Lewi, Elias (PhD)Assefa, Yigrem2018-07-122023-11-092018-07-122023-11-092007-03http://10.90.10.223:4000/handle/123456789/8133In this thesis work three integrated geophysical investigations namely; gravity magnetic and electrical resistivity sounding have been carried out over Gemeto thermal springs. The area is situated in the central sector of the main Ethiopian rift at a close proximity to the SE of Awassa town. The study aims at investigating all the necessary geothermal characteristics in the area based on the thermal manifestations. To achieve the objectives of the research, the required data for each of the geophysical method applied in this study are collected, processed, and interpreted .Based on the results obtained from the data analyzed using standard softwares; interpretations and concluding remarks are also given. Results from gravity survey indicate two interesting features; the first one is the heat source for the Gemeto thermal springs has been characterized. Small area near the springs has shown uniquely the lowest negative Bouguer anomaly values. In principle, lowest Bouguer anomaly values are indicatives of either high cliffs or high density materials. Our study area is inside the Awassa caldera where high density volcanic rocks are common with the lowest topography in the area. Therefore, the lowest Bouguer anomaly values in the area are interpreted as densities of rocks in the area are lowered due to thermal expansion. The second one is the regional structural trend extending NE-SW that is clearly shown on the Bouguer and regional anomaly map. Interpreted as an extension and integral structure of the eastern escarpment of the rift. From the magnetic anomaly map, the area proposed by the gravity method to be the possible heat is also characterized by the lowest total magnetic field response. This is interpreted as rock units in that area are forced to lose their elements with magnetic properties due to high temperature. The method has also shown different major shallow fault structures mainly lying in NNE-SSW and N-S directions. The 2-D magnetic models prepared along two profiles also confirm these results. Results from vertical electrical soundings along one profile show that the first top layer up to 10m has resistivity values of 2-24Wm which is indicative of alluvium soil deposits in the area and the second layer of thickness between 20 to 60m, the resistivity value varies from 12-37Wm which is interpreted as coarse clay materials. In both geoelectric and pseudosection diagram shallow structure between VES3 and VES4 is observed which is interpreted as one of the major shallow structures identified by magnetic method. These shallow structures identified by magnetic and electrical methods are possible structures that recharge the area. Based on the joint analysis of these geophysical methods and thermal manifestation, the area has the potential for small scale development such as center for recreation and thermal therapy. Besides, additional geophysical methods are proposed to further reinforce the outcome of the study.enGemeto thermal springsThesis