Visibility of sinkhole and subsidence processes in the Lazio Region through combined spatiotemporal PS interferometric analysis and ancillary data integration

Abstract

The availability of periodic scans of the entire Lazio region through the European Ground Motion Service, EGMS release enables administrations to monitor vast areas, characterize ground deformation processes, classify Active Deformation Areas and prioritize Areas of Interest (AOIs). Within the framework of the agreement between the Lazio region and CERI–Sapienza, the analysis was extended to slow subsidence processes and potential sinkholes, integrating Sentinel-1 interferometric data provided by the European Ground Motion Service (EGMS, Copernicus) with geological and hydrogeological information. The 2019–2023 EGMS releases allowed the identification of 1,804 AOIs exhibiting coherent lowering along the Line of Sight, located mainly in alluvial and intermontane plains, associated in several sites with the presence of subsurface compressible deposits or hydrogeological discharge sectors, with approximately 5% situated within 500 m of known sinkholes. A subset of 1,369 AOIs is considered newly formed compared to the 2015–2021 interval: of these, 78 show velocities >6 mm/year and an area < 5 km2, with one-third situated in zones with high sinkhole susceptibility. The analysis of deformation time series allowed for the identification of Turning Points and Jumps, effective indicators of subsidence anomalies, signatures of impulsive ground deformation processes, and potential precursor signals of instability. Ongoing activities include data integration with geophysical surveys and remote sensing surveys, as well as the analysis of dual-geometry COSMO-SkyMed datasets over wider-timescales. The objective is to consolidate an integrated system capable of monitoring both slow deformations and precursors of sinkhole occurrence.