## 5 Results for AOI-1
### Natural Instabilities in AOI-1  
#### 5.2.1 Landslides/Slope Instabilities  
Several small-scale coastal instabilities have been detected in AOI-1 (Figure 13). All occur at or near to the Cliffs of Moher in Co. Clare, and they are marked as localities 'h', 'i', and 'I' in Figure 7.  
Figure 12: Examples of ground instabilities affecting motorway and railway infrastructure in AOI-1: (**a**) M18 motorway south of Gort, denoted locality ‘d’ in Figure 7; (**c**) railway on the Galway-Limerick line, denoted locality ‘e’ in Figure 7. Maps of Pleistocene-Holocene superficial deposits and bedrock outcrop for each area are presented in (**b**) and (**d**); the colors correspond to the legend in Figure 4b. (**e**) Displacement time series of the points selected (white circles) for the motorway (**1**) and the railway (**2**).  
The maximum LOS velocities measured at each locality with the descending track are \(-\)5.1 mm/year, \(-\)2.8 mm/year and \(-\)16.9 mm/year, respectively. The maximum values obtained with the ascending track are respectively 6.4 mm/year, 2.6 mm/year and \(-\)8.9 mm/year. The movements at localities 'h' and 'i' have strong horizontal components, as confirmed by the analysis of the ascending track, which presents PSs with opposite velocity signs (Figure 13a). The main area of motion in locality 'I', located on the north side of the Hag's Head (Figure 13c), shows almost identical negative velocities in ascending and descending viewing geometries. The movements are mainly vertical, although, given the north-facing slope, a horizontal component of motion (not detectable by the satellites) cannot be precluded.  
Field reconnaissance of localities 'i' and 'I' revealed many features compatible with ground instability (Figure 14). At locality 'i', which occurs at a pronounced embayment in the cliff line, the cliff  
Figure 13: Example of slope instabilities occurring along the coastline in West Ireland (Co. Clare), as observed by descending (top row) and ascending (middle row) tracks. (**a**) Instability on the coast between the village of Doolin and the Cliffs of Moher, denoted locality 'h’ in Figure 7. (**b**) Instability at the Cliffs of Moher (white square), denoted locality ‘i’ in Figure 7. (**c**) Instability at Hag’s Head at the Cliffs of Moher, denoted locality 'I’ in Figure 7. Note that the northern flank of the Hag’s Head promontory is largely in shadow in this image. (**d**) The displacement time series of the selected point (white circle) is presented for the descending (**1**) and ascending (**2**) tracks.  
top comprises a veneer of glacial till overlying the Carboniferous rocks. Old walking paths along the cliff edge are now truncated by the cliffs, and the field boundary wall is locally tilted seaward (Figure 14a). Furthermore, the cliff face is relatively fresh looking (not lichen covered) and there is a fresh (active) talus/debris fan at the cliff base (Figure 14b). At locality 'I', the PSs correspond mainly to talus fields on the upper flanks of the Hag's Head promontory (Figure 14c). Immediately up slope of both talus fields are sharp scarps. The Carboniferous bedrock around Hag's Head shows marked local rotations and several fissures or cracks are observable between bedrock blocks (Figure 14d). Field reconnaissance and imagery from the Irish Coast Guard [59] further show that the cliffs here are undercut by a pronounced wave-cut notch and several sea caves.