Giant offshore pumice deposit records a shallow submarine explosive eruption of ancestral Santorini

Large explosive volcanic eruptions from island arcs pour pyroclastic currents into marine basins, impacting ecosystems and generating tsunamis that threaten coastal communities and infrastructures. Risk assessments require robust records of such highly hazardous events, which is challenging as most of the products lie buried under the sea. Here we report the discovery by IODP Expedition 398 of a giant rhyolitic pumice deposit emplaced 520 ± 10 ky ago at water depths of 200 to 1000 m during a high-intensity, shallow submarine eruption of ancestral Santorini Volcano. Pyroclastic currents discharged into the sea transformed into turbidity currents and slurries, forming a >89 ± 8 km³ volcaniclastic megaturbidite up to 150 m thick in the surrounding marine basins, while breaching of the sea surface by the eruption column laid down veneers of ignimbrite on three islands. The eruption is one of the largest recorded on the South Aegean Volcanic Arc, and highlights the hazards from submarine explosive eruptions.

Tim Druitt, Steffen Kutterolf, Thomas A. Ronge, Christian Hübscher, Paraskevi Nomikou, Jonas Preine, Ralf Gertisser, Jens Karstens, Jörg Keller, Olga Koukousioura, Michael Manga, Abigail Metcalfe, Molly McCanta, Iona McIntosh, Katharina Pank, Adam Woodhouse, Sarah Beethe, Carole Berthod, Shun Chiyonobu, Hehe Chen, Acacia Clark, Susan DeBari, Raymond Johnston, Ally Peccia, Yuzuru Yamamoto, Alexis Bernard, Tatiana Fernandez Perez, Christopher Jones, Kumar Batuk Joshi, Günther Kletetschka, Xiaohui Li, Antony Morris, Paraskevi Polymenakou, Masako Tominaga, Dimitrios Papanikolaou, Kuo-Lung Wang, Hao-Yang Lee