Submarine ash megabed fed by far-traveled, shoreline-crossing pyroclastic currents from a large explosive volcanic eruption
Abigail Metcalfe, Tim Druitt, Katharina Pank, Steffen Kutterolf, Jonas Preine, Karim Kelfoun, Christian Hübscher, Paraskevi Nomikou, Thomas A. Ronge, Shun Chiyonobu, Olga Koukousioura, Adam Woodhouse, Sarah Beethe, Michael Manga, Iona McIntosh, Masako Tominaga, Carole Berthod, Hehe Chen, Acacia Clark, Susan DeBari, Ralf Gertisser, Raymond Johnston, Ally Peccia, Yuzuru Yamamoto, Alexis Bernard, Tatiana Fernandez Perez, Christopher K. Jones, Kumar Batuk Joshi, Günther Kletetschka, Molly McCanta, Antony Morris, Paraskevi Polymenakou, Xiaohui Li, Jean-Marie Nedelec, Hao-Yang Lee, Dimitrios PapanikolaouLarge explosive volcanic eruptions from island volcanoes deliver vast quantities of ash to the marine environment. While many of the transport pathways are understood, those from shoreline-crossing or submarine pyroclastic currents, and their transformation into water-supported gravity flows, remain poorly constrained. We report the discovery by International Ocean Discovery Program (IODP) deep drilling of a 200-meter-thick ash megabed buried in rift basins of the South Aegean Volcanic Arc. The >73–cubic kilometer ash deposit originates from the Kos Plateau Tuff caldera-forming eruption, which occurred 161 thousand years ago, >120 kilometers to the east. The ash forms a chemically uniform, graded megabed lacking bioturbation, interpreted as having been emplaced by a stream of eruption-fed turbidity currents. Bioclastic debris within the ash provides evidence of widespread destruction of marine ecosystems. Large volcanic eruptions can remodel the seafloor landscape, deposit thick ash turbidites, and destroy marine biota on island arc–wide scales in short-lived, catastrophic events.