The present short communication deal with the combine use interferometric Synthetic Aperture Radar (InSAR) and Offset Tracking (OT) processing techniques od SAR images to investigate the landslide motion and/or accelerations due to post cyclonic activity. The analysis was performed within a multidisciplinary research project (called RENOVRISK) over a vegetated area of the Cirque de Salazie (Reunion Island, France) using Sentinel-1 SAR data. The main novelty of the study is the jointly use of both InSAR and OT processing method that , applied to C-band SAR images with high acquisition frequency (12 days for Sentinel constellation), can be used to monitor slow-moving landslide motion also densely vegetated areas (generally bed covered) as well to identify and mapping fast moving areas. The paper is interesting for people involved in the mapping of new moving areas and in the kinematic characterization of mapped landslide areas. The designed research fits well with the purpose of the Journal with results that are encouraging which show a promising use of the combined proposed approach to detect moving area in high vegetated condition. From my point of view the paper can be considered for the publication in the present form.

The letter proposes the use of InSAR and offset tracking techniques on Sentinel-1 SAR data to monitor landslides in a vegetated area (Reunion Island). The work is interesting and suitable for publication in this journal, in the following detailed comments are provided.

1. As a general point, the quality of the figures should be improved, as they appear blurred.
2. Page 6, the authors state that “The OT technique is nominally less affected by temporal signal decorrelation than the InSAR technique. Therefore, we used all possible image couples, leading to the creation of 351 correlograms in both range and azimuth directions. Then, we applied a stacking procedure to create one velocity map in the range direction and one in the azimuth direction.” Is the matching identical for all couples? In other words, how is it ensured that the same points are identified for all image couples? And how are the offset values related to the matching point couples combined into one velocity map? A more detailed description of the algorithm should be provided.
3. Page 7. “Second, we can see a clear pattern of ground motion in the Hell-Bourg area, approximately ± 0.5 m/yr and spatially consistent with ground observations.”. The pattern of the Hell-Bourg area looks also quite complex and stating that it is “± 0.5 m/yr” may induce the reader that values are either +0.5 or -0.5 m/yr. It should be specified that ± 0.5 m/yr is the interval of values.
4. Page 7. “In this study, the InSAR signal was surprisingly coherent with a certain level of noise.”. This is an interesting result, but should be justified by showing the InSAR coherence map.
5. The azimuth and LOS OT velocity maps are shown in Figure 3. These maps have a uniform spatial sampling. However, the image matching techniques usually yield a non-uniform grid. Is this true also in this case? If so, was the spatial grid interpolated?
6. The notation in equation (1) is not very clear and should be improved using symbols. This applies also to Figure 4.