Abaya Geothermal Project, SNNPR, Ethiopia

Abstract

Reykjavík Geothermal (RG) is a geothermal development company that has been actively developing high-potential geothermal prospects worldwide for the past decade. Developing geothermal resources in Ethiopia has been an area of focus with three different geothermal projects underway: Corbetti, Tulu Moye, and Abaya. These projects are all located within the Main Ethiopian Rift, a prominent continental rifting zone part of the Great East African Rift System. The Abaya geothermal project is located on the western flank of the Southern Main Ethiopian Rift (SMER), where the plateau transitions into the rift floor, and is the furthest south of the RG geothermal projects in Ethiopia. The concession is directly above Lake Abaya, in what is known as the Southern Nations, Nationalities and Peoples’ Region (SNNPR) and is located approximately 270 km southwest from the country’s capital, Addis Ababa. The western half of the concession is cut across by a NNE-SSW trending fault swarm, known as the Wonji Fault Belt (WFB) which is thought to be the most active part of the MER. The concession is also the setting for two prominent graben structures, the Salewa-Dore graben, which is thought to host an array of scoria cones and active fissures, and the Chewkare graben. Surrounding and within the license area are various volcanic centers known as Doguna, Salewa-Dore, Hako, Chericha, and Donga. The Salewa-Dore and Hako felsic centers are thought to accommodate the most recent volcanic activity in the area, with several minor geothermal manifestations. Most geothermal surface manifestations are found on the Abaya fault, a large ignimbrite escarpment on the western part of the Chewkare graben. These manifestations are both thermal springs, ranging from moderate 35 °C to boiling as well as steaming ground/fumarolic activity, at close to 100 °C at 20 cm depth. Through numerous and extensive field campaigns, RG has been compiling GIS, geological, geochemical and geophysical data of the Abaya geothermal prospect in the aim of creating a scientific foundation to characterize the geothermal production potential of the area. Geochemical sampling of thermal manifestations, subsurface fault characterization, rock sampling, soil-gas analysis and an ongoing MT/TEM survey provide the data to create a conceptual model.