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Abstract

We compare the displacement patterns of the 1993-2000 subsidence and part (2015-2022) of the ongoing uplift at Campi Flegrei caldera, Italy.As for 1993-2000, we use a subset of the ERS-ENVISAT ascending- and descending-orbit LOS-displacement time series that were obtained by CNR-IREA through the SBAS DInSAR technique and which are in very good agreement with leveling data.As for 2015-2022, we use Level-1 SLC-IW Sentinel-1A imagery and create ascending- and descending-orbit LOS-displacement time series using SBAS within GMTSAR InSAR processing system; time series are in very good agreement with GNSS data.For each of the two time periods we combine LOS-displacements to obtain vertical and eastward displacements, and apply the Empirical Orthogonal Function analysis to these latter time series -- treated as a single data set -- to decompose space-time fields into separated modes, consisting of uncorrelated spatial patterns and associated temporal evolutions. We only retain the first mode, since it captures the main deformation during both investigated periods, is the sole mode related to long-lasting (years) processes, and is less affected by noise than original data.Our results: confirm that most of the deformation is related to the activity of a 3-4 km deep sill-like source, evidence ongoing deformation linked to local fluid migration in the Solfatara area; identify persistent deformation features where peculiar fluid migration processes occurred during the 1982–1984 unrest; and, most important, provide the first direct evidence of deep magma inflation at least since 2015, thus giving a strong warning of increasing risk at Campi Flegrei.