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 were:
- Seafloor mapping
- Geological and ecological impacts from the eruption
- Eruption impacts on water column oceanography
View the report: Environmental impacts of the 2022 eruption of Hunga Tonga – Hunga Ha’apai: voyage report of part 1 of the TesMAP survey of the region in April-May 2022 (TAN2206) (PDF 14 MB)
The eruption
Hunga Tonga - Hunga Ha’apai, one of 22 volcanoes in the waters around the Tonga, erupted violently on 15thJanuary 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.
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.
2022 - Tonga post-eruption voyage
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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:
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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 - 1 May
Tangaroa is off the west coast of Tongatapu collecting seawater to analyse for trace metal. -
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 - 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 - 28 April
Tangaroa continues to map the area while deploying instruments to collect samples and capture images of the seafloor. -
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 - 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 - 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 - 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 - 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.