Geophysical Investigations for Groundwater Potential Assessment and Mapping Structures for Possible Connections between Lakes Langano and Shala, Main Ethiopian Rift

Assefa, Tagel (2008) Geophysical Investigations for Groundwater Potential Assessment and Mapping Structures for Possible Connections between Lakes Langano and Shala, Main Ethiopian Rift. Masters thesis, Addis Ababa University.

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Abstract

A low-lying narrow corridor covers the region between the two major lakes in the Main Ethiopian Rift-Lakes Langano and Shala. Owing to the differences in surface elevation between the two lakes and the fact that the region is affected by tectonism, the presence of possible subsurface rift structures and flow of fluids between the lakes has been postulated. Geophysical surveys, involving electrical resistivity, gravity and magnetic surveys have been carried out over the corridor to verify the presence of these structures. Three traverses, approximately selected to cross the area have been used for surveys. Nine VES points, 105 gravity and about 181 magnetic data have been collected and analyzed. The results are presented in the form of electrical pseudosections and geoelectricsections and also anomaly plots and modeled sections and interpreted to verify the presence of such features within the corridor. From the electrical survey data analysis it is seen that corridor between the two lakes is represented by an extensive low resistivity response region which is believed to result from a highly saturated subsurface horizon. The electrical survey has also mapped the presence of structures whose orientation makes them a candidate to act as fluid paths between the lakes. The gravity and magnetic data have been modeled together to depict the lateral and depth variations in density and magnetic susceptibility. These results also show the presence of structures that could act as paths for interchange of fluids between the two lakes.

Item Type:	Thesis (Masters)
Subjects:	Q Science > Q Science (General) Q Science > QC Physics Q Science > QE Geology
Divisions:	Africana
Depositing User:	Selom Ghislain
Date Deposited:	24 May 2018 12:43
Last Modified:	24 May 2018 12:43
URI:	http://thesisbank.jhia.ac.ke/id/eprint/4102

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