Source model of surface deformation and seismicity at the Campi Flegrei

Jinhui Cheng, Mateo Acosta, & Jean-Philippe Avouac

Submitted September 7, 2025, SCEC Contribution #14865, 2025 SCEC Annual Meeting Poster #TBD

Campi Flegrei, a restless caldera near Naples, Italy, has experienced significant uplift and seismicity over the past two decades in relation to magmatic and hydrothermal processes. In this work, we consider inflation of a shallow reservoir, constrained by seismic Vp/Vs anomalies, as the source of the observed deformation and use the integrated Flow2quake framework, which combines reservoir, geomechanical, and seismicity modeling, to determine an inflation history consistent with the surface deformation and observed seismicity. To constrain the the time‑dependent volume changes of the reservoir, we integrate multi‑year InSAR (Sentinel‑1 and COSMO‑SkyMed) and continuous GPS (cGPS) observations. We first apply Principal Component Analysis (PCA) to the InSAR time series and cGPS data to extract coherent deformation signals and reduce atmospheric and orbital noise. These signals are then inverted using a multi‑dataset geodetic inversion, which employs poroelastic Green’s functions. Our results show that the surface deformation is well explained by volume variations in the shallow source, likely due to hydrothermal activity. The reconstructed volume change history is used to calculate Coulomb stress changes, which are assumed to drive the seismicity, and test the if shallow reservoir volume changes can explain both the ground deformation and the seismic activity at Campi Flegrei. This study place new constraints on the source of deformation and improve understanding of the processes driving Campi Flegrei’s ongoing unrest.

Citation
Cheng, J., Acosta, M., & Avouac, J. (2025, 09). Source model of surface deformation and seismicity at the Campi Flegrei. Poster Presentation at 2025 SCEC Annual Meeting.


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Tectonic Geodesy