The impact of the Ischia Porto Tephra eruption (Italy) on the Greek colony of Pithekoussai

摘要

The island of Ischia is an active volcanic field, whose activity dates back to more than 150 ka. From Neolithic times it experienced a complex history of human colonization and volcanic eruptions that destroyed settlements and drove away the population. Recent archaeological and volcanological research has demonstrated that humans have periodically had to face volcanic and related hazardous phenomena since at least the Greek foundation of Pithekoussai (8th century BC). During the 5th century BC a telluric event is reported by the historian Strabo to have caused the abandonment of a Syracusan military outpost on the island. In the volcanological literature the Ischia Porto Tephra eruption has been identified as the most likely culprit. The eruption formed a crater lake in the north-eastern corner of the island and emplaced a poorly dispersed pyroclastic deposit, composed of a sequence of magmatic and phreatomagmatic scoria- and pumice-fallout beds, interlayered with minor pyroclastic density current deposits. Recent excavations furnished clear evidence of the impact of this eruption on a settlement located on S. Pietro Hill, to the east of Ischia's harbour. The archaeological finds include mounds of building materials, pieces of decorative terracotta panels and a few terracotta antefix fragments. The spatial distribution of the material found, the presence of stacks of tiles and other building materials and the absence of any structural remains, suggest that this was a building site for the construction of a temple. As written sources confirm, although the site and the military garrison were abandoned, the colony survived.