Understanding mariners' tsunami information needs and decision-making contexts: A post-event case study of the 2022 Tonga eruption and tsunami.

The 15 January 2022, Hunga Tonga Hunga Ha'apai volcanic eruption generated a tsunami that spread across the Pacific Ocean and prompted a tsunami advisory in Aotearoa New Zealand (NZ). Concurrently, a severe weather warning was issued for ex-Tropical Cyclone Cody, passing east of NZ and producing heightened swells along the North Island coast. Numerous boats were significantly damaged or sunk in Tūtūkākā Marina, Northland, NZ. Mariners raised concerns over the perceived lack of tsunami warnings. We interviewed mariners in Tūtūkākā to understand their experiences on the night of 15 January 2022 and their needs and expectations of tsunami warnings. The complexity of the multi-hazard event made it difficult to assess and convey the severity of the expected tsunami. We found that mariners require information about expected wave height and arrival time, weather, and sea conditions to inform their anticipatory mitigation actions. This event shows the importance of multi-hazard risk assessments to produce effective warnings and action advice.