Geomorphic analysis in areas of low-rate neotectonic deformation: South Epirus (Greece) as a case study

• The study is focused on a geomorphic analysis of South Epirus (Greece), a region of low-rate active deformation.
• Geomorphic indices are useful for identifying tectonic activity even in areas of low rock resistance and high sediment supply.
• Segments of important active and potentially active faults covered by alluvial deposits have been identified.
• The location and the strike of the recognized faults coincide with drainage anomalies and deviations.

River morphology and the distribution of river deposits reliably reflect the neotectonic activity of a region in relation to rock resistance and climatic changes. Geomorphic indices have been used to identify landscape evolution and active faults, particularly in areas of high-rate tectonic deformation. In areas of low-rate deformation, the influence of neotectonic activity on landscape evolution is less apparent, although it is important. The aim of this study is to examine the region of south Epirus (Greece), a region where the rates of active tectonic processes are low. Because rock resistance is low and the sediment supply is intense in this region, the fault surfaces are either not well preserved or they are covered. For the purposes of this paper, geomorphic analysis (including the drainage basin asymmetry factor, the basin hypsometric curve and integral, the valley floor width-to-height ratio, longitudinal river profiles, the stream-length gradient index normalized by the graded river gradient, and the mountain front sinuosity index) was used to evaluate neotectonic activity and to identify covered, potentially active faults. In places where fault surfaces could be observed, geological mapping and tectonic analysis were applied to determine the fault characteristics. The first result of this work is that important active or potentially active faults extend for a significant distance into the alluvial plains of south Epirus. In this case study, we considered that geomorphic indices constitute a valuable tool for identifying neotectonic activity in regions of low-rate deformation. Furthermore, geomorphic analysis reveals the location of covered fault structures, contributes to evaluating fault capability, and therefore to estimating seismotectonic hazard.