Evaluation of Landslide Hazards Using the Landslide Possibility Index: The Influence of the Exposed Rocks on Landslides in Kirkuk-Koysinjaq Main Road, Northern Iraq

Landslides on slopes occur for various reasons and lead to significant economic losses, adverse influences on the environment, and fatal accidents. The newly constructed road within mountainous areas between the Shewan area and the Taq Taq district linking Kirkuk Governorate to Koysinjaq city experiences annual landslides. This paper aims to use the Landslide Possibility Index (LPI) system to evaluate the stability of slopes, identify the factors that control potential landslides and their severity, as well as the extent and scope of the risks to which slope faces are exposed. Four stations were chosen, data were collected, aerial photographs were studied, and detailed fieldwork was conducted to measure the ten LPI system parameters. The results show that the studied stations varied in failure possibilities, hazard zones, and categories, and that one of the main reasons for the slope failures in the study area is improper road cuttings with a steep angle to the slopes. There is clear control of the exposed rocks on the failures in the studied stations. The severe weathering of the claystone layers within the Bai Hassan Formation triggers secondary types of failures, which are governed by bottom weathering mechanism. Factors like failure to construct sewers or channels to drain rainwater, lack of ditches on the two side of the road, and the absence of fall-preventing techniques and slope stabilization solutions worsen the situation and escalate the hazard of failures.