WELLINGTON, New Zealand — New Zealand and Australia were able to send military surveillance flights to Tonga on Monday to assess the damage a huge undersea volcanic eruption left in the Pacific island nation.
A towering ash cloud since Saturday’s eruption had prevented earlier flights. New Zealand hopes to send essential supplies, including much-needed drinking water, on a military transport plane later Monday.
Communications with Tonga remained extremely limited. The company that owns the single underwater communications cable that connects the island nation to the rest of the world said it likely was severed in the eruption and repairs could take weeks.
The loss of the cable leaves most Tongans unable to use the internet or make phone calls abroad. Those that have managed to get messages out described their country as looking like a moonscape as they began cleaning up from the tsunami waves and volcanic ash fall.
Tsunami waves of about 80 centimeters (2.7 feet) crashed into Tonga’s shoreline, and New Zealand Prime Minister Jacinda Ardern described damage to boats and coastal shops.
Scientists said they didn’t think the eruption would have a significant impact on the Earth’s climate.
Huge volcanic eruptions can sometimes cause temporary global cooling as sulfur dioxide is pumped into the stratosphere. But in the case of the Tonga eruption, initial satellite measurements indicated the amount of sulfur dioxide released would only have a tiny effect of perhaps 0.01 Celsius (0.02 Fahrenheit) global average cooling, said Alan Robock, a professor at Rutgers University.
Satellite images showed the spectacular undersea eruption Saturday evening, with a plume of ash, steam and gas rising like a giant mushroom above the South Pacific waters.
A sonic boom could be heard as far away as Alaska and sent pressure shockwaves around the planet twice, altering atmospheric pressure that may have briefly helped clear out the fog in Seattle, according to the National Weather Service. Large waves were detected as far as the Caribbean due to pressure changes generated by the eruption.
Samiuela Fonua, who chairs the board at Tonga Cable Ltd. which owns the single cable that connects Tonga to the outside world via Fiji, said the cable appeared to have been severed about 10 to 15 minutes after the eruption. He said the cable lies atop and within coral reef, which can be sharp.
Fonua said a ship would need to pull up the cable to assess the damage and then crews would need to fix it. A single break might take a week to repair, he said, while multiple breaks could take up to three weeks. He added that it was unclear yet when it would be safe for a ship to venture near the undersea volcano to undertake the work.
A second undersea cable that connects the islands within Tonga also appeared to have been severed, Fonua said. However, a local phone network was working, allowing Tongans to call each other. But he said the lingering ash cloud was continuing to make even satellite phone calls abroad difficult.
He said Tonga had been in discussions with New Zealand about getting a second outside communications cable to ensure a more robust network but the nation’s isolated location made any solution difficult.
Ardern said the capital, Nuku’alofa, was covered in a thick film of volcanic dust, contaminating water supplies and making fresh water a vital need.
Aid agencies said thick ash and smoke had prompted authorities to ask people to wear masks and drink bottled water.
In a video posted on Facebook, Nightingale Filihia was sheltering at her family’s home from a rain of volcanic ash and tiny pieces of rock that turned the sky pitch black.
“It’s really bad. They told us to stay indoors and cover our doors and windows because it’s dangerous,” she said. “I felt sorry for the people. Everyone just froze when the explosion happened. We rushed home.” Outside the house, people were seen carrying umbrellas for protection.
Ardern said New Zealand was unable to send a surveillance flight over Tonga on Sunday because the ash cloud was 63,000 feet (19,000 meters) high.
One complicating factor to any international aid effort is that Tonga has so far managed to avoid any outbreaks of COVID-19. Ardern said New Zealand’s military staff were all fully vaccinated and willing to follow any protocols established by Tonga.
Dave Snider, the tsunami warning coordinator for the National Tsunami Warning Center in Palmer, Alaska, said it was very unusual for a volcanic eruption to affect an entire ocean basin, and the spectacle was both “humbling and scary.”
The U.S. Geological Survey estimated the eruption caused the equivalent of a magnitude 5.8 earthquake. Scientists said tsunamis generated by volcanoes rather than earthquakes are relatively rare.
Rachel Afeaki-Taumoepeau, who chairs the New Zealand Tonga Business Council, said she hoped the relatively low level of the tsunami waves would have allowed most people to get to safety, although she worried about those living on islands closest to the volcano. She said she hadn’t yet been able to contact her friends and family in Tonga.
“We are praying that the damage is just to infrastructure and people were able to get to higher land,” she said.
Tonga gets its internet via an undersea cable from Suva, Fiji. All internet connectivity with Tonga was lost at about 6:40 p.m. local time Saturday, said Doug Madory, director of internet analysis for the network intelligence firm Kentik.
On Tonga, which is home to about 105,000 people, video posted to social media showed large waves washing ashore in coastal areas and swirling around homes, 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 eruption, sounds pretty violent,” he wrote, adding in a later post: “Raining ash and tiny pebbles, darkness blanketing the sky.”
The explosion of the Hunga Tonga Hunga Ha’apai volcano, about 64 kilometers (40 miles) north of Nuku’alofa, was the latest in a series of dramatic eruptions. In late 2014 and early 2015, eruptions created a small new island and disrupted international air travel to the Pacific archipelago for several days.
Earth imaging company Planet Labs PBC had watched the island in recent days after a new volcanic vent began erupting in late December. Satellite images showed how drastically the volcano had shaped the area, creating a growing island off Tonga.
“The surface area of the island appears to have expanded by nearly 45% due to ashfall,” Planet Labs said days before the latest activity.
It’s too early to tell how much ash was produced by the eruption because the volcanic cloud included vapor resulting from sea water interacting with the hot magma, experts said.
The eruption in shallow water may be similar to a series of eruptions between 2016 and 2017 that shaped Bogoslof Island north of the Aleutian Islands, said Michelle Coombs, a scientist at the U.S. Geological Survey’s Alaska Volcano Observatory.
“When it erupts in shallow sea water, that interaction between hot magma and sea water adds extra energy to the explosion and creates taller and bigger ash clouds,” Coombs said.
The ash cloud was drifting westward and aircrafts will be likely diverted around its periphery as a precaution, said Scott Bachmeier, a research meteorologist at the University of Wisconsin-Madison.
Associated Press Science Writer Seth Borenstein contributed to this report from Kensington, Maryland.