Integrated Geophysical Approaches for Geothermal Potential Assessment of the Arto Hot Spring, Alaba Woreda, Southern Ethiopia.
No Thumbnail Available
Date
2020-06-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In this research, integrated geophysical survey using electrical and magnetic methods was conducted to assess the geothermal energy potential of the Arto hot spring, Alaba special zone, southern Ethiopia. The study area is located 240km southward from Addis Ababa, and accessible through the Ziwaw - Shasemene- Alaba asphalt road. In Ethiopia, there exist some geothermal energy prospects, which have proved to have significant geothermal potential. Arto hot spring is one of the geothermal sites, about which prospection had not been carried out, yet. The main objective of the research is assessing the geothermal potential of the area, Arto hot spring, by employing geophysical methods, apart from describing geological features (both structures & lithology), and geothermal manifestations, such as hot springs, mud pool and swamps.
Totally, the geophysical data has been gathered at -nine vertical electrical sounding (VES) data points using Schlumberger electrode array with a maximum half electrode spacing, AB/2=750m in three traverse lines; and 311magnetic data points with station spacing 10m. The analysis result of the resistivity data was presented in the form of interpreted VES curves, pseudo depth section, stacked section, and geoelectric section maps. Whereas the magnetic data was presented in terms of total magnetic, residual magnetic anomaly, analytical signal, tilt derivative, Euler deconvolution magnetic and magnetic profile maps.
From the electrical resistivity analysis, the low resistivity, which is less than 10Ω-m, and observed on the pseudo depth & geoelectric sections along Line-1, depicts that the geothermal manifestations. The result indicates that the low resistivity is due to the combined effects of the lithology of the subsurface rocks, the thermal heat, and the high salinity of the subsurface fluid. In the analysis, low magnetic anomaly coincides with low electrical resistivity results, showing that there exists anomalous subsurface heat. The magnetic anomaly map depicts the subsurface geological structures, trending NE-SW and NW-SE. The dominant structures, observed in the study area is correspondingly aligned with the general trend of the Main Ethiopian Rift (i.e., NE - SW). The main thermal manifestations in the study area are situated parallel with the Main Ethiopian Rift structure.
According to the result acquired from the geophysical methods and the thermal manifestations, the area is proved to be potential from geothermal energy resource point of view. However, more detailed-geophysical surveys should be conducted.
Description
Keywords
Integrated Geophysical Approaches, Geothermal Potential, Assessment of the Arto Hot Spring, Alaba Woreda, Southern Ethiopia