Mapping the ground displacements related to the 1 September 2025 seismic swarm at Campi Flegrei (Italy) caldera through multiple SAR sensors

Campi Flegrei caldera is an active volcano located in southern Italy, which is experiencing renewed uplift phenomena since 2005. This phase has also been characterized by an increase of seismicity, which, mainly since 2021, has experienced relatively high magnitude earthquakes.

In this work we analyze the ground displacements induced by the 1 September 2025 seismic swarm, whose main shock registered a magnitude (Md) of 4.0 in an area affected by a previously investigated uplift deficit.

This event has been analyzed by applying Differential SAR Interferometry (DInSAR) techniques to multi-sensor and multi-frequency SAR data. Indeed, we exploited acquisitions carried out by the Copernicus Sentinel-1 constellation (operating in C-Band), the Italian COSMO-SkyMed (CSK) and COSMO Second Generation (CSG) satellites operating in X-Band, as well as the SAOCOM-1A/B constellation of the Argentinian space agency, operating in L-Band. Furthermore, we benefited from an acquisition campaign carried out by the Capella Space SAR sensors (X-Band) operating in a Mid Inclination Orbit (MIO) configuration, thus allowing us to investigate the displacement component also along the North-South direction.

Such large data availability allowed us to compute a detailed picture of the displacements affecting the Earth surface across the earthquake, providing a significant contribution to the comprehension of the caldera dynamics, and opening new perspectives in active volcano monitoring scenarios.

 

This work has been partly funded by the Italian DPC, in the frame of INGV-DPC (2022–2025) and IREA-DPC (2025–2027) agreements: this paper does not necessarily represent DPC official opinion and policies. This research was also partially funded by HE EPOS-ON (GA 101131592) and the European Union-NextGeneratonEU through the following projects: MEET - PNRR - IR00000025; ICSC - CN-HPC - PNRR M4C2 Investimento 1.4 - CN00000013; GeoSciences IR – PNRR M4C2 Investimento 3.1 - IR00000037; Sustainable Mobility Center - MOST - PNRR M4C2 Investimento 1.4 - CN00000023; BAC MITIGATE - PNRR RETURN - PE00000005.