GIS-Based Statistical Analysis for Evaluation of Landslide Susceptibility Mapping a Case Study in Blue Nile Gorge Gohatsion-Dejen Road Section Central Ethiopia
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Date
2021-09-06
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Addis Ababa University
Abstract
The present study was conducted in Blue Nile Gorge Gohatsion - Dejen road section about 185 km from the capital city Addis Ababa. It has been well recorded that the Blue Nile Gorge Gohatsion-Dejen section road corridor was sufferer in different landslides and slope failures. The main objective of the present study was to evaluate landslide susceptibility of the road corridor and produce its landslide susceptibility map. To realize the objectives of this research statistical information value model was basically followed. Seven causative parameters: namely; lithology, elevation, slope, aspect, land use/land cover, proximity to road and proximity to streams were considered for landslide susceptibility evaluation and map preparation. The landslide inventory mapping in the corridor was administered through field observations and Google Earth image interpretations. For statistical information value model the inventory landslide and causative factor maps were converted into the same pixel size raster format then depending on the influence of causative factors on past landslide the information values were calculated. After the statistical information value calculation, distribution of landslide over each causative factor maps was obtained and analyzed. Weights for the class within these causative factor maps were obtained by using statistical information value model. Causative factors are classified into various classes; based on landslide concentration, topographic condition, geology and land cover types in the road corridor/study area. As the statistical information value analysis result; causative factor classes of colluvium deposit, 1575–2100m elevation, > 450 slope, east facing slope aspect, bare land, 0-0.5km distance from road and 0-50m distance from streams have maximum contribution for a landslide occurrence. The landslide susceptibility map, thus produced in the study area clearly indicates that 43.2km2 (17.0%), 96.8km2 (38.1%) and 113.9km2 (44.9%) falls in low, moderate and high susceptible classes respectively. Validation of the prepared susceptibility map revealed that 87.1% of past landslides fall in high susceptible class of the prepared landslide susceptibility map (LSM). Thus, the landslide susceptibility map (LSM) validation provided acceptable results and the different classes those delineated can be safely applied for future developmental planning in the present study area.
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Keywords
Blue Nile Gorge, Information Value Model, Landslide, Landslide Susceptibility, Landslide Susceptibility Index