Remotely Operated Vessel Maps Tonga Caldera

Aerial view of the Hunga-Tonga Hunga-Ha’apai (HT-HH) volcano, showing new multibeam depth data overlaid on a satellite image of the islands (deep depths in blue, shallow depths in red).
SEA-KIT/NIWA-Nippon Foundation TESMaP survey team

As part of the Tonga Eruption Seabed Mapping Project, a robotic vessel has conducted a bathymetric survey of the Hunga Tonga-Hunga Ha‘apai volcano’s underwater caldera. Said volcano, you will recall, erupted spectacularly last January. The 12-metre vessel, USV Maxlimer, was controlled remotely from 16,000 km away, and carried sensors to measure the state of the seabed, temperature, salinity, turbidity, dissolved oxygen and chemical plumes. More at the press release. BBC News coverage.

Previously: The Rise and Fall of Hunga Tonga-Hunga Ha‘apai; Hunga Tonga-Hunga Ha‘apai, Before and After; How Satellites Revealed the Hunga-Tonga Hunga-Ha‘apai Eruption.

The Rise and Fall of Hunga Tonga-Hunga Ha‘apai

A storymap from Esri’s Robert Waterman, based on Maxar satellite imagery, shows the rise and fall of Hunga Tonga and Hunga Ha‘apai from being two separate islands before a 2015 eruption combined them, through its time as an apparently stable but awkwardly compound-named single island until it got blown apart last month.

Previously: Hunga Tonga-Hunga Ha‘apai, Before and After.

Hunga Tonga-Hunga Ha‘apai, Before and After

Two maps showing Hunga Tonga-Hunga Ha‘apai before and after the volcanic eruption of January 2022
NASA Earth Observatory/Joshua Stevens; data courtesy of Dan Slayback/NASA/GSFC.

NASA Earth Observatory has released digital elevation maps of Hunga Tonga-Hunga Ha‘apai both before and after the volcanic eruption earlier this month.

The digital elevation maps above and below show the dramatic changes at Hunga Tonga-Hunga Ha‘apai, the uppermost part of a large underwater volcano. It rises 1.8 kilometers (1.1 miles) from the seafloor, stretches 20 kilometers (12 miles) across, and is topped by a submarine caldera 5 kilometers in diameter. The island is part of the rim of the Hunga Caldera and was the only part of the edifice that stood above water.

Now all of the new land is gone, along with large chunks of the two older islands.