WELLINGTON, New Zealand – The tsunami threat around the Pacific from a giant underwater volcanic eruption began to recede on Sunday, while the extent of damage to Tonga remained unclear.
Satellite images showed that spectacular eruption That happened Saturday night as a cloud of ash, steam and gas mushroomed over the blue waters of the Pacific. A sonic boom could be heard as far away as Alaska.
In Tonga, it sent tsunami waves across the coast and people rushed to higher ground.
The outbreak cut the internet to Tonga, and friends and family members around the world anxiously tried to get in touch to find out if there were any casualties and the extent of the damage. Even government websites and other official sources remained without updates as of Sunday afternoon.
New Zealand Prime Minister Jacinda Ardern said there had not yet been any official reports of injuries or deaths in Tonga but warned authorities had not yet made contact with some coastal areas and smaller islands.
“Communications with Tonga remain very limited. And I know this is of great concern to the Tongan community here,” Ardern said.
She said there was significant damage to boats and businesses along the Tonga coast. The capital, Nuku’alofa, was covered in a thick layer of volcanic dust, Ardern said, contaminating water supplies and making fresh water a vital need.
Aid agencies said thick ash and smoke prompted authorities to urge people to wear masks and drink bottled water.
Ardern said New Zealand could not send a military surveillance flight over Tonga on Sunday because the ash plume was 63,000 feet high, but they hoped to send the flight on Monday, followed by support planes and naval vessels.
A complicating factor for any international relief effort is that Tonga has so far managed to avoid outbreaks of Covid-19. Ardern said New Zealand military personnel are fully vaccinated and ready to follow any protocols set out by Tonga.
Dave Snider, the tsunami warning coordinator at the National Tsunami Warning Center in Palmer, Alaska, said it is very unusual for a volcanic eruption to affect an entire ocean basin and the spectacle is both “humbling and frightening.”
The tsunami waves caused damage to boats in New Zealand and Santa Cruz, California, but did not appear to cause widespread damage. Snider said he expects the tsunami situation in the US and elsewhere to continue to improve.
Tsunami warnings were previously issued for Japan, Hawaii, Alaska and the US Pacific Coast. The US Geological Survey estimated that the eruption caused a magnitude 5.8 earthquake. Scientists said that tsunamis, which are generated by volcanoes rather than earthquakes, are relatively rare.
A tsunami warning has been issued for the entire archipelago, according to Tonga Meteorological Services, and data from the Pacific Tsunami Center said waves of 2.7 feet were detected.
Rachel Afeaki-Taumoepeau, chair of the New Zealand Tonga Business Council, said she hoped the relatively low level of the tsunami wave would have allowed most people to escape, although they are concerned for residents of those closest to the volcano situated islands. She said she has not yet been able to reach her friends and family in Tonga.
“We pray that the damage will only affect the infrastructure and people can get to the heights,” she said.
US Secretary of State Antony Blinken tweeted that he was “deeply concerned for the people of Tonga who are recovering from a volcanic eruption and tsunami. The United States stands ready to support our Pacific neighbors.”
Tonga gets its internet via an undersea cable from Suva, Fiji. All Internet connectivity to Tonga was lost around 6:40 p.m. local time, said Doug Madory, director of Internet analytics at network intelligence firm Kentik.
In Tonga, where about 105,000 people live, video posted to social media showed large waves washing ashore in coastal areas and swirling around houses, a church and other buildings. A Twitter user identified as Dr. Faka’iloatonga Taumoefolau posted video showing waves crashing ashore.
“Can literally hear the volcano erupting, sounds pretty intense,” he wrote, adding in a later post, “It’s raining ash and tiny pebbles, darkness covers the sky.”
The explosion of the Hunga Tonga Hunga Ha’apai volcano was the latest in a series of dramatic eruptions.
Earth imaging company Planet Labs PBC had been monitoring the island for the past few days after a new volcanic vent began erupting there in late December.
Satellite images taken by the company show how drastically the volcano has sculpted the area and created a growing island off Tonga.
“The island’s surface area appears to have increased by almost 45% due to the ash fall,” Planet Labs said days before the latest activity.
After Saturday’s outbreak, residents of Hawaii, Alaska and along the US Pacific Coast have been advised to move off shore to higher ground and follow directions from their local emergency management officers, Snider said.
“We don’t issue a recommendation for this stretch of shoreline, as we did — I’m not sure when that was the last time — but it’s really not an everyday experience,” Snider said.
Savannah Peterson watched in shock as the water in front of her oceanfront home in Pacifica, California, south of San Francisco, rose several feet in a matter of minutes.
“It came up so quickly and a few minutes later it was back down. It was crazy to see it go so fast,” she said. “I’ve never had water up to my front door, and today it was.”
Police rescued a surfer whose surfboard broke in strong waves off San Francisco.
Farther south in Santa Cruz, California, officials took stock of the damage after a flood damaged boats and swamped low-lying streets and parking lots, leaving cars afloat.
In Southern California, at least one boat sank in Ventura Harbor northwest of Los Angeles.
New Zealand’s private forecaster Weather Watch tweeted that people as far away as Southland, the country’s southernmost region, reported hearing sonic booms from the eruption. Others reported that many boats were damaged by a tsunami that hit a marina in Whangarei in the Northland region.
Earlier, the Matangi Tonga news site reported that scientists observed massive explosions, thunder and lightning near the volcano after it erupted early Friday. Satellite imagery showed a cloud 3 miles wide that rose to about 12 miles in the air.
Hunga Tonga Hunga Ha’apai Volcano is about 40 miles north of Nuku’alofa. In late 2014 and early 2015, a series of eruptions in the region created a small new island and disrupted international air traffic to the Pacific archipelago for several days.
There’s no significant difference between underwater and land-based volcanoes, and underwater volcanoes get bigger as they erupt, and eventually they usually erupt the surface, said Hans Schwaiger, a research geophysicist at the Alaska Volcano Observatory.
However, with underwater volcanoes, the water can increase the explosiveness of the eruption when it hits the lava, Schwaiger added.
There is generally an increase in small local earthquakes at the volcano before an explosion, but depending on how far it is from land, this may not be felt by residents along the coast, Schwaiger said.
In 2019, Tonga lost internet access for nearly two weeks when a fiber optic cable was severed. The director of the local cable company said at the time that a large ship may have cut the cable by pulling an anchor. Until limited satellite access was restored, people couldn’t even make international calls.
Southern Cross Cable Network’s Veverka said there were limited satellite connections between Tonga and other parts of the world, but he didn’t know if they could be affected by power outages.