The potential of satellite interferometry for geohazard assessment in cultural heritage sites

A continuous monitoring system of ground deformation, based on radar images acquired by ESA (European Space Agency) Sentinel-1 constellation, is active over the Tuscany Region (Central Italy). The potential of repeat-pass satellite SAR (Synthetic Aperture Radar) interferometry has been exploited to investigate spatial patterns and temporal evolution of regional and local ground deformation that affect cultural heritage sites. With millions of measurement points, ground deformation maps for Tuscany Region provide information that can be exploited to scan wide areas and to flag ground instabilities. These areas become targets for detailed analysis with high resolution sensors (e.g., COSMO-SkyMed satellites of the Italian Space Agency) to create a virtual constellation, in which different satellite data sources are synergically used to create a more effective and robust Earth Observation system. The potential of a virtual constellation is presented and discussed through the case study of Pistoia, a city whose origins date back to the Etruscan civilization.