Volcanologists estimate the material ejected in the Hunga Tonga-Hunga Ha’apai eruption was about twice that of the Mount St Helens eruption in 1980.

Powerful undersea volcano eruption in Tonga on Friday Jan 14, 2022. The latest eruption of the Hunga Tonga-Hunga Ha'apai volcano came just a few hours after Friday's tsunami warning was lifted. Hunga Tonga— Hunga Ha’apai erupting on 14 January – the day before an even more violent eruption. Photo: Tonga Geological Services/ EyePress News via AFP


GNS Science says initial assessments indicate that up to one cubic kilometre of material spewed from the Tongan volcano.

The eruption and gas plumes on 15 January rose about 30 kilometres into the sky.

In a statement, GNS Science Duty Vulcanologist Steve Sherburn said this eruption was the largest in the volcano’s current eruptive episode that dates back to 2009. He said it was much more violent than scientists had expected, given the volcano’s smaller eruptions in recent decades.

The atmospheric shockwave travelled around the globe and was picked up on air pressure sensors as far away as Iceland.

Sherburn said the eruption now holds the world record for being heard so far from the volcano.

Audible booming could be heard from New Zealand to the south and Alaska to the north.

“This was due to the low-frequency bass-like booms produced during the eruption that can travel thousands of kilometres away from the source,” Sherburn said.

He said the eruption was rare because it generated tsunami waves that impacted thousands of kilometres away from the volcano.

A volcanic-source tsunami such as this has not been seen since Krakatau erupted in Indonesia in 1883, he said.

Sherburn said the submarine eruption and tsunami is rare but not unprecedented and “scientists have been highlighting the possibility of submarine eruptions as tsunami sources for decades”.

Scientists expect that the volcano will remain active for weeks to months and the international community will continue to keep tabs on the volcano’s activity by monitoring satellite images.