A look at Tonga's internet blackout following the volcano blast, which initial investigations suggest destroyed the country's single undersea internet cable
a volcanic eruption broke it Isobel Asher Hamilton / Insider : Tonga's volcanic eruption ruptured a giant undersea internet cable and knocked the country's internet offline João Tomé / The Cloudflare Blog : Tonga's likely lengthy Internet outage TNW : The Tonga volcanic disaster shows we need to rethink telecom infrastructure Tweets: Abdullahi Halakhe / @qulshtm : “One of the reasons why we're only getting a first glimpse of the damage in Tonga is because “the undersea cable connecting its internet to the rest of the world has been destroyed by the blast.” https://www.technologyreview.com/ ... @SeweS_ @mmnjug Niall Firth / @niallfirth : Tonga's main subsea cable that connects it to the outside world has been damaged. That's making it harder to coordinate aid efforts and find out what's happening on the ground. I wanted to know how it could get back online. @stokel found out for me. https://www.technologyreview.com/ ...
Context & Ripple Effects
When the Hunga Tonga eruption severed the country's sole submarine link to the global internet, the outage was total because there was no second path — a vulnerability later book-length retrospectives still treat as the defining case study of single-cable island connectivity.
The failure mode is not exotic: research shows most cable faults come from mundane causes like anchors and fishing gear, with repairs running into the millions per incident, and recent multi-cable breaks off West Africa and Vietnam show even countries with several cables can lose most of their international capacity at once.
First-order effects
- Tonga's population loses internet access entirely — not degraded service — because the country depended on one cable for all international traffic, leaving satellite links as the only workaround.
Second-order effects
- Repair logistics become the bottleneck: as the West Africa incidents showed, mobilizing a cable ship and splicing fiber takes weeks, so island nations must negotiate priority access to a small pool of repair vessels.
Third-order effects
- If single points of failure keep producing national blackouts, small island states face pressure to fund redundant landings or satellite backhaul — the same resilience calculus now visible in multi-cable markets like Vietnam's, where three of five cables going down still caused major disruption.
The trend: National internet resilience is shifting from assuming any one cable will survive to engineering for simultaneous loss of multiple paths, whether from volcanoes, anchors, or canyons.