Evaluating the susceptibility to anthropogenic sinkholes in Apulian calcarenites, southern Italy

Sinkholes are the main hazard related to underground voids of both natural and anthropogenic
origin. Instabilities developing underground may propagate upwards in a dramatic manner
and reach the surface in the form of a sinkhole. The Apulia region in southern Italy is an interesting
case study due to the outcropping of soluble rocks throughout the region. These rocks are affected by
karst processes and have a high number of anthropogenic cavities. The latter were excavated by
humans at different times for a variety of purposes. The worrying recent increase in the number
of sinkhole events registered in Apulia led us to collect information on natural and anthropogenic
sinkholes in Apulia. We focused on anthropogenic cavities, mostly excavated in Plio-Pleistocene
calcarenites, and characterized the rock masses before using two- and three-dimensional parametric
numerical analyses to model the instability processes, with the aim of exploring the failure mechanisms
that lead to the occurrence of sinkholes. The parametric studies allowed us to carry out a preliminary
evaluation of the stability conditions through simple charts designed for use in the field.