After a volcanic eruption, repairing Tonga’s only undersea internet cable could take two weeks

The effects of a colossal volcanic eruption in the Pacific archipelago of Tonga are still being calculatedbut one consequence is clear: Tonga was cut off from the internet, after the only undersea cable that connects the country to the rest of the web was damaged in the eruption.

Like many island nations, Tonga relies on a single undersea cable, the thickness of a garden hose and filled with fragile fiber optic filaments, to connect citizens. But on Tuesday, the government of Tonga said “International and domestic communications were disrupted due to damage to the undersea cable.”

The government added that “limited communication” was possible through satellite phones and high-frequency radio, but these constraints make it difficult to assess the damage caused by the January 14 eruption. The Tongan government has reported three deaths following a tsunami created by the volcano, which erupted on an uninhabited island.

According Reuters, the internet cable that connects Tonga to the web is 827 kilometers (514 miles) long and is secured via a relay on Fiji, Tonga’s second closest neighbour. The repair of the cable could take up to two weeks, as the work requires the intervention of a vessel specialized in the repair of submarine cables.

Undersea cables like this one, laid in the Kenyan port city of Mombasa, carry 99% of international internet traffic.
Credit: STRINGER/AFP via Getty Images

The nearest ship is the Reliance, owned by the American company SubCom. But he is currently moored some 4,700 kilometers (2,920 miles) in Papua New Guinea, and it will take days to get to Tonga. According to Craige Sloots, director of marketing and sales at Southern Cross Cable Network, a company that maintains a number of undersea cables in the region, that means repairing Tonga’s internet connection could take a total of two weeks.

“Its ability to repair would also predictably depend on any volcanic activity,” Sloots said. Reuters.

The incident is a stark demonstration of the fragility of the modern internet. Although we think of the web as a dense network with many redundancies, the truth is that it contains many single points of failure. In the West, this is most evident when huge web outages are caused by disruptions to centralized services like Amazon Web Services – an Amazon subsidiary that provides servers and computing power to the world’s biggest companies.

For countries like Tonga, however, submarine cables are a more obvious bottleneck. Currently, 99% of international Internet traffic passes through these submarine cables, with a valued 436 cables covering distances of 1.3 million kilometres. But while countries like the United States are served by multiple lines, poorer countries like Tonga have to rely on just one.

It should be noted that Tonga was in fact hit by a similar blackout in 2019and, therefore, signed a 15-year contract with a satellite internet company to guard against future failures. But according to a Z ratioDNetthe terms of the contract with the provider Kacific were disputed and as a result satellite connectivity was never activated.

Now Tongans have to wait for their internet to be fixed by hand. Such repairs are not unusual on a global scale – an undersea cable breaks about every two weeks – but they take time. Technicians from a specialist repair vessel will need to locate the fault in the Tonga cable by sending pulses of light down the line and timing how long it takes for the pulse to return. They will then have to navigate to the place of the breakage and, depending on the depth of the water, recover the cable using diving robots or grapples. The cable will then be brought to the surface and repaired by engineers on board the ship.