New Zealand’s tectonic setting 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.
To improve tsunami monitoring for NZ and our neighbours, we have deployed the DART network in strategic areas in the Southwest Pacific. DART (Deep-ocean Assessment and Reporting of Tsunami) sensors 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.
Twelve sensors were deployed in stages (2019-21) at selected points close to the Hikurangi, Kermadec, Tonga and Vanuatu (formerly New Hebrides) trenches where they can detect and measure tsunami that could reach our shores in less than a few hours.
Just as important, the network also provide rapid information when no tsunami has been generated after a large earthquake or other possible trigger events such as under-sea landslides and volcanic eruptions.
The DART network consists of pairs of ocean bottom pressure sensors which record water height and surface buoys which transmit that data via satellite transmission to GNS Science. GNS Science’s 24/7 National Geohazards Monitoring Centre receives and analyses the data from the DART sensors. The centre then provides this information to the wider GNS science response teams, including the Tsunami Experts Panel (TEP), which analyses the data to generate scientific advice for the National Emergency Management Agency (NEMA). NEMA then uses this information to issue improved advisories and warnings to the public. Data from the network is streamed live to the Pacific Tsunami Warning and Mitigation System in Hawaii to enhance trans-Pacific forecasts, providing benefits to all countries surrounding the Pacific Ocean.
The network also provides monitoring and detection information for Tokelau, Niue, the Cook Islands, Tonga and Samoa. For more information on the DART sensors visit the NEMA page here.
The deployment of the DART network follows many years of work by GNS Science, NIWA and NEMA, and support from SAIC. Our scientists and partners designed the network and planned the locations of the DART sites to maximise the benefit to Aotearoa New Zealand and other countries in the Southwest Pacific. The DART Sensor Network is funded by MBIE and MFAT.
Only messages issued by the National Emergency Management Agency represent an official warning status for New Zealand. Go to here for the latest NEMA updates. For a local-source tsunami which can arrive in minutes, there is not enough time for an official warning, so it is important to recognise the natural warning signs and act quickly. Remember, LONG or STRONG, GET GONE. If there is earthquake shaking, drop, cover and hold. Protect yourself from the earthquake first, then act as soon as the shaking stops. If you are near the coast and experience any of the following: - Feel a strong earthquake that makes it hard to stand up, or a weak rolling earthquake that lasts a minute or more. - See a sudden rise or fall in water level. - Hear loud and unusual noises from the water.
Move immediately to the nearest high ground or as far inland as you can, out of tsunami evacuation zones. Do not wait for official warnings. Once you have evacuated, follow official advice from your local Civil Defence Emergency Management Group about when it is safe to return to tsunami evacuation zones. Do not return until an official all-clear message is given by Civil Defence Emergency Management. NEMA have a great website with information on what to do before, during and after a tsunami.