**8. Conclusions**

The connection between Plio-Pleistocenic tectonic activity and geomorphological evolution in the Pardu Valley and Quirra Valley (Ogliastra, East Sardinia) was studied. The evolutionary conditions of the Pardu Valley are associated with a cycle of undeveloped fluvial erosion, which suggests a relatively young age of the engraving in relation to the capture by the Rio Pelau and the isolation of the Rio Quirra. The intense post-capture erosion has given the Rio Pardu Valley morphometric features that are favorable for the evolution of DGSDs. However, the Rio Quirra Valley presents paleo-DGSDs that have been fossilized by pre-capture terraced alluvial deposits.

The DGSDs' movements are linked to the recent tectonic evolution (areal uplift). The two valleys analyzed are controlled by transcurrent faults that have recently recorded low-magnitude seismic events. Therefore, it is possible that the constant movement of the DGSDs (between about 1 and 2 cm/y) may be susceptible to accelerations due to seismic triggering, causing the partial collapse of the slopes.

In particular, this research highlighted the following:


**Author Contributions:** Conceptualization, V.D., P.E.O. and G.D.; methodology, V.D. and G.D.; validation, P.E.O.; formal analysis, V.D.; investigation, V.D., P.E.O. and G.D.; resources, P.E.O. and G.D.; data curation, V.D.; writing—original draft preparation, V.D.; writing—review and editing, V.D., P.E.O. and G.D.; visualization, V.D., P.E.O. and G.D.; supervision, G.D. and P.E.O.; project administration, P.E.O.; funding acquisition, P.E.O. All authors have read and agreed to the published version of the manuscript.

**Funding:** Valentino Demurtas acknowledges the support from the University of Cagliari—Dottorato di Ricerca XXXIV ciclo—Earth and Environmental Sciences and Technologies.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable.

**Acknowledgments:** We are thankful to Reginald Hermanns for the precious suggestions. We are also grateful to Marie Bredal for the technical support in the InSAR processing. The precious contributions of the two anonymous reviewers and of the journal editors are acknowledged.

**Conflicts of Interest:** The authors declare no conflict of interest.
