Inaccurate DInSAR Time Series Underlie the Purported Evidence of a Recent, Rapid Ascent of a Magmatic Body in the Campi Flegrei Caldera (Italy)

Highlights: What is the main finding? At Campi Flegrei, ground deformation time series derived from DInSAR and GNSS are not always consistent. What are the implications of the main finding? Inaccurate DInSAR ground displacement time series are the basis for the purported evidence of recent upward migration and shape changes of magmatic bodies at Campi Flegrei. Accurate DInSAR ground displacement time series seem to confirm that the shape of the Campi Flegrei ground deformation field has remained virtually unchanged over time. Ground deformation data are crucial for understanding the processes driving volcanic unrest. The current unrest at the Campi Flegrei caldera, Italy, presents a significant challenge, primarily due to the presence of inconsistencies between seismic data and recent ground deformation model outcomes. While there are no seismic indicators of magma movement during the period of unrest, the analysis of ground deformation yielded mutually contradictory results. Despite the indications from prior analyses that the shape of the ground deformation field remains almost constant over time, recent findings based on different DInSAR (Differential Synthetic Aperture Radar Interferometry) time series suggest the upward migration of an ellipsoidal magmatic body at shallow depths, as well as significant changes to its shape. These findings carry strong implications for the related volcanic risk. By comparing DInSAR and GPS (Global Positioning System) displacement time series in detail, we identified a bias in the DInSAR time series used to support the upward migration and shape changes in magmatic bodies. The results of this paper emphasize that the source of ground deformation during the current unrest at Campi Flegrei is quasi-stationary, with no clear evidence of magma migration.