An Overview of Tsunami Hazards in the Southwest Pacific Ocean

The southwest Pacific region is geologically complex and exhibits all the principal causes of tsunami generation. While contemporary events and historical catalogs indicate that trans‐Pacific tsunamis have affected this area (∼18% of tsunamis reported globally), it is unique in that a large part of the tsunami effects over the ∼200‐year historical record were triggered locally and regionally. Furthermore, tsunamis in this region are caused by a wide range of earthquakes, volcanic eruptions, submarine landslides, or, more generally, a combination of mechanisms. Due to the complex nature of tsunami generation and the generally short amount of time to tsunami onset, mitigating tsunami hazards and informing vulnerable populations are particularly challenging. This article presents a comprehensive overview of the tsunami hazards in the southwest Pacific related to its complex tectonic and geomorphic setting through examples of significant historical events that exhibit different generation mechanisms, such as the deadly 2009 Samoa‐Tonga event and the recent tsunami caused by the 2022 Hunga Tonga‐Hunga Ha‘apai eruption. We also discuss data and knowledge gaps, including seafloor mapping, palaeotsunami studies, population distribution, and hazard and risk culture, underlining the urgent need to better understand tsunami phenomena, assess the associated risk, and prepare coastal populations for this hazard.