Home / Our Science / Natural Hazards and Risks / Tsunami / Tsunami in New Zealand

Tsunami in New Zealand

Has New Zealand been hit by tsunamis?

New Zealand has experienced about 10 tsunamis higher than 5m since 1840. Some were caused by distant earthquakes, but most by seafloor quakes not far off the coast.

2013 Tsunami Report

A nearby coastal seafloor earthquake is the only warning people may get before a tsunami arrives. Such a tsunami can arrive within minutes - before there is time to issue a warning. Distant earthquakes give more warning time. Some tsunamis are turbulent, foaming walls of water filled with debris and sand that crash ashore and sweep inland. Others are just rapidly rising or falling water levels over minutes to an hour. Both are dangerous. Both can travel over land at speeds faster than a person can run. The turbulent surge is invariably more destructive because of the churning and faster speed of the water.

How vulnerable is New Zealand to tsunamis?

Quite vulnerable. Tsunami hazard for the Pacific is higher than for other oceans because of the "Ring of Fire" - the zone of earthquakes associated with the tectonic plate boundary that bounds the Pacific. In New Zealand, scientists consider the tsunami hazard from two viewpoints - Pacific-wide events for which there will be some warning, and "near-source" tsunami generated by large offshore New Zealand earthquakes, landslides, and volcanic eruptions. The list of possible local tsunami sources is long. Because tsunami research is relatively young (compared to other geological hazards), the state of knowledge about the severity and frequency of local and distant tsunamis is poor. One of the main challenges facing tsunami researchers is that evidence of tsunamis does not stay in the landscape as it is eroded by natural processes. Impacts of past tsunami are therefore difficult to identify, unless someone was around and wrote about them at the time.

Does New Zealand have a tsunami warning system? If so, how does it work?

Aotearoa New Zealand has a warning system for tsunamis caused by distant earthquakes (such as in South America), and a warning system for tsunamis caused by local events.

For tsunamis coming to Aotearoa New Zealand from distant places – we receive a warning from the Pacific Tsunami Warning Centre in Hawaii. The National Emergency Management Agency (NEMA) is responsible for evaluating the danger to Aotearoa New Zealand, and issuing national or regional warnings. Tsunamis from South America, Alaska, and Japan, take more than 12 hours to reach New Zealand, giving authorities time to make decisions.

For tsunamis generated by local earthquakes – we have a monitoring system which uses a network of offshore DART buoys. Our analysts at the 24/7 National Geohazards Monitoring Centre use data from the buoys to help calculate the location of the earthquake and the likelihood of a tsunami happening along our coastlines. They notify NEMA who issue a tsunami warning if needed