## 5 Discussion
### Accuracy of the Yearly DInSAR Displacement Rate and Its Decomposition
Even smaller areas and those with weaker displacement rates (e.g., eastern part of Muragl; Figure 5g,h) are congruently detected by both methods. Our results show similar accuracies as other studies with the SD ranging from 0.23 m up to 0.33 m after scaling compared to, e.g., the results of [PERSON] et al., 2020 [34] with an SD ranging from 0.20 m to 0.34 m. It is only at Davains that higher inaccuracies are observed because a larger proportion of the investigated area is affected by phase unwrapping issues (Figure 5k-m). However, the scatterplot shows similar good agreement for lower displacement rates (Figure 5m). Hence, the higher spatial sampling does not lead to higher inaccuracies in the aggregated yearly displacement rate and our approach is able to accurately detect movement. Based on an RMSE of around 10 cm (except Davains with more unwrapping issues) and visual inspection of value ranges in stable areas, we state that the lower detectable boundary with 6d interferogram stacks is at around 10 cm/a displacement, which is the limit for active rock glaciers [15]. Our results indicate slightly higher sensitivity than other recent studies [34; 43], which might be due to the longer time series used in the stacking procedure [41; 42; 77; 78] which results in a stronger dampening of arbitrary phase contributions from atmosphere or noise. Discriminating areas with displacement rates of less than 10 cm/a need longer temporal baselines [34; 43] and more sensitive methods such as small baseline subset (SBAS) InSAR should be used [41; 42; 45; 88]. * Visual assessment of the displacement maps shows that DInSAR lacks the ability to detect very high-resolution variabilities (e.g., Kaiserbergtal for the elevation change--Figure 4c,d, Nair for outlines of the smaller active lobes--Figure 5a,b). The coverage of such high-resolution spatial variations is more limited in the north-south direction due to the lower azimuth resolution (13.9 m) compared to the range (2.3 m) of Sentinel-1. However, the extent and variations on the scale of a few decimeters are captured well. Moreover, the systematic difference in the distribution of horizontal and vertical displacement at Kaiserbergtal (subsidence in western part; increasing horizontal movement towards southeast) agrees well in both methods (Figure 4). Spatialagreement in E-W displacement is also good in areas where less suitable conditions exist for DInSAR, such as areas adjacent to widespread layover and shadow at Gianda Grischa or strong northern orientation at Nair (Figure 5a,b,d,e). Even active areas with a direct northern orientation are highly detectable due to their vertical displacement contribution (see Appendix A Figure A1), which is evident for nearly all rock glaciers. However, neglecting the N-S displacement component leads to incorrect estimates, especially in the vertical displacement. This is twofold: (1) neglecting N-S displacement leads to a systematic increase in the vertical displacement component due to their similar behavior in LOS. (2) The contribution of slope in N-S direction to the vertical displacement component is neglected and, therefore, leads to an overestimation of elevation change in areas with strong N-S displacement. In conclusion, phase unwrapping remains a critical source of inaccuracy, which should be addressed by more advanced unwrapping techniques. The quantification of total annual velocity is difficult due to DInSAR being limited to stable surface conditions. However, the 6d DInSAR time series is capable of accurately detecting active rock glacier parts and spatial variations in movement rates and its direction on the scale of a few decameters, which provides valuable insights in movement dynamics and direction. Therefore, we can confirm the results of previous studies by successfully applying Sentinel-1 to map active rock glaciers [10; 34; 41; 42; 43]. Further, our results highlight that FT, DEM Differencing and DInSAR should be jointly used to derive total displacement from the former two and short-term dynamics from the latter one.