## 6 Conclusions  
We carried out a multidisciplinary analysis of the inner sector of the Sarno plain, in the Southern Apennines of Italy, with the aim of characterizing the subsidence experienced in both the short- and long-term in this area of low to moderate seismicity. We approached this problem by combining the geomorphological, stratigraphic, structural, hydrogeological, GNSS and DInSAR datasets. Comparison of all datasets allowed us to discriminate between the natural (i.e., tectonics) and the anthropogenic (i.e., groundwater pumping) contributions to subsidence in the Sarno basin.  
We identified a sector of the inner Sarno plain, named the Sarno basin, that experienced enhanced subsidence both in the long- and short-term. Geomorphological, stratigraphic, and structural data suggest that the Sarno basin is bounded by two faults (i.e., faults F1 and F2 in Figures 4 and 5) that show evidence of activity during the last 39 ka, and slip rates ranging from 0.1 to 0.25 mm/yr. We named these faults the Sarno Fault (fault F1) and the San Valentino Torio Fault (fault F2). Both are active faults, with the Sarno Fault also showing evidence of surface rupture, thus allowing for the interpretation that it is an active and capable fault. Notably, neither the Sarno fault nor the San Valentino Torio fault were included in any official national catalogues of active tectonic structures, e.g., the TIHACA [39] and DISS [84] databases.  
The geodetic data indicated that the Sarno basin is also currently experiencing subsidence, which has occurred for at least the past 30 years. This subsidence has a rate of 3-5 mm/yr and is localized in the area between the bounding faults of the basin. Hydrogeological data suggested that a significant part of this subsidence can be ascribed to groundwater pumping from the alluvial plain aquifer.  
We also determined that the fault activity and observed subsidence rate are related. In fact, fault activity caused the formation of the Sarno basin and the consequent accumulation of unconsolidated deposits, which are currently acting as amplifiers of subsidence that is mainly induced by groundwater exploitation.  
Finally, our multidisciplinary approach was proven to be reliable for the study of ground deformation in urbanized areas. In principle, it could be applicable globally. In the inner Sarno plain, further investigation might provide more data about active tectonics. These data might include new boreholes across both the Sarno and the San Valentino Torio faults, chronological analysis on datable stratigraphic layers (e.g., \({}^{14}\)C analysis of peat layers) and paleoseismological analysis.  
The following are available online at [[https://www.mdpi.com/article/10.3390/rs13163323/sl](https://www.mdpi.com/article/10.3390/rs13163323/sl)]([https://www.mdpi.com/article/10.3390/rs13163323/sl](https://www.mdpi.com/article/10.3390/rs13163323/sl)), Figure S1: Distribution of earthquakes epicentres and magnitude in the surroundings of the Sarno plain, Figure S2: Stratigraphy of the 71 boreholes used in this study.  
Conceptualization, E.V.; methodology, E.V., V.A., U.R., G.C. and D.D.M.; software, E.V., U.R. and D.D.M.; validation, E.V.; formal analysis, E.V., V.A., U.R., G.C. and D.D.M.; investigation, E.V., V.A., U.R., G.C. and D.D.M.; writing--original draft preparation, E.V., V.A., U.R.,G.C. and D.D.M.; writing--review and editing, E.V., V.A., U.R., G.C. and D.D.M.; supervision, E.V. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors wish to thank the editor and the anonymous reviewers, whose suggestions helped us to improve this manuscript.  
The authors declare no conflict of interest.