Evaluation of Factors Responsible for Landslide in Haro Village and its Surrounding, North Shoa, Centeral Ethiopia
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Date
2007-07
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Addis Ababa Universty
Abstract
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.
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Haro Village