The volcanic eruption severed Tonga’s internet connection, and repairs won’t be easy

The sole cable linking Tonga to the global internet backbone in the South Pacific was broken after the eruption.
diver examines underwater cable in pacific
Assessing and mending undersea cables is difficult even without a volcanic eruption in the background. U.S. Pacific Fleet / Flickr

Over the weekend, Tonga’s Hunga Tonga-Hunga Ha‘apai volcano erupted, pouring plumes of smoke into the atmosphere and hurtling tsunami waves across the ocean.

The eruption was violent, and the extent of damages incurred in the messy aftermath that followed has not been fully determined. 

The cataclysmic event also splintered the sole undersea telecommunication cable adjoining Tonga’s islands to the outside world, causing a sweeping internet blackout. Cloudflare showed internet traffic from the country “plunged to near-nothing around 5:30 p.m. local time on January 15,” MIT Technology Review reported. 

An official statement the government of Tonga made on Twitter indicated that “limited communication has been made with Vava’u and Ha’apai through satellite phones and HF [high frequency] radio,” and two communications operators were “working on satellite options to restore some services including the internet” as they figure out how to reinstate full communications. In the meantime, international calls and messages will be prioritized, while domestic communications will be limited. 

It’s probable that cable repair is lower down on the to-do list as the country manages more urgent emergencies, like public health and access to food and water. 

[Related: Tonga is fighting multiple disasters after a historic volcanic explosion]

Reuters reported that the severing of this main line of communication could cut Tonga off from the rest of the world for days, or even weeks. And satellite phone signals remain patchy due to the cloud of ash cloaking the archipelago. Tonga’s 514-mile-long cable to Fiji will likely lie frayed on the seafloor awaiting the arrival of a specialized ship, last moored at Port Moresby, Papua New Guinea a day ago, according to Reuters.

These crucial but unseen fiber optic cables can carry about 200 times more data than a satellite, and form the backbone of the global internet. But they’re expensive to install and difficult to maintain—fixing broken undersea cables is tricky business. According to Reuters, operators first have to find the fracture in the line by assessing the bounce back on a pulse of light sent down the cable. When engineers locate the breakage point, they have to dispatch either a submersible or deep water hook to retrieve the cable and bring it up to the surface for repairs. So far, analysts have said that the break seemed to be about 23 miles off the coast of Nuku’alofa, Tonga’s capital. The New York Times said that repairs could cost hundreds of thousands of dollars on top of the expenses for operating specialty ships. 

[Related: An undersea cable could bring speedy internet to Antarctica]

Samiuela Fonua, the chairperson of the state-owned Tonga Cable Ltd that operates the line, told The Guardian that they intend to start mending the line sometime next week. However, he told that outlet he was concerned about continuing volcanic activity obstructing the passage of incoming repair ships. 

This is not the first time Tonga has experienced an internet interruption caused by disturbed seabed cables, MIT Tech Review reported. The South Pacific country had a week-long internet blackout in 2019 when an undersea cable was reportedly pierced by an anchor dropped from a Turkish-flagged ship. Back then, the island used satellite communications to tide it over the repair period.