People have been forced to flee their homes in the Pacific island nation while streets and buildings have flooded, as tsunami waves crashed into Tonga’s main island of Tongatapu.
A tsunami advisory has now been issued for the west coast of the US, the National Weather Service’s tsunami warning centre has confirmed.
The alert covers areas stretching from southern California to Alaska and has also warned of 1-3ft waves along the Washington and Oregon coast.
An advisory means that strong currents and dangerous waves are imminent and people should stay out of the water.
New Zealand’s emergency management agency issued an advisory on tsunami activity for its north and east coasts stating that some parts of the nation could expect “strong and unusual currents and unpredictable surges at the shore following a large volcanic eruption”.
Meanwhile, New Zealand’s military said it was monitoring the situation and remained on standby. Australia’s federal government is also “monitoring the situation” and is “ready to provide support to Tonga if requested”.
But so far there have been no immediate reports of injuries or deaths in Tonga or elsewhere.
The eruption of Hunga Tonga-Hunga Ha’apai, about 65km north of capital Nuku’alofa, caused a tsunami measuring 1.2 metres, Australia’s meteorology bureau said.
On Friday, the volcano sent ash, steam and gas up to 20km into the air, Tonga Geological Services said in a Facebook post. It has a radius of 260km.
The Tonga Meteorological Services said a tsunami warning had been put in force for the whole nation and data from the Pacific tsunami warning centre showed waves of 80cm had been detected.
Authorities in the nearby island nations of Fiji and Samoa have also issued warnings, telling people to avoid the shoreline due to dangerous waves. The Japan Meteorological Agency said there may be some swelling of the water along Japanese coasts, but it is not expected to cause any damage.
Jese Tuisinu, a Fiji TV reporter, posted a video on Twitter showing large waves washing ashore, with people trying to flee from the oncoming waves in their cars.
“It is literally dark in parts of Tonga and people are rushing to safety following the eruption,” he said.
Tsunami waves measuring 2ft in height were also generated in American Samoa after the volcanic eruption.
In a statement, the Pacific tsunami warning centre in Honolulu said that “based on all available data, there is a threat to American Samoa of sea-level fluctuations and strong ocean currents that could be a hazard along beaches, in harbours and in coastal waters”.
A Tonga business news site reported that a convoy of police and military troops evacuated the island’s King Tupou VI from his palace near the shore, taking him to higher ground.
Can literally hear the volcano eruption, sounds pretty violent. pic.twitter.com/gX6z2lSJWf
— Dr Faka’iloatonga Taumoefolau (@sakakimoana) January 15, 2022
Professor of volcanology at the University of Auckland, Shane Cronin, said the eruption is one of the volcano’s largest since 1100AD and warned that the people of Tonga should be vigilant of further eruptions of the same size.
“The past large Hunga eruptions were comparable to the scale that we have seen in the 15 January 2022 event or larger,” he said. “Based on these past events, tephra [ash] falls of up to 20cm thick can be expected on Tongatapu and the Ha’apai group of islands.
“Geological deposits on Hunga Ha’apai of the AD1000 and AD200 eruptions suggest that there were many eruptive phases during each of the major eruption episodes.”
He added: “This suggests that the current eruption episode could last several weeks or months and that further similar-sized eruptions to the 15 January 2022 event are possible.”
A Twitter user identified as Dr Faka’iloatonga Taumoefolau posted a video showing waves crashing ashore. “Can literally hear the volcano eruption, sounds pretty violent,” he wrote.
In a later tweet, he added: “Raining ash and tiny pebbles, darkness blanketing the sky.”
In late 2014 and early 2015, a series of eruptions in the area created a small new island and disrupted international air travel to the Pacific archipelago for several days.