Fisseha, Shimeles (PhD)Issa, Yayso2020-09-212023-11-092020-09-212023-11-092020-07-07http://10.90.10.223:4000/handle/123456789/22386A geophysical survey involving the electrical resistivity method utilizing the Vertical Electrical Sounding (VES) and Electrical Resistivity Imaging Techniques were conducted around Ududaytu area in the Tandaho graben of Afar, North eastern Ethiopia with the aim to characterize the suitability of the Ududaytu area for building foundation to support engineering structures. A total of 16 VES stations and four Electrical Resistivity Imaging profiles were conducted. The VES stations were measured using Schlumberger Configuration with AB/2 varying from 150 m to 220 m. Whereas Electrical Resistivity Imaging profiles were acquired using Wenner-Schlumberger configuration with electrode spacing of 5m. Four to five main geoelectric sequences were delineated within the study area; these include the topsoil, the upper clay, fine to coarse sand and the bottom clayey sandy /clayey silty layer. A major NNW - SSE discontinuity (fracture zone) was identified. Therefore, this study has showed the usefulness of geophysical methods to delineate the lateral and vertical variations of the subsurface layers and its implication in engineering structures. From geotechnical point of view, the geoelectrical results has shown that the study area is underlain thick sequence of sediments that are not competent enough to bear loads from heavy engineering structures. The study area being within tectonically active region, with peak ground acceleration (PGA, g > 0.3), erecting multistory structures over such relatively weak formation require proper engineering measures during the design and construction stage. Specially, since the amplification potential of such soft formations in the site-soils, could be ominously larger, the design should address the entire relevant factor towards proper mitigation.enElectrical MethodsVertical Electrical SoundingElectrical Resistivity ImagingBuilding FoundationThesis