Assessment of Landslide Susceptibility using the AHP and GIS Techniques for the Zurbatiya Region, East of Iraq

Abstract

The present study adopts AHP and GIS techniques to produce a landslide susceptibility index map of the Zurbatiya region. The research area is located in eastern Iraq, within Wasit Governorate. The local terrain predispositions were represented by the landslide conditioning parameters that were chosen: slope angles, geology, slope aspect, topographic elevation, distance from faults, and distance from valleys. The spatial resolution used for the raster-based study is 12.5×12.5 m. The AHP scale determines the relative importance of each element, with the slope angle having the largest weight (9) then geology and slope (7), aspect and elevation (5), and distance from faults and distance from valleys having the lowest relative importance (3). Depending on the landslide susceptibility index map, the low landslide susceptibility class has the highest percentage (41.2%) for the whole region, followed by the moderate landslide susceptibility class, which its share (39.9%), then the high landslide susceptibility class, with its share (14.8%), where, the very high share (3.9%). The landslide susceptibility index map was tested within the fieldwork stage in which 14 stations are selected within these four zones (low, moderate, high, and very high) where stations 1, 3, 4, 6 and 7 are distributed within the very high zone, station (8) within the high zone, stations 2, 9, 10 and 12 within the moderate zone and stations 11,13 and 14 within the low zone. Finally, it can be seen that they are an exact match when comparing the landslide susceptibility index map with the fieldwork stage, which is based on the previous failures and which are expected to occur. Toppling and Rock fall found within in the study area, in addition to the rolling that occurs later for the separated blocks by failure.