Evolution of the Tsunami Risk Management and Warning End-end System Over 18 years: A Myriad of Research, Guidelines, Standards, Tools and Remaining Gaps

Tsunami risk management in Aotearoa is built on a foundation of PTWC partnership following the 1960 Chilean tsunami, and earlier events over a wide range of scales. The current framework has been prompted by four major tsunami wake-up calls at 5-7 year fortuitous intervals since 2004. Roughly 14 key evidence and tool domains have been developed covering an end-end chain across modelling, mapping, design, awareness, communication, detection, forecasting, public alerting, signage, ports, engineering loading, etc. However, they have been developed out of sequence in response to opportunities often linked to those wake-up calls.

The tsunami research and mitigation community is now focused on revisions, integration and addressing substantial remaining gaps in key performance indicators, both in scientific creation of next-generation advice and public action on current advice. Key gaps include persistently low surveyed public evacuation rates and speed, and evacuation by car. There is also a lack of vertical evacuation buildings, with only one structure built for this purpose to date. Our ports and maritime infrastructure also remain underprepared for a major tsunami event. Each of evacuation rate and vertical evacuation improvements can save tens of thousands of lives, while tsunami response plans and hazard mitigation for ports could save millions of dollars in damage.

Important advances continue, especially faster detection and evaluation, wave size time-series forecasting, and potential techniques including satellite-based sea-level analysis capable of providing faster, more accurate, and some source-agnostic warnings. There is a strong need for widespread regular evacuation drills with social science-led support, education and evaluation; along with exploring other cognitive-decision focused interventions. Engineering of new evacuation buildings and retrospective analysis of existing buildings and port structures is critical. Closer dialogue is needed between emergency managers and tsunami forecasters ensuring the richness of novel tsunami early warning information can be effectively used in future responses.