Subsidence phenomena investigation on two archaeological sites on the Ionian coast by Earth Observation application

The Differential SAR Interferometry (DInSAR) has been applied for the monitoring and the investigation of deformation patterns of cultural and archeological heritage sites, with the aim of preserving their integrity and monitoring their conservation conditions. Here, DInSAR approaches were applied to monitor the subsidence phenomena occurring on the Ionian coast of Calabria region (Southern Italy), where several archeological sites of Greek origin are present. Two case-studies have been selected, the first concerning the heritage site of Sybaris, located in Sibari plain (Cosenza Province), where a deformation, up to 20 mm/yr, due to tectonic activity and glacio-eustatic factors and rapid urbanization, combined with the local ground water exploitation, has been recognized in the last years. The second case study refers to the vertical motion occurring in the Capo Colonna area (Crotone municipality), where the ruins of the Hera Lacinia temple are located. In this second site the subsidence trend, characterized by velocity up to 10 mm/yr, is probably due to the on-shore and off-shore gas extraction active in the area. The site geohazard is strongly increased also by the coastal erosion. The interpretation of the SAR data has been carried out on different SAR dataset, based on ENVISAT (2003-2010) images, as regards Sibari, and on TerraSAR-X imagery, in the time span 2008-2010 and 2014-2015, about the monitoring of Capo Colonna site, analyzed also with the availability in the area of corner reflectors installed in October 2014. In both cases we were able to detect and analyze the deformation trend with DInSAR techniques and to set up a procedure, based on the integration of remote sensing data and geological interpretation. Such procedure is aimed at the conservation of the two heritage sites and can be exported on other case study to improve the preservation and the management of the artistic patrimony spreading over the Italian territory.