Landslide Hazard Zonation Around Ameya Town Konta Special Woreda South Nation Nationality People Region Ethiopia
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Date
2021-05-21
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Addis Ababa University
Abstract
In the present study, Landslide Hazard Zonation (LHZ) mapping around Konta special woreda Ameya town is carried out by applying Slope Stability Susceptibility Evaluation Parameter (SSEP) rating scheme. The main objective of the study was to prepare the LHZ map of the study area. A field survey was conducted to map the distribution of existing landslides and the factors that affect the landslide occurrences. Field measurements on structural discontinuities and observation on field manifestations for landslide and related slope instabilities were carried out. For digitizing, data processing, and analysis purposes, A GIS environment was used. In applying the SSEP rating scheme, the relative contribution of each of the intrinsic causative and extrinsic triggering factors were evaluated and ratings were assigned for each factor facet-wise. The intrinsic parameters considered are; slope geometry, slope material, structural discontinuities, land use land cover, and groundwater condition whereas, the external triggering factors are; seismicity, rainfall, and man-made activities. The total of all ratings for causative intrinsic parameters and external triggering factors are represented as Evaluated Landslide Hazard (ELH) established on which the study area is divided into different hazard zones as per the SSEP rating scheme. Then after these the LHZ map of the study area was produced. The prepared LHZ map has identified three zones, namely Very High Hazard (5.12%), High Hazard (66.73%) and Moderate Hazard (28.15%). Finally, the LHZ map was overlaid by past landslide event data out of which 12 % have fallen in the Very High Hazard zone, 72% High Hazard zone the rest 16 % fall in the moderate hazard confirming the validity of the prepared LHZ map. Thus, the satisfactory validation confirms the rationality of considered parameters, the adopted SSEP technique, and the tools and procedures in developing the LHZ map of the study area.
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Landslide Hazard Zonation (LHZ), Evaluated Landslide Hazard (ELH), Intrinsic, Extrinsic, Ameya Ethiopia