## 4 Results
Figure 4: A-DInSAR velocity of displacement maps (mm / yr) of the Zelazny Most tailings dam for the period October 2014–April 2019; (**a**,**b**) velocity in LOS ascending and descending orbital geometry respectively; green PSs are considered as stable; yellow-red PSs are moving away from the satellite; cyan-blue PSs are moving toward the satellite; (**c**) velocity in east-west direction; cyan-blue PSs are moving eastwards; yellow-red PSs are moving westwards; (**d**) velocity in up-down direction; yellow-red PSs are moving downward. As regards the time series of east-west displacements (Figure 5b), the eastward displacements are shown in blue, and westward displacements are in red. Also in this case, the trend of the time series shows larger cumulative displacements values for points located near the beach and the ponds (P1 ew and P2 ew) compared to the points at the foot of the dam (P3 ew and P4 ew). However, such difference in the horizontal deformation patterns is very weak in the western sector of the dam, where the displacement towards the west (or towards the outside), seems to take place as an en bloc movement. The displacement pattern in space has been investigated through two cross sections parallel to the dam body, along the eastern and western embankments (Sections 1 and 2, located in Figure 6a,b). The cross sections run at a middling altitude of the dam body. Each curve of the section graphs (Figure 6c-f) represents the A-DInSAR displacement profile of the dam at that height, for each analyzed year. In particular, the curves of the graphs show the cumulative deformation that affected those sectors of the dam up to September of each  
Figure 5: Time series of displacement for the Zelazny Most TSF; **(a)** time series of up-down displacements for the northern, southern, eastern and western sectors of the dam; downward displacements are in red; **(b)** time series of east-west displacements for the eastern and western sectors of the dam; eastward displacements are in blue, westward displacement are in red. The location of the PSs selected for processing the time series is also shown in the map panels. year, and therefore the used time span is from October 2014 to September 2018. Greater distances between the graph curves represent higher velocities of displacement. Section 1, which concerns the eastern dam, shows that the eastern perimeter of the dam does not deform uniformly, but the central zone of the section shows more intense displacement, both in the horizontal (Figure 6c) and vertical directions of movement (Figure 6d), with maximum cumulative displacement of 80 mm eastwards and 100 mm downward, in about four years. As discussed above, higher deformation values are expected at higher altitudes of the dam, and lower values are expected at the base of the dam. Section 2, along the western dam, instead shows a uniform pattern of deformation both in the horizontal (Figure 6e) and vertical directions (Figure 6f), with maximum horizontal cumulative displacements similar with respect to the eastern sector (about 80 mm), but in the opposite direction (i.e., westwards), and the cumulative subsidence is around 60 mm in about four years.