Landslide susceptibility mapping in the Adwa Volcanic Mountain Plugs, Northern Ethiopia: a comparative analysis of frequency ratio and analytical hierarchy process methods

Abstract

Landslides are a widespread occurrence in various regions across the globe, and Ethiopia serves as a typical example. The objective of this research was to develop and evaluate a landslide susceptibility map (LSM) using two different approaches: the frequency ratio (FR) and analytical hierarchy process (AHP). The suitability and effectiveness of both approaches were assessed for the specific study area. In the initial phase, a total of 175 past landslides, covering an area of 13.09 km2, were identified and mapped for further analysis. Eight causative factors, including elevation, slope steepness, slope aspect, lithology, distance from fault and stream, precipitation, and land use/land cover, were selected and mapped accordingly. Subsequently, a landslide susceptibility index (LSI) was calculated based on the relative influence of these factors on the recorded past landslides. The resulting LSMs were then categorized into five zones representing varying degrees of susceptibility: very low, low, moderate, high, and very high. For the LSM derived from the FR approach, the very high and high susceptibility zones accounted for 16.65 km2 (7.58%) and 79.96 km2 (36.4%) of the total area, respectively. Conversely, for the LSM derived from the AHP approach, these values were 21.9 km2 (9.99%) and 68.9 km2 (31.37%). Generally, both the FR and AHP approaches yielded comparable results. The LSMs were validated using the area under the curve (AUC) method. The FR model exhibited higher accuracy and prediction rates, with values of 0.807 and 80.7%, respectively, compared to the AHP model with values of 0.756 and 75.6%, respectively. These generated LSMs offer valuable insights for identifying and addressing the requirements of landslide hazard mitigation and adaptation.