Invisible natural forces at work

New tsunami detection technology for Southwest Pacific

Natural Hazards and Risk

Back in 2009 a very complicated 8.1 magnitude earthquake happened in the southern Pacific Ocean. It generated a tsunami in Samoa and Tonga that travelled across most of the Southwest Pacific. Nearly 200 people lost their lives.

This is one of the types of earthquakes we are trying to capture with a new network of deep ocean tsunami sensors being deployed to the north and east of Aotearoa New Zealand, says Dr Bill Fry from GNS Science.

We will get improved warning of tsunamis generated in the Southwest Pacific thanks to these sensors. Nine have already been deployed and the remaining three are scheduled to be in place in the next 12 months. The buoys are part of a $47.3 million government-funded network.

GNS Science and NIWA are providing specialist input into the initiative, led by the National Emergency Management Agency (NEMA). Our science experts designed the network by planning the locations of the buoys to maximise benefit to Aotearoa New Zealand and other countries in the Southwest Pacific.

The new network represents the biggest single growth in tsunami monitoring in this part of the Pacific region in decades, says Dr Fry.

“The best way to quickly forecast tsunami impacts and reduce the effects on people and property is through analysis of a combination of data from earthquake instruments and the DART buoys.”

DART stands for Deep-ocean Assessment and Reporting of Tsunami. The DART buoys are being deployed at selected points adjacent to the Hikurangi, Kermadec, Tonga, and New Hebrides trenches where they will be able to detect and measure tsunamis that could reach our shores in less than two hours.

The instruments are fourth generation DART buoys with more advanced sensors, and better software and power management systems than earlier models.

“This gives us enhanced ability to detect and measure tsunamis generated by earthquakes or other sources, thus giving better and faster information to our scientists and to agencies that disseminate warnings and advisories to the community” says Dr Fry.

GNS Science’s 24/7 National Geohazards Monitoring Centre /Te Puna Mōrearea i te Rū will receive data from the buoys. Then it will be analysed by our science team and the national tsunami experts panel. This analysis will underpin the delivery of advice to NEMA, which will issue advisories and warnings to the public. The network will also provide monitoring and detection information for Pacific Island countries including Tokelau, Niue, the Cook Islands, Tonga and Samoa.

Dr Fry says data from the network will be streamed live to the Pacific Tsunami Warning Center to enhance trans-Pacific forecasts, providing benefits to all countries surrounding the Pacific Ocean.

“The new deep-sea array will enable better warnings and provide more accurate estimates of how big the waves could be when they reach our coasts. The sensors are particularly valuable for monitoring potential tsunamis from earthquakes in the Southwest Pacific that may be unfelt on the mainland of Aotearoa New Zealand.”

DART buoys are currently the only way to rapidly confirm a tsunami has been generated before it reaches the coast. They will 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.

We are also using resources from a newly-funded, 5-year Endeavour research programme to push the boundaries of what the DART array can deliver to help keep Aotearoa New Zealand safe from regional tsunamis.

Remember – if it’s long or strong, get gone!

“The establishment of the DART Buoy network is a significant boost to New Zealand’s end-to-end arrangements for monitoring, detecting and issuing warnings about tsunami threats. The network will help keep people safe by enabling faster detection and more accurate warnings of tsunami threats.”
Sarah Stuart-Black, Director, Civil Defence and Emergency Management

NZ DART buoys – tsunami detection technology

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Image credit: Sarah Searson, NIWA

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