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Geological and gravimetric pattern of the Ethiopia
Kuznetsova, Alevtina ; Valenta, Jan (advisor) ; Martínek, Karel (referee)
From a geological point of view, Ethiopia is a unique country where active tectonics displays can be studied, in the context of extensive East African Rift System (EARS) evolution, where the Main Ethiopian Rift (MER) is a part. The Main Ethiopian Rift (MER) is typical continental rift structure spread between the African, Somali, and Arabian lithospheric plates stretching over 6,000 kilometres from Syria to central Mozambique. This study of the gravity pattern in Ethiopia reveals significant crustal thinning in the Main Ethiopian Rift and Northern Afar regions. In the southern Afar, the earth's crust has a slightly higher thickness and, moreover, probably contains a significant proportion of the continental crust. The understanding of crustal thinning in the context of active rifting is essential to predict future geodynamic events in that region, which is crucial for the sustainable life of a rapidly expanding population and the necessary construction of infrastructure. This work provides an analysis and re-interpretation of archival gravity data collected from land surface surveys and airborne gravity studies (archive of Geological Survey of Ethiopia) in conjunction with available geological and structural data to evaluate overall gravimetric pattern of Ethiopia and determine main geological...
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Geophysical and gravimetric pattern of Ethiopia, construction, and verification of a new gravity map of Ethiopia
Kuznetsova, Alevtina ; Valenta, Jan (advisor) ; Martínek, Karel (referee)
From a geological point of view, Ethiopia is a unique country where active tectonics displays can be studied, in the context of extensive East African Rift System (EARS) evolution, where the Main Ethiopian Rift (MER) is a part. The Main Ethiopian Rift (MER) is typical continental rift structure spread between the African, Somali, and Arabian lithospheric plates stretching over 6,000 kilometres from Syria to central Mozambique. This study of the gravity pattern in Ethiopia reveals significant crustal thinning in the Main Ethiopian Rift and Northern Afar regions. In the southern Afar, the earth's crust has a slightly higher thickness and, moreover, probably contains a significant proportion of the continental crust. The understanding of crustal thinning in the context of active rifting is essential to predict future geodynamic events in that region, which is crucial for the sustainable life of a rapidly expanding population and the necessary construction of infrastructure. This work provides an analysis and re-interpretation of archival gravity data collected from land surface surveys and airborne gravity studies (archive of Geological Survey of Ethiopia) in conjunction with available geological and structural data to evaluate overall gravimetric pattern of Ethiopia and determine main geological...
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Soil erosion risk analysis in Sidama Region, southern Ethiopia
Bizunhe, Getie Balkie ; Martínek, Karel (advisor) ; Hroch, Tomáš (referee)
Soil erosion is one of the most important environmental issues in Ethiopia. Studies on erosional processes and soil loss rates can provide insight into the landscape evolution, climate change, and human activities, as well as on land degradation risk. The soil coverage of the Sidama Region study area, Main Ethiopian Rift, is characterized by Major Reference Soil Groups as follows: Luvisols, Cambisols, Nitisols, Vertisols, Andosols, Fluvisols, Regosols, and Leptosols. Cambisols and Luvisols are more susceptible to erosion. Revised Universal Soil Loss Equation (RUSLE) is most developed and recently widely used algorithm which was used to map and estimate the spatial distribution of soil erosion rates in the study area. Two rainfall datasets and three soil structure datasets were tested for reliability. The resulting 6 RUSLE calculations were validated by field mapped polygons in selected areas. It showed that most reliable input datasets are new more complete rainfall data and soil structure data derived from field mapping and sample analysis. The most susceptible areas of soil loss are mapped and the mean soil loss rate in the study area is 28 t/ha/yr. The mean annual soil loss of Sidama study area is above the tolerable mean soil loss (18 t/ha/yr for Ethiopian highlands). The Revised Universal Soil Loss...
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