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Submerged flanks of volcanic islands are prone to hazards including submarine landslides 23 that may trigger damaging tsunamis and fast-moving sediment-laden seafloor flows (turbidity 24 currents) that break critical seafloor infrastructure. Small Island Developing States are 25 particularly vulnerable to these hazards due to their remote and isolated nature, small size, 26 high population densities and weak economies. Despite their vulnerability, few detailed 27 offshore surveys exist for such islands, resulting in a geohazard ‘blindspot’, particularly in 28 the South Pacific. Understanding how these hazards are triggered is important; however, pin-29 pointing specific triggers is challenging as most studies have been unable to link continuously 30 between onshore and offshore environments, and focus primarily on large-scale eruptions 31 with sudden production of massive volumes of sediment. Here we focus on a situation where 32 volcanic sediment supply produces a long-term elevation over a “normal” regime, which is 33 more similar to the long-term elevated sediment production cases at many sites (volcanic or 34 not) where human-induced vegetation change over-supplies sediments to coastal margins. We 35 address these issues by integrating the first detailed (2 mx 2 m) bathymetry data acquired 36 from Tanna Island, Vanuatu with a combination of terrestrial remote sensing data, onshore 37 and offshore sediment sampling, and documented historical events. Mount Yasur on Tanna 38 has experienced low-magnitude Strombolian activity for at least the last 600 years. We find 39 clear evidence for submarine landslides and turbidity …