Reuben Phiri^1,, Wallace Mukupa¹, Foster Lubilo¹, Alick R. Mwanza¹

The economic growth that Zambia seeks to attain calls for alternative sources of energy besides hydroelectricity which has proved inadequate due in part to climate change. One such form of alternative energy is geothermal energy. Various research has been undertaken on the feasible way of harnessing geothermal energy using different methods such as thermal, electrical, magnetic and seismic methods. But exploring for potential sites was still a challenge. One way round this challenge was to devise a method that first identifies potential geothermal sites instead of relying on trial and error scenarios. This study used gravity data obtained by the European Space Agency (ESA) through Global Monitoring for Environment and Security (GMES) project. This data was used to calculate gravity disturbances of the earth’s crust in order to understanding density variations in the subsurface geology. This study therefore, used the density variations in the subsurface geology to map potential geothermal sites at a scale which makes it feasible and economical for geophysicists and geologists to have a starting point in exploring for geothermal energy. In so doing, this study devised an economical method of mapping potential geothermal sites using the freely available gravity data by assessing the accuracy of the gravity data using mean sea level elevations, mapping gravity disturbances and relating them to thermal imagery, geological and land use maps to produce potential geothermal site maps at feasible and economical scale. This study found that the use of hot springs as an indication of potential geothermal sites was not accurate and definitely not a right basis for investigating geothermal resources. Potential geothermal sites were found to lie within the rift valley where temperature are high and where the earth’s crust density is low in addition to faulting.

geothermal potential sites, gravimetric data, geodesy, gravity disturbance, thermal imagery