Geohazard assessment of the north-eastern Sicily continental margin (SW Mediterranean): coastal erosion, sea-level rise and retrogressive canyon head dynamics

Coastal dynamics are the result of several processes controlling the balance between sediment input and output over time. The beach system is not always able to maintain a neutral coastal balance due to natural and anthropogenic causes. We present an integrated marine geology, geomorphological and sea-level rise analysis in the coastal sector between Torre delle Ciavole and Capo Calavà (North-Eastern Sicily, Italy).This sector is characterized by high uplift rates and frequent seismicity (mainly generated by the very active Vulcano-Tindari Fault System), promoting the development of mass-wasting processes in the coastal and offshore sectors. A main erosive feature observed in the area is the head of the Gioiosa Marea submarine canyon, located at some meters of depth, few hundred meters far the coastline. The main morphological features of the canyon were reconstructed through the analysis of high-resolution multibeam data, indicating that the canyon is active, as also testified by the comparison of time-lapse aerial photos. Due to this active setting, the study area is exposed to multiple geohazards, among which we deal with: (1) retrogressive instability at the head of the Gioiosa Marea submarine canyon, (2) coastal erosion favored by the downlope funnelling of littoral drift at the canyon head, (3) flooding scenario at 2100 using the IPCC (Intergovernmental Panel on Climate Change) and Rahmstorf sea-level projections. The consequences associated with these geohazards are amplified by the strong anthropization pressures occurring along in this sector. Our results provide key insights regarding the future scenarios of this coastal sector, revealing the effects of the retrogressive activity associated with the canyon head on the coastal strip. We also present the first management tool for the application of forecasting studies by local administrations.