Pacific

Tonga: Tsunami warning lifted but volcano still monitored

12:25 pm on 15 January 2022

The tsunami marine warning issued for all of Tonga waters following the violent eruptions of underwater volcano Hunga-Tonga-Hunga-Ha'apai has been lifted.

Hunga-Tonga-Hunga-Ha'apai erupted on Friday sending ash, steam and gas 20 kilometres into the air.

Tonga's Geological Services went out to the site on Friday, January 15, 2022 Photo: Tonga Geological Services

The volcano had been active from 20 December 2021 but was declared dormant on 11 January.

Hunga-Tonga-Hunga-Ha'apai underwater volcano on January 15, 2022 Photo: Tonga Geological Services

The head of Tonga Geological Services, Taaniela Kula, told RNZ Pacific that at 4am on Friday 15 January, an eruption was picked up on satellite.

Kula said the eruption on Friday was almost seven times bigger than the one on 20 December, bigger in terms of the radius of the plume that was scattered from the volcano, up to 250km away from the volcano radius.

He said his team visited the site on Friday to see up close, 2-3km away from the volcano, and the eruption of ash really shot up to over 1km into the atmosphere.

"That created an ash column of about 5km diameter just elevating ash up to 20kms into the atmosphere, that was really high, and the plume covered that 5km diameter of that island."

Kula said it appeared to have been sourced from two locations but "we couldn't identify on Friday because of too much plume and the source was not clear but his team could see multiple shooting ... and ash".

He said it was the biggest eruption he has seen on the site.

Overnight, Kula said they noted that the lack of ash emerging into the atmosphere and the satellite picked up ash was drifting to the east and dispersed after, around 2am. It had gone past 'Otu Mu'omu'a islands of Ha'apai to the East side.

"This morning, steam and gas plume coming out of the volcano, drifting Eastwards, and so they have lowered the aviation colour code from 'Red' to 'Orange' this morning because of no sign of ash."

Kula said a lot of ash was noticed in the Ha'apai group and this morning a navy boat is shipping out drinking water to locals.

The Tonga Geological Services said people were told to disconnect their water supplies on Friday and to ensure that's no ashfall on their rainwater harvesting system, especially their roof and also their gutter system before they reconnect it.