A review of tsunami hazard for southern Aotearoa New Zealand with implications for future research

Abstract

ABSTRACT Here we provide an overview of southern Aotearoa New Zealand’s tsunami hazard to promote awareness, enable enhanced preparation, and to act as a resource for further research. The Southland region of Aotearoa has a long length of coastline exposed to local, regional, and distant tsunami sources. In comparison with regions further north, Southland’s tsunami hazard has received less scientific attention. Information gathered from the National Tsunami Hazard Model 2021, tsunami databases, and local studies, indicates that Southland has a high tsunami hazard. Tsunami heights of 4–12 m can be expected at a 2500-year return period. Earthquakes at the Puysegur and Peru subduction zones are the most significant tsunami sources for Southland. Modelling of tsunamis triggered by great earthquakes at these boundaries suggests inundation of low-lying land is likely, especially around Invercargill and Riverton. Surveys of residents conducted by local authorities suggest tsunami preparedness is inadequate. Geological records of large earthquakes and tsunamis are lacking for Southland, and we acknowledge that such physical evidence has been important for education and preparedness campaigns in other parts of the country. However, we argue that the level of hazard is sufficient to warrant increased collaboration between scientists, emergency managers, and communities to improve preparedness.