2D and 3D seismic measurements to evaluate the collapse risk of an important prehistoric cave in soft carbonate rock

Abstract

The southern part of the Apulia region (the Salento peninsula) has been the site of at least fifteen collapse events due to sinkholes in the last twenty years. The majority of these occurred in «soft» carbonate rocks (calcarenites). Man-made and/or natural cavities are sometimes assets of historical and archaeological significance. This paper provides a methodology for the evaluation of sinkhole hazard in «soft» carbonate rocks, combining seismic and mine engineering methods.Acase study of a natural cavity which is called Grotta delle Veneri is illustrated. For this example the approach was: i) 2D and 3D seismic methods to study the physical-mechanical characteristics of the rock mass that constitutes the roof of the cave; and ii) scaled span empirical analysis in order to evaluate the instability of the crown pillar's caves.