPLICATION TO WESTERN PLATEAU OF ETHIOPIA

Plate Tectonics is one of the greatest scientific achievements that attempts to describe the origin and evolution of the Earth’s plates in the most systematic manner. However, like all scientific blueprints, Plate Tectonics must be concretized. It must be better understood, tested, and modified by constantly making novel observations. This constitutes defining the lithospheric architecture of various geodynamic settings that are overlain by tectonically sculpted geomorphological features. To do this, effective and cheaper methods are desired and needed. Our improved gravity method would significantly help in this endeavor as it uses a robust geo-statistical approach to model the petrological Moho topography by using freely accessible satellite gravity data, WGM-2012. The approach bases the work of Gomez-Ortiz and Agarwal (2005) algorithm and extends it to an ensemble analysis in which all the converging parameters as well as the density contrast and the average depths are simulated with several scenarios to achieve a mean Moho topography that best represents the sub-crustal geology as well as the overlying tectonically driven geomorphologic features. This method is tested to investigate the sub-crustal geometry of the Western Plateau of Ethiopia and its surroundings. The results are further verified by a gravity and magnetic joint forward models. The non-zero free air gravity of the Western Plateau of Ethiopia, its topography, and the sub-crustal structure, suggest that the sub-continental lithospheric mantle root beneath the Western Plateau of Ethiopia is not fully compensated and is possibly thermally supported. This work shows the technique employed is robust and effective and can be used to investigate different types of geodynamic settings by using freely accessible satellite gravity data such as WGM-2012.