ORIGINAL ARTICLE Evaluation of karst features using principal component analysis (PCA): a case from Zarneh and Kergan, Western Iran Omid Ebrahimi 1 • Mehdi Ahmadi 2 • Himan Shahabi 3 • Shamsollah Asgari 4 Accepted: 26 June 2017 Ó Springer-Verlag GmbH Germany 2017 Abstract Zarneh and Kergan are two limestone mountains of the Zagros mountain range located in Western Iran. High-volume lime and relatively heavy rainfall have pro- vided a favorable condition for the development of karst features in the highlands of the Zagros mountains. The present study was carried out to detect karst features in the High Zagros Belt using satellite images. In this case, some aspects such as climate, structural criteria, and sub-criteria are affecting the formation of karst sinkholes and are identified in this study. The results indicate that karst fea- tures of sinkholes have originated from joints and faults which are caused by tectonic motions over time. In terms of spatial dispersion, the sinkholes are found at altitudes higher than 1900 m in Kargan and 2000 m in Zarneh. This proved the importance of altitudinal gradient, the role of moisture, and pleasant climatic conditions on the devel- opment of karst features in the study area. Keywords Karst  Geomorphology  Geohazard  PCA  Thermal remote sensing  Iran Introduction Karst landscapes in which dissolution of bedrock by water is the dominant geomorphic process characterize almost 20% of the continents and more than a quarter of the Earth’s population living on or near karst areas (Ford and Williams 2013). Karst as a type of landscape found on carbonate rocks such as limestone, dolomite, marble or evaporates (gypsum, anhydrite, rock salt) is characterized by a suite of landforms comprising of springs, dolines, caves, collapsed sinkholes, and carbonate depositional landforms (Gunn 2004; Hyland 2005). The study of karst landscapes is a field that geologists, hydrologists, geogra- phers, chemists, biologists, and other scientists are working towards comprehensive understanding. In addition, karst surveys are becoming increasingly important in environ- mental impact assessment studies (Veni 1999) and in the evaluation of disturbance in karst areas (De Waele 2009; Van Beynen and Townsend 2005). The use of modern technologies has allowed new methodological approaches for karst studies. This particu- larly applies to computer-aided investigations such as remote sensing and geographic information systems (GIS), which improve the generation of geomorphic maps and help monitor and mitigate karst geohazards (de Carvalho et al. 2014; Seif and Ebrahimi 2014; Siart et al. 2009). For geomorphological study, remote sensing is useful for covering large and inaccessible areas within a short time, and it has been a convenient tool in accessing, monitoring, and conserving karst landscapes. Due to the problems of field geomorphological studies in karst environments, currently the use of remote sensing in karst geomorpho- logic evolution assessment is increasing. Historical chan- ges and variations in the number and shape of karst depressions can be obtained from comparative studies of & Himan Shahabi h.shahabi@uok.ac.ir 1 Department of Geomorphology, Faculty of Geography, Kharazmi University, Tehran, Iran 2 Department of Geomorphology, Faculty of Geography and Planning, University of Tabriz, Tabriz, Iran 3 Department of Geomorphology, Faculty of Natural Resources, University of Kurdistan, Sanandaj, Iran 4 Researched Center of Agriculture & Natural Resources of Ilam, Ilam, Iran 123 Carbonates Evaporites DOI 10.1007/s13146-017-0373-2