Tsunami

Geological samples provide evidence of tsunami that have occurred before human record. Marine sediment deposits in geological samples that are found significantly inland tell us that New Zealand has historically experienced tsunami that were many metres high and travelled many metres and even kilometres inland. We also search out data on the sources, damage and wave heights of tsunami in the recent past (the past 200 years). These data are used to calibrate mathematical models of inundation and impact.

We use data from the Pacific Tsunami Warning Centre, our DART network and our tsunami gauges to learn about characteristics of tsunami in real time and how they move through the Pacific. We visit sites in the Pacific where tsunami have recently occurred to learn more about the extent of the tsunami and the damage and hazards caused.

Modelling allows us to determine which parts of New Zealand’s coastline are most vulnerable to tsunami. We run hypothetical scenarios of potential future tsunami-causing events (earthquakes, volcanoes and undersea landslides) off the New Zealand coast and model the type of tsunami likely to occur under a given scenario. This helps us determine likely impacts on people, buildings and infrastructure. We also use modelling to determine the likely long-term economic losses to New Zealand cities from tsunami.

The central goal that underpins all of our research is to provide useful information that can be applied to predict and manage tsunami risk and hazards in New Zealand and overseas. Our research has been applied in a number of ways:

• We have built a national tsunami hazard model that predicts the maximum possible tsunami wave height for coastal areas throughout New Zealand.
• We prepare tsunami evacuation maps for Civil Defence and Emergency Management groups in New Zealand. These maps delimit possible tsunami inundation in populated coastal areas and identify key escape routes for people in the event of a tsunami alert.
• We research the awareness of geological hazards held by the public and the effectiveness of warning systems and public education programmes. This allows us to hone the advice we give regarding warning systems, public response, education and evacuation.
• We are collaborating with the National Oceanographic and Atmospheric Administration (NOAA), a US agency, on Pacific-wide tsunami research, which will eventually allow wave-height predictions in real-time. 

These applications build resilience in New Zealand’s coastal communities and build support networks with our Pacific neighbours.