Browsing by Author "Dimma Beto"

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    Evaluation of Factors Responsible for Landslide in Haro Village and its Surrounding, North Shoa, Centeral Ethiopia
    (Addis Ababa Universty, 2007-07) Dimma Beto; Raghuvanshi Tarun K. (PhD)
    As a consequence of frequent occurrences of landslides in Haro village and its surrounding, an investigation was undertaken to determine the factors responsible for the landslide in order to produce a landslide hazard Zonation map using the “Landslide Hazard Evaluation Factors (LHEF)” rating scheme as the main methodological tool. The geology of the area is mainly dominated by weathered and weak contact structural discontinuities of basalts, Limestone, Sandstone, gypsum and loose unconsolidated colluvial soils which are responsible for the instability of the slopes in the area. Six major inherent causative factors; Lithology, Structure, Slope morphometry, Relative relief, Land use land cover and Ground water conditions have been recognized for the purpose of generating a landslide hazard classification. For this purpose Landslide Hazard Evaluation Factor (LHEF) approach was employed. By applying the LHEF approach, these factors were analyzed facet wise based on the chosen categories. Each category is then given a corresponding rating based on the amount the factors contribute to the landslide activity. The ratings for each facet are summed up to give the Total Estimated Landslide Hazard Rating (TELHR). Finally, the landslide hazard map, from 54 facets, has been generated and five hazard zones have been identified as; very low (18%), low (15%), moderate (15%), high (41%) and very high (11%). From the very high and high hazard zones, the potential unstable slopes were identified and the Engineering properties of rocks and soils have been determined for classification purpose. As the slope instability posses danger to the villages are due to the geological structures, weak contact of rock beddings, poor drainages, less vegetation cover and loose unconsolidated colluvial soils, slope stability analyses and some possible methods of slope stabilization or remedial measures are necessary and have been described and suggested, and which should include; avoidance, surface and subsurface drainages improvements, constructing simple retaining structures and planting suitable trees.