Tsunami monitoring and detection network
This page provides information about New Zealand’s tsunami monitoring and detection network.
In 2019, the New Zealand Government deployed a Deep-ocean Assessment and Reporting of Tsunami (DART) buoys. This gave a significant boost to New Zealand’s end to end arrangements for monitoring, detecting and issuing warnings about tsunami.
New Zealand’s geographical and geological place in the Pacific, puts us at risk from many different tsunami sources, some may be generated and arrive at our nearest coasts in less than an hour.
The network includes a number of DART stations, which can provide rapid confirmation if a tsunami has been generated, and will enable timelier, more accurate warnings of tsunami using public alerting systems like Emergency Mobile Alerts.
What is a DART station?
DART (Deep-ocean Assessment and Reporting of Tsunami) stations are deep-ocean instruments that monitor changes in sea level. They are currently the only accurate way to rapidly confirm a tsunami has been generated before it reaches the coast.
This is about keeping people safe by giving advance notice that a tsunami is heading our way. This is particularly critical for unfelt earthquakes originating from the Kermadec trench or further afield. Early detection of a tsunami using the DART network allows us to accurately provide early warnings using a range of communication channels including Emergency Mobile Alerts.
How does the DART network work?
The DART network detects tsunami threats by measuring associated changes in water pressure via sea floor sensors. They are capable of measuring sea-level changes of less than a millimetre in the deep ocean. Two-way communication between the DART network and a 24/7 monitoring centre allows rapid assessment and subsequent warning advice to be provided to the public.
End to end process from seafloor to tsunami warning
- An event that could trigger a tsunami such as a large undersea earthquake or undersea volcanic eruption occurs.
- If a tsunami is generated, there are rapid and unusual changes in the water pressure.
- The DART stations’s sea floor sensor detects water pressure changes.
- The measurements are sent by acoustic signal to the surface.
- The DART station sends the signal to a satellite.
- The signal is sent to the 24/7 National Geohazards Monitoring Centre at GNS Science.
- GNS Science Geohazards Analysts analyse the data.
- If a tsunami has been detected the Geohazard Analyst will notify the National Emergency Management Agency, the official tsunami warning agency for New Zealand.
- The National Emergency Management Agency will issue a tsunami warning to CDEM Groups, emergency services, media and directly to the public via their website www.civildefence.govt.nz.
- If flooding of land areas is expected, the National Emergency Management Agency will also send an Emergency Mobile Alert to all capable mobile phones in the affected areas.
Get tsunami ready: Know the natural warning signs and take action
For a local source tsunami, which could arrive in minutes, there won’t be time for an official warning. It is important to recognise the natural warning signs and act quickly.
If you are near a shore and experience any of the following, take action. Do not wait for official warnings.
- Feel a strong earthquake that makes it hard to stand or a long earthquake that lasts more than a minute
- See a sudden rise or fall in sea level
- Hear loud or unusual noises from the sea
Drop, Cover and Hold during the shaking. Protect yourself from the earthquake first.
As soon as the shaking stops, move immediately to the nearest high ground, out of all tsunami evacuation zones, or as far inland as you can.
Remember: Long or Strong, Get Gone.