As in many remote Pacific nations, the island kingdom of Tonga is connected to the world by a single cable, roughly the width of a garden hose, that carries hair-thin optic fibers across a vast ocean bed.
That lone conduit is the means by which Siniva Filise, who lives in Wales and is part of the large Tongan diaspora, starts each day with a video call from her mother 10,000 miles away. “She’s like the alarm — she doesn’t care what time it is,” Ms. Filise said. “She’ll just call.”
But for the past four days, the phone has been silent. Tonga’s undersea cable was severed by a huge volcanic eruption on Saturday night, and the country now faces weeks of digital darkness as a repair ship prepares to make its way from Papua New Guinea.
The ship is not expected to reach Tonga until Feb. 1, after a voyage of more than eight days. Then it will perform the difficult task of retrieving two sections of damaged cable from the ocean floor and splicing in replacements, with the threat of further volcanic activity ever-present.
In the meantime, the only word about Tonga’s immediate needs after last week’s eruption and subsequent tsunami has come through the country’s few satellite phones. The Red Cross said on Wednesday that drinking water supplies had been severely affected by ash and saltwater, and two New Zealand Navy vessels were set to arrive on Friday with large stores of water. Tonga’s main airport remained inoperable as workers tried to remove ash from a runway.
On Tuesday night, the government in Tonga offered its first update on the situation there, saying that the death toll stood at three and that evacuations were underway from outlying islands, where a number of homes were destroyed or damaged.
The undersea cable that connects Tonga to the global internet went live in 2013 and runs between it and Fiji, which lies about 500 miles northwest.
Cable connections in such lightly populated places — Tonga has about 100,000 people — are known as thin routes, where the return on investment is seldom high enough to attract investors. The World Bank Group and the Asian Development Bank financed Tonga’s cable.
More than 430 cables like the one serving Tonga sit on the beds of the earth’s oceans, covering almost a million miles in total. It is basically internet plumbing, and like all plumbing, it can suffer ruptures.
A few minutes after the volcanic blast on Saturday night, there was a plunge in internet traffic to Tonga. A little over an hour later, the connection went completely dark, said Doug Madory, the director of internet analysis at Kentik, a network monitoring company. “I think that’s the moment when something reached the cable,” Mr. Madory said.
The following day, the cable went into what is known as single-end feed mode, in which it was being powered from Fiji but not from Tonga, said Craige Sloots, a spokesman for Southern Cross Cable Network, which is part of the collective working to repair the connection.
Analysts have identified a break both in the international section of Tonga’s cable, which occurred about 23 miles off the coast of its capital, Nuku’alofa, and in the islands’ internal network. The cause is believed to be a land slippage or shift in the sea floor, Mr. Sloots said in an email.
Under any circumstances, fixing this internet plumbing is intricate work. Add in the complications of an active volcano and the tentacle-like effects of the coronavirus pandemic, and it is even more challenging, said Amanda Watson, a researcher at the Australian National University’s Department of Pacific Affairs.
“One of the key issues is that there are very few vessels that are equipped to lay and repair undersea cables,” she said.
Repairs may ultimately cost hundreds of thousands of dollars, with daily costs for the ship tasked with fixing the cable, the CS Reliance, at between $35,000 and $50,000. SubCom, the company responsible for the repair, has estimated that it will take at least four weeks to restore the connection, according to New Zealand’s Foreign Ministry.
The work on each break, when it happens, will begin by dragging two grapnels — a kind of anchor with several hooks — along the ocean floor, to find the severed ends of the cable, which may have been pushed several miles apart.
The two ends will then be hoisted aboard the ship, a hulking vessel more than 150 yards long. Finally, in a special clean room on board, the damaged parts will be cut out and a replacement cable will be spliced in.
Up to 50 people may be aboard to assist in the repair, said Dean Veverka, the director of the International Cable Protection Committee, a nonprofit organization based in Britain. “It’s quite a task to recover the cable up onto the ship,” he said.
As the repair ship prepared to leave Papua New Guinea, the Hunga-Tonga-Hunga-Ha’apai volcano — which exploded Saturday night in what was believed to be the world’s largest volcanic eruption in three decades — continued to rumble.
With no monitoring equipment nearby, volcanologists are relying on observations on the ground or satellite images to try to predict the volcano’s next moves. The ash clouds obscuring the island that is home to the undersea volcano, about 40 miles from the Tongan capital, make those efforts even more difficult.
Tonga sits due west of one of the world’s deepest ocean trenches, where the Pacific plate is diving under both the Kermadec and Tonga plates. The rate collision between the plates is extremely high, producing a chain of an estimated 30 volcanoes, of which Hunga-Tonga-Hunga-Ha’apai is one.
Possible outcomes range from a quieting down of the volcano to successive explosive eruptions, which could trigger further tsunamis, said Shane Cronin, a professor of earth sciences at the University of Auckland in New Zealand.
“This is all very speculative, because we have no seismometers nearby,” he said. “A lot of our knowledge about the volcanic activity is all reactionary — we don’t have any forecasting capabilities, with no seismic stations working there and no other instrumentation at all. It’s very frustrating.”
In the interim, the sudden spotlight on the often-overlooked South Pacific is drawing attention to its remoteness, and the challenges that come with that.
“It’s been a useful process of trying to highlight the practical issues in terms of communications infrastructure in the region,” said Dr. Watson, of the Australian National University.
For those anxiously awaiting the familiar ding of a WhatsApp message, the distance is more apparent than ever. “I’m sure I’m the same as every Tongan around the world,” Ms. Filise said. “Just waiting, and hoping for news.”
Damien Cave contributed reporting.