
Development of a Medicane-induced Landslide Inventory; Case Study of 2023 Cyclone Daniel, Central Greece
Authors
Sotiris Valkaniotis, Maria Taftsoglou, George Papathanasiou, Domna Samara, Caterina Zei, Themistoklis Chatzitheodosiou
DOI
Abstract
Cyclone (medicane) Daniel was a devastating Mediterranean tropical-like cyclone that affected Greece during September 4-8 2023. Severe rainfall in central and southern Greece led to widespread landslides and flooding that caused more than 2 billions in damages. Flooding in Thessaly region surpassed 800,000 hectares, the largest recorded flood event in recent history. The area most affected by landslides and debris flows was the mountainous part of Western Thessaly, along Pindos mountain range, where severe mass wasting was also documented during Medicane Ianos in September 2020.
Using post-event satellite imagery (WorldView, Planet and Copernicus Sentinel-2), and field surveys a detailed inventory of more than 3,000 landslides was recorded within an area of 2,7000 km2. Numerous damaging debris flows and debris floods were also mapped along most of the major rivers and streams of this area. Most landslides were shallow landslides of few meters up to 20-30 meters, but also a major number of large (up to 0.2 km2) earth and rock slides were also mapped. The largest rock slide (Pirra landslide), documented in detail by a field and UAS survey, occurred at the ridgeline above Pirra settlement, Trikala region. Pirra slide created a landslide dam that blocked a small ephemeral stream and led to the creation of a small ~7,000 m2 lake that persists seven months after the event. The detailed landslide inventory shows a narrow concentration that is interpreted to be related with the significant local variations of heavy rainfall, and also a strong correlation with either highly susceptible geological formations or prehistoric/inactive large/giant landslides. The Daniel landslide inventory (2023) is also compared with the inventory of Medicane Ianos (2020), as they have a similar distribution along the same area, and also have a significant overlap.