ORIGINAL ARTICLE Rock fall susceptibility assessment along a mountainous road: an evaluation of bivariate statistic, analytical hierarchy process and frequency ratio Ataollah Shirzadi 1 • Kamran Chapi 1 • Himan Shahabi 2 • Karim Solaimani 3 • Ataollah Kavian 3 • Baharin Bin Ahmad 4 Received: 14 March 2016 / Accepted: 23 January 2017 Ó Springer-Verlag Berlin Heidelberg 2017 Abstract Few studies have been conducted for suscepti- bility of rock falls in mountainous areas. In this study, we compare and evaluate rock fall susceptibility mapping using bivariate statistical [weight of evidence (WoE)], analytical hierarchy process (AHP) and frequency ratio (FR) methods along 11 km of a mountainous road in the Salavat Abad saddle in southwestern Kurdistan, Iran. A total of 34 rock fall locations were constructed from vari- ous sources. These rock fall locations were then partitioned into a training dataset (70% of the rock fall locations) and a testing dataset (30% of the rock fall locations). Eight conditioning factors affecting on the rock falls including slope angle, aspect, curvature, elevation, distance to road, distance to fault, lithology and land use were identified. The modeling process and rock fall susceptibility mapping has been constructed using three methods. The perfor- mance of rock fall susceptibility mapping was evaluated using the area under the curve of success rate curve for training and prediction rate curves (PRC) for testing data- sets and also seed cell area index. The results show that the rock fall susceptibility mapping using the WOE method has better prediction accuracy than the AHP and FR methods. Ultimately, the weight-of-evidence method is a promising technique so that it is proposed to manage and mitigate the damages of rock falls in the prone areas. Keywords Rock fall Á Susceptibility Á Bivariate statistical method Á Weight of evidence Á Analytical hierarchy process Á Iran Introduction Rock falls are one of the major geomorphologic processes acting on steep mountain slopes (Whalley 1984). They represent the most intensely studied geomorphic process of the cliff zone in the mountain areas (Luckman and Fiske 1995). Mechanical weathering parameters, such as freezing and thawing (Hallet 2006; Matsuoka and Sakai 1999), and meteorological factors (D’Amato et al. 2016; Delonca et al. 2014; Sandersen et al. 1997) are main triggering factors for rock falls. Instability of slopes due to rock falls is a safety subject, especially when it affects important structures such as settlement buildings and roads. Uribe-Etxebarria et al. (2005) have cited that because of the economic effect of rock falls on roads with the traffic disruptions or delays, expensive remedial measures are remarkable. Ayalew et al. (2005) plotted schematically a flowchart of different methods to obtain the landslide susceptibility mapping. There are three main methods in the flowchart such as semi-qualitative, quantitative and hybrid. First method, semi-qualitative, is index-based such as simple ranking and rating (SRR) and analytical & Himan Shahabi himanshahabi@gmail.com; h.shahabi@uok.ac.ir 1 Department of Rangeland and Watershed Management, Faculty of Natural Resources, University of Kurdistan, P.O.Box 416, Sanandaj 66177-15175, Iran 2 Department of Geomorphology, Faculty of Natural Resources, University of Kurdistan, Pasdaran Street, Sanandaj, Iran 3 Department of Watershed Sciences Engineering, Faculty of Natural Resources, University of Agricultural Science and Natural Resources of Sari, Mazandaran, Iran 4 Department of Geoinformation, Faculty of Geoinformation and Real Estate, Universiti Teknologi Malaysia (UTM), Skudai, Malaysia 123 Environ Earth Sci (2017)76:152 DOI 10.1007/s12665-017-6471-6