Application of surface and subsurface anomaly linkage in geothermal resource evaluation: A case study of the Corbetti geothermal prospect, main Ethiopian rift

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The Corbetti geothermal prospect (CGP) represents a rapidly uplifting, dynamically deforming volcanic region and a seismically active zone within the central Main Ethiopian Rift. Beyond its fundamental role in understanding rift evolution, the Corbetti caldera complex hosts multiple active volcanoes that serve as potential heat sources for generating geothermal energy. While the influence of tectonic and volcanological structures on the occurrence of these geothermal resources is well known, understanding how subsurface heterogeneous structures govern the availability of geothermal fluid reservoirs remains a challenge An integrated analysis of thermal infrared remote sensing data and gravity and magnetic within the CGP was used to identify anomalous temperature areas, delineate subsurface geological structures, and investigate their connection with geothermal resources. The highest concentrations of high surface temperature regions were observed at the Shala volcanic complex and north of the Corbetti caldera complex, while the lowest surface temperatures were identified in the southern and southeastern parts of the Wondo Genet. The analysis of the gravity and magnetic anomaly maps, along with 2D gravity/magnetic models and a 3D conceptual model, provided insights into subsurface magma plumbing systems and to the presence of deep-seated geothermal heat sources within the CGP. The groundwater outflow from Lake Awasa towards Lake Shala interacts with the intrusive heat under the Corbetti caldera complex at the middle of the two lakes which enhances the occurrence of geothermal resources. The existence of faults and fractures determined from geological mapping and gravity and magnetic derivative analyzes likely facilitate the migration of melt from deep intrusions to shallow magma reservoirs, acting as conduits for groundwater and ultimately manifesting as thermal anomalies at the surface beneath the Corbetti caldera and southern shore of Lake Shala.