An assessment of subduction zone-generated tsunami hazards in New Zealand Ports

For the role they play in domestic and international shipping and inter-island transport, ports are a critical part of New Zealand’s infrastructure network. With ports located along coastlines having similar exposure to tsunami hazards, multiple facilities could experience structural damage and operational disruption during a single event. In this study, we evaluated tsunami effects in terms of water levels and current speeds at 13 ports as caused by both local and distant source subduction zone earthquakes over a range of source moment magnitude scenarios. The results suggest that while the tsunami hazard varies between ports, it is generally highest along the eastern coastline due to its exposure to tsunami generated along the Southern Kermadec, Hikurangi and South American Subduction Zones. While a Hikurangi earthquake has the potential to generate the most devastating impacts at individual ports, an earthquake off the Peruvian coastline has the potential to impact operations and infrastructure at the largest number of ports. Such an event could affect international trade capacity, regional recovery and domestic inter-island transport. Due to the potential for damage and disruption at multiple ports in a single event, this study highlights the importance of a broader national and international transport system perspective to inform potential resilience investments.