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Abstract: Evaluation of karst hazards benefits from the integration of different techniques, methodologies and approaches. Each one presents a different signature and is sensitive to certain indicators related to karst hazards. In some cases, detailed analysis permits the evaluation of representativeness either from isolated approaches or by means of integrated analyses. In this study, we present the evaluation of an area with high density of karstic collapses at different evolutionary stages through the integration of surficial, historical, geomorphological and geophysical data in order to finally define the evolutionary model for karst activity development. The obtained dataset permits to identify different steps in sinkhole evolution: (i) cavities and open sinkholes, (ii) filling of these cavities, with materials having different signatures, (iii) the progression from collapses to subsidence sinkholes and (iv) enlargement through collapses in marginal areas of previous sinkholes. The presence of different stages of this evolutionary model permits to determine their own signatures that can be of application in contexts where analysis cannot be so systematic and also to evaluate the definition of the marginal areas of previous sinkholes as the most hazardous sectors.
Keywords: karst, sinkhole, geophysics, sinkhole inventory, Ebro Basin
Received 28 September 2016; Revised 31 May 2017; Accepted 1 June 2017
INTRODUCTION
The use of geomorphological analysis based on aerial photographs with stereoscopic coverage has been one of the most usual and useful approaches in the characterization of sinkholes and development of sinkhole inventories. Information for these inventories can be complemented by field inspection, records of infrastructures and building damages, inhabitant interviews and topographical analysis. All these data can permit the overall definition of the karst matter, its characterization and its historical recent evolution (e.g., Waltham et al., 2005; Cooper et al., 2011).
These datasets can allow to the exclusion of high susceptibility karstic zones in urban or infrastructure planning and also help in the evaluation of geological factors that favor karst sinkholes. This evaluation can also lead to understand the conditions that favor karst development in areas where historicalgeomorphological datasets are scarce or ambiguous, and to predict future unstable zones. These procedures can include heuristic, deterministic or statistical evaluations (e.g., Simón et al., 1991, Soriano & Simón, 1995; Simón & Soriano, 2002; Simón et al., 1998; Yilmaz, 2007; Lamelas et...