## 1 Introduction  
Ground deformation is a complex phenomenon that may derive from both natural (e.g., tectonics, landslides, and sinkholes) and anthropic (e.g., human-induced subsidence) causes. Natural- and anthropic-induced subsidence may act simultaneously [1] and, in some cases, areas affected by human-induced subsidence have been shown to be clustered within basins bounded by active faults [2, 3]. This makes the analysis of the ground deformation a very challenging task, especially in urbanized areas. Here, tectonic contributions to ground deformation may be disclosed by geomorphological, stratigraphical, and structural analyses [4], whereas anthropic contribution may be detected by geodetic analysis [5].  
Further difficulties in the recognition of the causes that drive ground deformation may derive from the location of the investigated urban area. In fact, natural (e.g., tectonic) contributions to ground deformation are very elusive in low seismicity areas. Difficultiesmay arise from the lack of surface evidence of ground motions (e.g., offset landforms and/or deposits), which could provide geomorphological and stratigraphical constraints to locate active faults. Such evidence is typical of moderate to high magnitude earthquakes regions [6; 7], whereas they may be rarely recognised in low-seismicity areas [8].  
In areas of scarce seismicity, geomorphological analysis plays a crucial role in locating active faults by identifying fault-controlled features, both in the topography and in the river network. This is particularly true when geomorphological analysis is combined with other techniques of investigation, e.g., geodetic, geophysical, and geological [8; 9; 10; 11; 12].  
The combination of different datasets may also allow the reconstruction of both the long-term (e.g., by means of geomorphological and stratigraphic data) and the short-term (e.g., by means of geodetic analysis) vertical motion history of a certain area. This approach has been adopted in different tectonic contexts, such as the Andes [10], the Himalayas [13], and the Central [14; 15] and Southern Apennines [4; 16] of Italy. It is worthy of note, that the classification of a fault as an active fault depends on the tectonic setting [17]. Here, we assume the definition provided by the Italian Civil Protection Department [18], which considers a fault as active if it was activated in the last 40 ka.  
In this study, we investigated a low seismicity urbanized area of the Southern Apennines in Italy. The target area of our study was the inner sector of the Sarno plain, along the Tyrrhenian sector of the Campania region. Here, recent vertical motions have been inferred over both long (e.g., from geomorphological and subsurface data [19; 20]) and short (e.g., GNSS and remote sensing analysis [1; 21]) time periods. The first dataset pointed to a tectonic contribution (e.g., active faulting) to the subsidence of the plain, whereas the latter dataset highlighted the anthropic loading. However, to date, the two datasets for this area have not been integrated and jointly interpreted. To address this issue, we used a multidisciplinary approach by combining geomorphological, structural, and subsurface stratigraphic data with geodetic, i.e., global navigation satellite system (GNSS) and differential interferometric synthetic aperture radar (DInSAR), and hydrogeological data.  
The aim of this multidisciplinary approach was: (1) to compare long-term vs. short-term vertical motions experienced by the study area; and (2) to verify if a relationship exists between the location of active faults and areas affected by human-induced subsidence.