02127nas a2200289   4500000000100000008004100001260001600042100001900058700001700077700001700094700001800111700001500129700001500144700001500159700001800174700002400192700001800216700001800234700001800252700002100270700002100291245012000312300000900432490000700441520137500448022001401823       2023                            d  c2023 Nov 301 aSarah Seabrook1 aKevin Mackay1 aSally Watson1 aMichael Clare1 aJames Hunt1 aIsobel Yeo1 aEmily Lane1 aMalcolm Clark1 aRichard Wysoczanski1 aAshley Rowden1 aTaaniela Kula1 aLinn Hoffmann1 aEvelyn Armstrong1 aMichael Williams00aVolcaniclastic density currents explain widespread and diverse seafloor impacts of the 2022 Hunga Volcano eruption.  a78810 v143 a<p>The impacts of large terrestrial volcanic eruptions are apparent from satellite monitoring and direct observations. However, more than three quarters of all volcanic outputs worldwide lie submerged beneath the ocean, and the risks they pose to people, infrastructure, and benthic ecosystems remain poorly understood due to inaccessibility and a lack of detailed observations before and after eruptions. Here, comparing data acquired between 2015~-~2017 and 3 months after the January 2022 eruption of Hunga~Volcano, we document the far-reaching and diverse impacts of one of the most explosive volcanic eruptions ever recorded. Almost 10 km of seafloor material was removed during the eruption, most of which we conclude was redeposited within 20 km of the caldera by long run-out seafloor density currents. These powerful currents damaged seafloor cables over a length of >100 km, reshaped the seafloor, and caused mass-mortality of seafloor life. Biological (mega-epifaunal invertebrate) seafloor communities only survived the eruption where local topography provided a physical barrier to density currents (e.g., on nearby seamounts). While the longer-term consequences of such a large eruption for human, ecological and climatic systems are emerging, we expect that these previously-undocumented refugia will play a key role in longer-term ecosystem recovery.</p>  a2041-1723