## 1 Introduction  
Slope failures and mass movement phenomena are important hazards around the globe [1; 2]. Especially in tectonically active areas, steep slopes are characterized by deformed geological formations and sharp relief [3; 4]. Landslides and other such instabilities often cause significant impacts on infrastructure [5; 6], disruption of socio-economic activities, and numerous fatalities [7; 8; 9; 10]. Extreme weather events are one of the most common triggers of these failures [11; 12; 13; 14]. Especially around the Mediterranean region, shallow landslides and debris flows triggered by extreme climatic events have led to catastrophic impacts in the past [15; 16; 17; 18; 19; 20].  
Given that the region is one of the most sensitive to climate change across the globe [21; 22; 23] and that intense climatic events can potentially become more frequent in the future [24; 25; 26; 27], the increase in associated phenomena and hazards (i.e., floods, landslides and debris flows) can be a threat as well.  
The Mediterranean region is also dominated by high-value land uses, rich with important socioeconomic activity, including trade, tourism, transportation and others, especially along the coast [28; 29], making it highly vulnerable to the occurrence of natural hazards [30; 31; 32].  
Recent research has shown the competence of new technologies such as unmanned aerial systems (hereafter referred to as UASs) processed by structure-from-motion (SfM) photogrammetry and multi-view stereo (MVS) in mapping and measuring geomorphological features to acquire high-resolution topography data [33; 34]. Such approaches used in certain recent studies have illustrated that UASs can be a powerful tool for producing high-resolution terrain modeling, illustrating accuracy and shedding light into the dynamics of geomorphological processes [35; 36]. Photogrammetric processes, along with geomorphic analysis methodologies, have seen a rise in application in multiple fields of geosciences and surveying [37; 38]. Some of these applications focus on fluvial geomorphology [39], channel dynamics [40; 41], hydro-geomorphological processes [42], landslides, debris flows [43; 44], detailed topography [33], classification of fluvial geomorphological features and other geomorphic phenomena [38]. Most of these studies capitalize on photogrammetry's capacity for high-resolution mapping together with UAS' capabilities for rapid mapping [41].  
The complexity of mass wasting processes and the threat of climate change, together with the high exposure of infrastructure and high hazard levels in the Mediterranean coasts and their importance in local socioeconomic activities, highlight the need for an in-depth understanding of the extent and characteristics of slope failures and mass movement phenomena caused by extreme weather events. Monitoring these effects is important for minimizing disruptions from such events and is the basis for sustainable development. A deep understanding of the risks and the natural processes that create them, together with micro-zonation of high-value sites, can be a valuable tool so that these areas are able to retain their use, continue their socioeconomic activities with minimum disruption and at the same time keep high standards of safety [45; 46].  
In this context, the objective of the present study is to explore the capabilities of UASs in conjunction with photogrammetry in investigating mass movement phenomena along slopes through measurements of morphometric changes, shedding light into erosion/deposition processes, and delineate areas unsuitable for development. To this aim, this study explores the geomorphological impacts of Medicare Ianos (an extreme event that occurred in September 2020) in the area of the Ionian Islands in Greece, and specifically on the famous Myrtos beach, a highly touristic, tectonically active area, with a rich history of landslides [47; 48; 49; 50], investigating and discussing the advantages and disadvantages of the application.