Erosional processes in the natural-anthropic geosystem of Vulcano Island (Italy)

Vulcano, the southernmost island of the Aeolian Archipelago, has been characterized by an intense fumarolic activity since its last eruption from La Fossa cone (1888-1890). This island has a strong touristic vocation and frequentation, and here volcano-hydrothermal activity represents, at the same time, a landmark, one of the main causes of hydrogeological instability and a severe risk for human health. The space-time dynamic of this complex system is controlled by the mutual interactions among micro-meteorological, volcanic, tectonic, morphogenetic and anthropic processes.

La Fossa cone is affected by intense water erosion phenomena, also controlled by fumarolic activity as an obstacle for the growth of vegetation and a weathering factor. Man-made structures, with particular reference to deep modifications in the natural stream network induced by buildings and roads, exert a strong influence on these erosion processes, also fostered by episodic wildfires.

Another relevant theme is the acceleration of the coastal erosion processes in the Baia di levante area, driven by the circulation of chemically-aggressive hydrothermal fluids, which transforms the pristine volcanic minerals into phases like gypsum, anhydrite and clay minerals, significantly reducing the mechanical resistance of the rocks to the action of wave erosion. A general retreatment of the coastline (several meters in some locations) has been observed in the last twenty years, caused by the combined effect of volcanic activity, anthropic modifications and changes in sea level.