Sinkholes in the Friuli Venezia Giulia Region: state of the art of the of territorial analyses in the evaporites

Sinkholes are a well-known phenomena in the Italian peninsula even if a comprehensive and detailed inventory is far away to be complete, in fact, every single region faces with the phenomena according to its occurrences and to the damages caused to the infrastructures. In the Friuli Venezia Giulia (FVG) Region the first approaches have to be addressed to Marinelli at the end of the 1800. But only in the seventies some specific studies linked to the structural problems that these subsidence phenomena caused to the buildings started. In the FVG Region, sinkholes are quite frequent in specific areas where gypsum is exposed or mantled, especially in some alpine valleys where evaporites acted as a tectonic lubricant during the main alpine orogenetic compression phases. In these areas, hundreds of phenomena have been identified thanks to a project funded by the Geological Survey. From a data analyses emerge that the sagging sinkholes are not present, while collapse sinkholes and cover suffosion sinkholes are the most frequent. A huge amount of bedrock collapse and caprock collapse sinkholes have been identified on the slopes in the mountain areas. The geological and geomorphological surveys pointed out as also some inhabited villages and infrastructures are heavily affected by active sinkholes which damaged some houses and roads. The recognition and identification of these phenomena and their outline are at present and will be in the future an important background to consider while facing with the territorial planning.