## 5 Results for AOI-1
### Anthropic Instabilities in AOI-1  
#### 5.1.1 Urban Areas  
Only \(\sim\)1% (19 km\({}^{2}\)) of AOI-1 is classified as urban, for which 82,789 PSs have been measured. Galway city (15 km\({}^{2}\)) represents 79% of the urban area and yielded 66,714 PSs. Only 5677 urban PSs are unstable (outside the \(\pm\)1.5 mm/year range), and most of these are located in Galway city. Here the unstable points are unevenly distributed in small clusters over the paved roads and in proximity to large buildings. An example of the clustered distribution of unstable PSs in Galway city, marked as 'a' in Figure 7, is seen in an area around the intersection of the N6 and N84 roads (Figure 9a). Urban development has here taken place on areas of largely fan peat (Figure 9b). Field reconnaissance revealed that the subsidence areas north and south of the road intersection correspond mostly to car parks (parking  
Figure 8: LOS velocity map of AOI-1 obtained from ENVISAT images with the PS-InSAR approach. SAR imagery date range: January 2003–October 2010. The sketch illustrates the satellite’s acquisition direction in respect to the orbit (**right**) and the LOS angle in respect to the vertical direction (**left**). Base image source: Esri, DigitalGlobe, GeoEye, Earth Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community. lots) that present uneven surfaces and several patches of recently repaired asphalt. The ground surface south of the intersection shows damaged surfaces and tilted light poles. The N6 and N84 roads themselves also show a few depressed and bumpy areas corresponding to the detected subsiding PSs. The highest subsidence rate of \(-8.4\) mm/year occurs at the N6/N84 intersection, the nature of which was changed from a roundabout to a signal-controlled junction at some time between 2012 and 2017 (Figure 9c,d). A similar pattern is observed in a semi-urbanized area marked as locality 'b' in Figure 7 and located north of Galway city along the N84 (Figure 10a). Here, the local subsidence zones correspond to recent land-use changes made to an area of cut-over raised peat (Figure 10b) between 2006 and 2011 (Figure 10c,d). These land-use changes include excavations, some extensions to industrial buildings and the construction of two 'halting sites' for mobile homes of the Trav  
Figure 9: Example of InSAR-detected subsidence in Galway city, denoted locality ‘a’ in Figure 7: PSs are superimposed on (**a**) the 2017 BlueSky aerial orthoimage and (**b**) a map of the Pleistocene-Holocene superficial deposits; the colors correspond to the legend in Figure 4b. The white circle marks the location of the extracted displacement time series (**e**). The urban development of the area at the N6/N84 roads intersection (marked by the yellow arrow) is presented in (**c**) and (**d**). ethnic group of persons native to Ireland). Field reconnaissance revealed some possible structural manifestations of ground movement, such as cracked or tilted walls and very uneven asphalt road surfaces, especially in the halting sites, which are apparently subsiding at rates of up to \(-14.4\) mm/year. Potential ground movements in Galway city were found also at locality 'c' in Figure 7, along the coastline (Figure 11). The example here is a 4-5 m high embankment made of metric-scale boulders and reinforced with cement cover (Figure 11a,b). A 200 m long section of this embankment is potentially affected by subsidence up to \(-6.4\) mm/year (Figure 11c). The movements are prevalently vertical, as confirmed by the results obtained with the ascending track. The visual inspection of the area revealed water seepage onto the tidal flat from underneath the subsiding section of the embankment. The seeping water possibly flows from a small stream and several ponds in an adjacent marsh and golf course located behind and upslope of the embankment. Fresh cracks in a few fixed boulders in the embankment were also visible during field reconnaissance.