Age of submarine debris avalanches offshore Ischia island, Tyrrhenian Sea, Italy

Further 14C age constraints for the emplacement of historical and pre historical submarine debris avalanche and related to major collapses that affected the southern flank of Ischia island volcano are presented. Results are based on the stratigraphy of 11 gravity cores located in the southern offshore of the island and on new AMS analyses. The two collapsing events are: a) the Ischia submarine debris avalanche/debris flow, dated between ∼2.3 cal ka B.P. and ∼3 cal ka B.P.; b) a debris flow older than 23 cal ka B.P.. The Ischia debris avalanche, previously recognised mostly through marine geophysics, has an estimated volume of 1.5 km 3 and incorporates thousands of blocks that are still detectable over the sea-floor until 45-50 km from the island. Our results indicate an age of emplacement younger than previously held and support the still tentative hypothesis that a major catastrophic event occurred when the island was already inhabited by Greek settlers i.e. after the 7 th century b.C. The occurrence of at least two major collapsing events in the past 23 ka confirms the close genetic relationship between gravity failures and Mt. Epomeo uplift.