## 1 Introduction  
Throughout the Quaternary period, coastal areas have undergone substantial transformations driven by many factors, including climate variability, ground motion, and other natural and anthropogenic factors and the consequent relative sea level rise (RSLR) [1, 2, 3, 4]. Morphological coastal changes are studied worldwide due to their social and economic impacts [5, 6, 7, 8, 9, 10, 11, 12]. The current understanding about past, present, and future SLR has been recently summarized by the Intergovernmental Panel on Climate Change (IPCC; [13]). The main findings are that (1) SLR has been faster in the past century compared to previous periods; (2) SLR has accelerated in the past two decades; (3) sea level (SL) will continue to rise over the 21 st century, and in the worst emission scenario (business as usual), the global SL will increase by about 1 m by 2100; and (4) the regional mean relative SLR will also continue to rise throughout the 21 st century, and will be accompanied by an increase in the number of extreme events, yielding increases in the frequency and severity of coastal flooding and erosion in low-lying areas. It should be noted that these global estimates do not include the effects of isostasy and tectonics, and should consequently be corrected, where possible, to include these factors [4; 14; 15]. The IPCC provides, usually once every three years, detailed reports which include, among other things, eusstatic data concerning the melting of glaciers; the most recent report, issued in 2022, includes predictions up to the year 2100. These are global data that do not consider other geological movements due to volcanism, tectonics, or isostasy [16; 17; 18; 19]. In addition to SLR, changes in coastal topography can be influenced by geological processes, such as tectonics, hydro-isostatic movement, volcanic activity, sediment flux, subsidence, and other related phenomena [17; 20; 21; 22], which act on a variety of time scales. This study does not attempt to disentangle the individual contributions of these geological factors. Instead, it leverages satellite-based Interferometric Synthetic Aperture Radar (hereinafter InSAR) observations to estimate the average trend of the vertical ground motion within the areas investigated. This approach is facilitated by data provided by the Copernicus European Ground Motion Service (EGMS) [23; 24], representing by far the most advanced and updated product for the characterization of the coastal environment. Through this methodology, we aim to provide a comprehensive assessment of how these geological dynamics collectively modulate flooding hazard, thereby enriching our understanding of coastal vulnerability in the face of climatic and geophysical changes. A detailed knowledge of the local SLR and ground motion is essential for accurately evaluating flood hazard in low-lying coastal areas [2; 4; 13; 25; 26]. Furthermore, climate change exerts significant influence on wind regimes and storm surges, potentially exacerbating flooding [27; 28]. Recent examples of coastal flooding in several countries are documented [29; 30; 31; 32]. RSLR can also produce serious damage to the built environment [27; 32; 33; 34; 35; 36], and this calls for the adoption of coastal protection and adaptation measures [37], based on a scientific assessment of the risks [38; 39; 40; 41; 42]. Despite the availability of global web-platforms such as the NOAA Sea-Level Rise Viewer, the Aqueduct Global Flood Analyser, and the Climate Central Coastal Risk Screening Tool [43; 44], which have played a pivotal role in raising public awareness about the immediate and future impacts of climate change and SLR, they still provide only large-scale information, leading to a potential overestimation of future flood risks [45; 46; 47; 48]. At the European level, scientifically validated data are provided by the Land, Marine and Climate Copernicus services, and by platforms such as Envri-FAIR and SAVECOAST [20; 49; 50; 51; 52].