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Tsunami Monitoring

Tsunami monitoring

Detecting and recording tsunamis

  • Detecting tsunamis.
    There is a network of deep ocean tsunami sensors (DART buoys) to the north of Aotearoa New Zealand. This helps detect potential tsunami-generating earthquakes in the Southwest Pacific.
  • Recording a tsunami.
     Tsunami gauges are located around the coast of Aotearoa New Zealand to confirm the occurrence of a tsunami and record its characteristics. The GeoNet website has the latest tsunami gauge recordings for operational instruments in the region.

How Aotearoa New Zealand’s tsunami warning system will work

1 An event occurs that could trigger a tsunami, such as a large undersea earthquake or undersea volcanic eruption. 2 - If a tsunami is generated, there are rapid and unusual changes to water pressure on the sea floor. 3- The DART buoy’s sensor on the sea floor measures water pressure. 4 The measurements are sent by acoustic signal to a buoy on the surface. 5 The buoy sends the signal to a satellite. 6 The signal is sent to the 24/7 National Geohazards Monitoring Centre at GNS Science. 7 GNS Science geohazards analysts examine the data. 8 If a tsunami has been detected the geohazard analysts notify the National Emergency Management Agency (NEMA), the official tsunami warning agency for New Zealand. 9 NEMA issues a tsunami warning to Civil Defence and Emergency Management Groups, emergency services, media and directly to the public via their website and Twitter. 10 If flooding of land areas is expected, NEMA also sends an Emergency Mobile Alert to all capable mobile phones in the affected areas.

DART buoy network

Dart Buoy 1

DART (Deep-ocean Assessment and Reporting of Tsunami) buoys are deep-ocean instruments that monitor changes in sea level.

Twelve buoys are being deployed in stages (2019-21) at selected points adjacent to the Hikurangi, Kermadec, Tonga and South New Hebrides trenches where they can detect tsunamis that could reach our shores in less than two hours.

Improved resilience from tsunamis

The array of DART buoys enables better warnings by delivering data to help GNS Science provide more accurate estimates on how big the waves could be if they reach our coast. The sensors are particularly valuable for monitoring potential tsunamis from earthquakes in the Southwest Pacific that may be unfelt on the New Zealand mainland. The network provides monitoring and detection information for Tokelau, Niue, the Cook Islands, Tonga and Samoa.

Just as important, the buoys 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.

Data analysis

Dart Buoy 2

GNS Science’s 24/7 National Geohazard Monitoring Centre will receive and analyse data from the DART buoys. The Centre will then provide information and analysis to the National Emergency Management Agency (NEMA) which will issue advisories and warnings to the public. Data from the network is streamed live to the Pacific Tsunami Warning System in Hawaii to enhance trans-Pacific forecasts, providing benefits to all countries surrounding the Pacific Ocean.

Our science contribution

The deployment of the DART buoys follows many years of work. Working with NEMA, we recognised a way to improve tsunami resilience in Aotearoa New Zealand. Together GNS Science and NIWA provided specialist input.

We used our science to quantify the hazard and design a solution. Our scientists designed the network, planning the locations of the DART buoys to maximise benefit to Aotearoa New Zealand and other countries in the Southwest Pacific. We partnered with MFAT and NEMA to deliver the solution.

The DART buoys are part of a $47.3 million government-funded network. Partners in the project include GNS Science, NIWA, NEMA, MFAT and MBIE.

Learn more about tsunami monitoring

Photos: Supplied by NIWA