Abstract:
Uatzau basin in northwestern Ethiopia is one of the most landslide-prone regions, which characterized by frequent
high landslide occurrences causing damages in farmlands, non-cultivated lands, properties, and loss of life.
Preparing a Landslide susceptibility mapping is imperative to manage the landslide hazard and reduce damages of
properties and loss of lives. GIS-based frequency ratio, information value, and certainty factor methods were
applied. The landslide inventory map was prepared from detailed fieldwork and Google Earth imagery
interpretation. Thus, 514 landslides were mapped, and out of which 359 (70%) of landslides were randomly selected
keeping their spatial distribution to build landslide susceptibility models, while the remaining 155 (30%) of the
landslides were used to model validation. In this study, six factors, including lithology, land use/cover, distance to
stream, slope gradient, slope aspect, and slope curvature were evaluated. The effects of the landslide factor of slope
instability were determined by comparing with landslide inventory raster using the GIS environment. The landslide
susceptibility maps of the Uatzau area were categorized into very low, low, moderate, high and very high
susceptibility classes. The landslide susceptibility maps of the three models validated by the ROC curve. The results
for the area under the curve (AUC) are 88.83% for the frequency ratio model, 87.03% for certainty factor, and
84.83% of information value models, which are indicating very good accuracy in the identification of landslide
susceptibility zones of a region. From these resulted maps, it is possible to recommend, the statistical methods
(Frequency Ratio, Information Value, and Certainty Factor Methods) are adequate to landslide susceptibility
mapping. The landslide susceptibility maps can be used for regional land use planning and landslide hazard
mitigation purposes.
