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2022 - Tonga post-eruption

NIWA is leading a voyage (TAN2206), between 9th April and 6th May 2022 to Hunga Tonga - Hunga Ha’apai (HT-HH) volcano within the Kingdom of Tonga.

Subsequent to a recent eruption at HT-HH, this voyage is intended to identify changes in the seafloor and allow the ongoing recovery of the seabed and associated ecosystems to be assessed.

The three main research themes are:

  • Seafloor mapping
  • Geological and ecological impacts from the eruption
  • Eruption impacts on water column oceanography.

The eruption

Hunga Tonga - Hunga Ha’apai, one of 22 volcanoes in the waters around the Tonga, erupted violently on 15th January 2022. This eruption was the largest of three volcanic events in the last decade. Prior to the eruption the volcano caldera sat approximately 150 m below sea level and part of the volcano connected the islands of Hunga Tonga and Hunga Ha'apai making them a single landmass. Following the eruption, no part of the volcano is now above water and the islands of Hunga Tonga and Hunga Ha'apai were reduced in size. It is expected similarly dramatic changes have occurred in the underwater topography. Submarine cable breakages show impacts up to 50 km from the volcano caldera, implying changes to the seabed over an area of at least 8,000 km2.

Meet our staff

Here are short profiles of some of the amazing people on board.

Mapping the Tongan eruption

The January eruption of the Tongan volcano Hunga Tonga – Hunga Ha’apai triggered tsunamis as far away as the Caribbean. NIWA scientists are onboard RV Tangaroa surveying the ocean around the volcano, working to understand the largest eruption of its kind since 1981 so they can help increase our knowledge about similar volcanoes around the world.

The instruments at work - In the volcano's wake

Our team onboard RV Tangaroa are equipped with all the tech and tools they need to explore the undersea changes caused by the devastating volcanic eruption in Tonga earlier this year.

Check out these voyage updates:

Voyage update - 2 May

Tangaroa has sampled more clean seawater from a site not affected by the January 15th eruption of Hunga Tonga-Hunga Ha’apai (HT-HH).

Voyage update - 30 April

RV Tangaroa has just completed its last full day of sampling around the waters of Hunga Tonga-Hunga Ha’apai (HT-HH).

Voyage update - 28 April

Tangaroa continues to map the area while deploying instruments to collect samples and capture images of the seafloor.

Voyage update - 26 April

Over the last 24 hours, we have gone from the deep seafloor at 2,300 m to the shallow slopes of the island of Tongatapu, located to the south-east of the volcano.

Voyage update - 24 April

We have sampled 11 stations today, with different pieces of equipment, starting with rock dredges on a ridge close to Hunga Ha’apai. The samples taken returned a trove of rock specimens that got the geologist onboard excited.

Voyage update - 22 April

Tangaroa arrived at its next site located 70 km south-west of the caldera. In 2,350 m of water, it is one of the sites used to measure the thickness and composition of the eruptive material deposited on the seafloor.

Voyage update - 20 April

Today was a busy day on board RV Tangaroa, as we finished sampling at the site where the Tongan domestic communications cable broke over a distance of many kilometres during the Jan 15th 2022 Hunga Tonga - Hunga Ha’apai volcano (HT-HH) eruption.

Voyage update - 17 April

Samples are collected to understand how the seafloor geology, biogeochemistry and ecosystem health has been affected by the volcanic eruption.

Voyage update - 1 May

Tangaroa is off the west coast of Tongatapu collecting seawater to analyse for trace metal.

Voyage update - 29 April

Tangaroa is now 100 km south-west of Hunga Tonga - Hunga Ha’apai volcano (HT-HH), surveying in 2,440 m of water in the Lau Trough.

Voyage update - 27 April

We started the day by examining the seafloor towards the main island of Tongatapu. As we got closer, the images from the seafloor clearly showed a layer of ash several centimetres thick overlaying the white bedrock of the main Tongan islands.

Voyage update - 25 April

We sampled along an erosion channel that was mapped previously in 2016, showing this channel has deepened since then.

Voyage update - 23 April

Tangaroa has just arrived north of the volcano to deploy the glider. The launch was successful and, after some shallow test dives, the instrument was sent on its first transect.

Voyage update - 21 April

The crew of RV Tangaroa continues to map the seafloor on the deep northern and western slopes of the volcano, with the aim of identifying areas of morphological change of the seafloor caused by the January 15th eruption.

Voyage update - 18 April

RV Tangaroa completed its transit to the sampling site, CABLE BREAK WEST which lies at a depth of 1,920 m.

Media release - 1 April

NIWA and The Nippon Foundation are undertaking a mission to discover the undersea impacts of the recent Tongan volcanic eruption.

Map of the course of RV Tangaroa taken during the TAN2206 voyage starting on 9 April 2022

Select anywhere on the red track to see position details and time as well as other vessel information. N.B. Dates and times are in Coordinated Universal Time (UTC). New Zealand Standard Time (NZST) is 12 hours ahead of UTC. Click on the ship icons for points of interest during the voyage.