نقشه برداری حساسیت فروچاله توسط فرآیند تحلیل سلسله مراتبی AHP و روابط بزرگی-فرکانس

ABSTRACT Sinkhole susceptibility mapping using the analytical hierarchy process (AHP) and magnitude–frequency relationships: A case study in Hamadan province, Iran

During the last two decades, sinkholes have become a major concern in some regions of Iran due to the hazard increase, mainly induced by groundwater over-exploitation. “Forochaleh” is a Persian word used to designate sinkholes; enclosed depressions with internal drainage developed in karst terrains. In the Kurdish language, “barqe chal” means sudden collapse, whereas “noor” refers to karst sinkhole (Taheri and Hashemi, 2011). The term “doline” is mainly used by European geomorphologists, whereas sinkhole is the most common term in North America and in the international literature dealing with engineering and environmental issues associated with karst (Gunn, 2004; Gutiérrez et al., 2008a, 2014). Words like collapse and sinkhole are also used by some authors to designate depressions and holes generated by subsidence phenomena related to anthropogenic cavities like mines, dwellings, catacombs, and other underground excavations (e.g. Parise, 2012, 2013). In this work we follow the genetic sinkhole classification proposed by Gutiérrez et al. (2008b, 2014), which covers the whole range of subsidence mechanisms observed in both carbonate and evaporite karst. Some of the main topics addressed in the scientific literature related to sinkholes include their nomenclature and classification (White, 1988; Waltham et al., 2005; Gutiérrez et al., 2008b), formation mechanisms (Tharp, 1999, 2002; Gutiérrez and Cooper, 2002; Salvati and Sasowsky, 2002; Karimi and Taheri, 2010; Heidari et al., 2011; Parise and Lollino 2011; Zhou and Beck, 2011; Shalev and Lyakhovsky, 2012), detrimental effects on human structures (Gutiérrez and Cooper, 2002; Fidelibus et al., 2011), role played on aquifer contamination (Lindsey et al., 2010), interaction with engineering projects and remediation (Waltham and Fookes, 2003; Milanović, 2004, 2011; Tolmachev and Leonenko, 2011; Galve et al., 2012a; Song et al., 2012). One of the issues that has received greater attention in recent years is the development of susceptibility and hazard maps aimed at predicting the spatial distribution, or spatial and temporal distribution of new sinkholes, respectively. These models may be produced through several approaches, like zonings delineated on the basis of expert judgments (Edmonds et al., 1987; Bruno et al., 2008; Kaufmann, 2008), the analysis of geophysical data (Batayneh, 2006; Pueyo-Anchuela et al., 2009; García-Moreno and Mateos, 2011; Margiotta et al., 2012), and data on peak ground acceleration (Papadopoulou-Vrynioti et al., 2013). Galve et al. (2008, 2009a,b, 2011, 2012b), in a series of papers, propose a complete methodological sequence for sinkhole susceptibility, hazard and risk assessment, as well as for the identification of suitable and cost-effective risk mitigation solutions. The main steps of the work flow, performed in a GIS environment, include: (1) development of multiple susceptibility models based on the distribution of inventoried sinkholes, on the one hand, and on the statistical relationships between the sinkholes and different sets of conditioning factors, on the other hand; (2) quantitative and independent evaluation of the prediction capability of the models and selection of the most reliable one; (3) transformation of the selected susceptibility model into a hazard model considering the temporal frequency of sinkholes in each susceptibility class, and incorporating a magnitude–frequency scaling relationship; (4) production of risk models combining the hazard model with data on the vulnerability of the human elements; and (5) assessment of the cost-effectiveness of different mitigation measures and layouts performing a cost–benefit analysis.

The sinkholes in the northern plains of Hamadan province, Iran, have been the focus of numerous studies, but most of them have been produced in Persian (Zamiran Consulting Engineers, 2003; Amiri, 2005; Taheri et al., 2005 and references therein). In two international publications, Karimi and Taheri (2010) and Heidari et al. (2011) presented some GIS-based thematic maps, but did not develop any predictive model or assessed probability of sinkhole occurrence. This work presents for the first time sinkhole magnitude and frequency relationships and sinkhole susceptibility maps of the Kabudar Ahang and Razan– Qahavand plains in northern Hamadan province, western Iran, applying the analytical hierarchy process (AHP) approach. This method was used by Jiang et al. (2005) to produce a country-wide sinkhole susceptibility zonation in China assigning weights to qualitative variables. To our knowledge, this is the first contribution that explores the practicality of the AHP method to assess sinkhole susceptibility in a specific region and incorporating quantitative variables, and one of the very few articles that makes an attempt to generate magnitude and frequency scaling relationships with a comprehensive sinkhole inventory (Galve et al., 2011).

The approaches illustrated in this paper could be satisfactorily applied in the growing number of areas worldwide affected by sinkhole damage. The increase in the sinkhole hazard and risk, similar to the region studied in this work, is frequently related to water table declines caused by aquifer over-exploitation (e.g., Waltham, 2008; Dogan and Yilmaz, 2011; García-Moreno and Mateos, 2011; Aurit et al., 2013) or dewatering for mining (e.g., Sprynskyy et al., 2009; Yang et al., 2015).