Landslide Inventory Mapping and Susceptibility Analysis for the Jimma-Metu-Gore Transportation Route.

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Date

2025-12-01

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Addis Ababa University

Abstract

In Ethiopia, the frequency and magnitude of landslides, followed by the subsequent damage, have been increased in recent years. The Jimma-Metu-Gore route is located in the southwestern part of Ethiopia which is characterized as one of a landslide prone route suffering from the repeated consequences of the hazard. This research ultimately aims identifying landslide prone zones along the route using a quantitative approach known as CRITIC (Criteria Importance Through Inter criteria Correlation) method integrated with GIS techniques. Ten landslides are identified along the route and landslide assessment is conducted for each of the landslide stations. A detailed landslide inventory is first produced with the field investigations, satellite image interpretation and referring to existing records which served both as an input for factor analysis and as dataset for validation. Nine causative factors are carefully selected based on their relevance and data availability which are elevation, slope angle, slope aspect, curvature, rainfall, geology, use/land cover (LULC), proximity to streams, and proximity to lineaments. These thematic factors are extracted from high resolution datasets such as SRTM 30 m DEM, Landsat imagery, geological map and Ethiopian Meteorology Institute. Preparation of digitized layer maps of each of thematic factors are prepared employing ArcGIS tool and their weights are objectively determined using CRITIC method: Rainfall received the highest weight (0.159) among the nine factors followed by Proximity to streams (0.137), geology (0.127), Proximity to lineaments (0.124), elevation (0.071), slope angle (0.082), land use/land cover (0.109), curvature (0.095), and slope aspect (0.096). The final Landslide Susceptibility Map (LSM) is then developed and using Natural Breaks/Jenks method it is categorized into five susceptibility classes: Very Low Susceptibility (15.51%), Low Susceptibility (25.95), Moderate Susceptibility (29.39%), High Susceptibility (20.86%), and Very High Susceptibility (8.29%). Finally, based on the desk study, site investigation and landslide susceptibility analysis remedial measures such as construction reinforced retaining and installation of surface & subsurface drainage systems specifically tailored to each failure stations are proposed.

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Keywords

CRITIC, Landslide Susceptibility Map, DEM, Natural Breaks/Jenks

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