Integration of Earth Observation data into land subsidence risk mapping: the Emilia Romagna region case of study (Italy)

The availability of Earth Observation (EO) data, which are nowadays freely accessible to an increasing extent, has significantly advanced large-scale monitoring capabilities for geological hazards, particularly in terms of acquisition frequency and areal coverage. This progress has been especially evident in monitoring land subsidence. By the first quarter of 2022, the Copernicus European Ground Motion Service (EGMS) began providing ground displacement data at the European level, offering valuable insights into surface movements across the continent. Despite the growing use of Interferometric Synthetic Aperture Radar (InSAR) for monitoring land subsidence, relatively few studies have focused on translating this EO data into comprehensive risk assessments.

The goal of this work is to develop a novel EO-based methodology for mapping land subsidence risks at regional scale. This methodology has been tested in the Emilia-Romagna region of Italy, an area historically affected by land subsidence due to both natural processes and anthropogenic factors. In this region, land subsidence rates have reached up to 7 cm/year since the 1950s.

To estimate the exposure and vulnerability of the region, we have utilized data from the World Settlement Footprint (WSF) Evolution and the Global Human Settlement Layer (GHSL), both of which offer crucial insights into the human settlements and infrastructure that could be impacted by land subsidence. Moreover, we have exploited EGMS ground displacement data to estimate hazard levels associated with differential settlement. The resulting land subsidence risk map identifies four distinct risk levels, ranging from low to very high, across various areas of Emilia-Romagna. It offers a user-friendly product helping land use planners and local authorities to better understand and mitigate the potential impacts of land subsidence in the affected areas.

This work is funded by the European Union – Next Generation EU, component M4C2, in the framework of the Research Projects of Significant National Interest (PRIN) 2022 National Recovery and Resilience Plan (PNRR) Call, project SubRISK+ (www.subrisk.eu; grant id. P20222NW3E), 2023-2025 (CUP B53D23033400001).