Valutazione della suscettibilità agli sprofondamenti nella Piana del Fucino (Italia Centrale) mediante regressione logistica e analisi geospaziale

A preliminary sinkhole susceptibility analysis has been carried out in the tectonic depression of the Fucino plain (central Italy). The study is aimed at the identification of the conditioning factors that contribute to the formation of sinkholes, as well as to understand the processes that gen- erate them by using multivariate statistics and geospatial analysis. A susceptibility map, in which sinkhole prone areas are identified, was elaborated by using a logistic regression model based on the evaluation of the statistical relationships between the known sinkhole locations and a group of con- ditioning factors. Several geological and geochemical condi- tioning factors have been considered: soil gas concentrations (CO2, CH4, He, Rn), hydrochemistry (sulphate concentration in groundwater, electrical conductivity, calcite and gypsum saturation index), thickness of Pliocene - Holocene continental deposits and faults. Antropogenic factor, such as the density of authorized private wells for water supply, was also considered. The resulting logistic regression model highlights that high concentration of carbon dioxide, helium and methane in soil gases constitute the most significant factors governing the development of sinkholes in the Fucino plain. Minor factors are the thickness of continental deposits lower than 200m, the presence of faults, and the high electrical conductivity in groundwater. The antropogenic factor seems to be of particular importance, because the high density of wells for water supply can result in strong fluctuations in the water table of the aquifer. Areas with high susceptibility have been identified along the northern edge of the basin (Avez- zano-Le Mole and Pozzone area) and in the south-west, in the area between the middle channel and the villages of Luco dei Marsi and Trasacco.