Copernicus InSAR applications for the protection of Cultural Heritage: EO4GEO use case at Baia Roman Thermae

EO4GEO is an Erasmus+ Project aiming at defining a long-term and sustainable strategy to fill the gap between supply of and demand for space/geospatial education and training in the Copernicus domain. To test and validate the approach a series of training actions are ongoing for selected scenarios in three sub-sectors: 1) Integrated Applications, 2) Smart Cities, 3) Climate Change. ISPRA, which includes the Geological Survey of Italy, is contributing to the development of Integrated Applications, coordinating different scenarios fostering the uptake of EO data, services and standardized methodologies of analysis. Available EO data were tested to evaluate their effectiveness and efficiency in different fields (e.g. ground motion monitoring on Cultural Heritage, agro monitoring to support regional decision-making; land change detection, geohazard zoning, risk assessment, etc.). Here we present the preliminary results concerning the InSAR analysis and the development of different training actions on ground motion monitoring on potential slope instabilities affecting Cultural Heritage sites. The selected site is the Roman Thermae at Baia (Naples), being part of the “Parco Archeologico dei Campi Flegrei”, located close to active calderas. The area is characterized by a sequence (from the bottom to the top) of volcanic breccia, pyroclastic deposits and surge deposits; Phlegrean Fields represent an exceptional example of volcanic-related subsidence with unrest cycles characterized by intense ground uplift and lowering. The instability phenomena depend mainly on the acclivity of the top sector of the slope, with the activation of small collapse events, and on the lack of ordinary management and maintenance of the area (e.g. invasive vegetation, absence of drainage system). A preliminary InSAR analysis was performed exploiting ERS datasets (1993–2003), showing regional ground lowering, with deformation rates (5-10 mm/yr) that are consistent with the general down lift cycle affecting the whole area in that that period. Ongoing InSAR data processing are focused on SENTINEL-1 data (April 2016 - August 2020) allowing us to explore most recent evolution of instability phenomena. Data processing has been performed using the SeNtinel’s Application Platform (SNAP-ESA) and the Stanford Method of Persistent Scatterers (StaMPS). The dataset is composed by 79 descending and 81 ascending scenes, and the single master stack contains 76 interferograms from the descending and 80 from the ascending geometry. Additionally, SRTM DEM was used in the interferometric processing. Obtained results clearly show a ground uplifting in the investigated period, with displacement rates ranging between 5 and 10 mm/yr (5.2 mm/yr average value of the study area). Any differential displacement has been observed on the exposed elements of the site. A training module focused on this use case is under development, thus contributing to fill the gap between supply and demand in the Copernicus domain, main goal of the EO4GEO project. The definition of step-by-step methodology from EO data to final processing will be defined and connected to learning outcomes, sectorial and transversal skills contributing to finalize the main goal of the EO4GEO project.