AUTHOR=Intrieri Emanuele , Confuorto Pierluigi , Bianchini Silvia , Rivolta Carlo , Leva Davide , Gregolon Samuele , Buchignani Vincenzo , Fanti Riccardo 

TITLE=Sinkhole risk mapping and early warning: the case of Camaiore (Italy)

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2023.1172727

DOI=10.3389/feart.2023.1172727

ISSN=2296-6463

ABSTRACT=Sinkholes are ground collapses that can cause significant damage to infrastructure and buildings. Part of the risk represented by sinkholes is related to their abruptness and the difficulty in spotting in advance their exact location within a sinkhole-prone area. For this reason, urban planning informed by an accurate risk mapping and monitoring is one of the most effective ways to reduce the risk.
In this paper, we propose a two-folded procedure based on the examination of 11 years’ worth of ground displacement data measured by a ground-based interferometric radar in search of sinkhole precursors and on the generation of a sinkhole risk zonation map. Camaiore town (Italy), where a catastrophic sinkhole occurred in 1995 and extensive surveys and monitoring have been carried out since, is used as test site. The analysis of ground displacement data revealed that the town had not experienced subsidence relatable to incoming sinkholes in the monitored period; however, few cm of vertical movements, which are well correlated with water table oscillations, have been measured and are expected to be of the same order of magnitude of sinkhole precursor deformations, meaning that a phenomenon of the size and velocity of the 1995 event could have likely been detected before its final collapse. In order to generate a sinkhole risk map, we evaluate the susceptibility map as derived from a set of predisposing environmental parameters including the displacement data measured by the radar, the vulnerability from the thickness of the sedimentary cover that can be linked to the abruptness of the collapse, and the value of the elements at risk from the Italian Real Estate Market Observatory integrated with land cover information for the non-built up areas. This work also shows how a sinkhole risk map could contribute to identify specific areas that should be closely monitored using in situ and remote sensing instrumentation.