Abstract
Since 2005, the Campi Flegrei nested caldera volcano, located about 10 km west of Naples, Italy, has experienced accelerating uplift accompanied by increased seismicity, raising concerns in this densely populated area. This ongoing uplift is part of a millennium-long history of inflation-deflation cycles, in which seismicity correlates with uplift phases, albeit nonlinearly. Here, we show that the combination of stress shadowing and loading with frictional fault behavior reproduces the observed long-term seismicity trend. However, in the short term, earthquake clustering occurs, which we demonstrate is at least partly related to earthquake interactions and can be effectively modeled by overlapping aftershock sequences. Merging the long- and short-term approaches yields a combined model that effectively replicates the observed seismicity patterns. A pseudo-prospective test shows that the model can also provide probabilistic short-term forecasts of earthquake rates and maximum magnitudes on weekly to monthly time horizons.
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Data availability
The local catalog is provided by the Observatorio Vesuviano (https://terremoti.ov.ingv.it/gossip/flegrei), which we accessed on February 26, 2025. The HORUS catalog, which provides homogenized magnitudes for earthquakes in Italy since 1960, can be downloaded at https://horus.bo.ingv.it. The GPS data for the RITE station were extracted from Tramelli et al.8 and weekly reports compiled by the Observatorio Vesuviano (https://www.ov.ingv.it/index.php/monitoraggio-e-infrastrutture/bollettini-tutti/settimanali-dei-campi-flegrei). We linearly interpolated these data on equidistant time steps with a step size of 7 days between 1905 and February 5, 2025. The Python codes for parameter estimation and forecasting, as well as for reproducing the manuscript figures, can be found at the Zenodo repository (https://doi.org/10.5281/zenodo.18413119).
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Acknowledgements
We thank Yuan-Kai Liu and an anonymous reviewer for their constructive and insightful comments, which greatly helped to improve the manuscript. This study has been partly funded by the Deutsche Forschungsgemeinschaft (DFG)- Project-ID 318763901 - SFB1294, project B04. Open access funding provided by GFZ Helmholtz Centre for Geosciences, enabled by Projekt DEAL.
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S.H. Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Visualization, Writing—original draft, Writing—review & editing. T.D. Conceptualization, Investigation, Validation, Visualization, Writing—review & editing. A.T. Investigation, Data curation, Visualization, Writing—review & editing.
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Communications Earth and Environment thanks Yuan-Kai Liu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Teng Wang and Joe Aslin [A peer review file is available].
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Hainzl, S., Dahm, T. & Tramelli, A. A deformation-driven earthquake interaction model for seismicity at Campi Flegrei. Commun Earth Environ (2026). https://doi.org/10.1038/s43247-026-03296-3
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DOI: https://doi.org/10.1038/s43247-026-03296-3
