The Day Tonga Lost the Internet

On 15 January 2022, the Hunga Tonga–Hunga Haʻapai volcano exploded 65 km north of Tonga's main island. The country's only international internet cable survived the blast — for 89 minutes. Then something travelled across the sea floor and tore 80 kilometres of it to pieces. Tonga was offline for 38 days. This episode follows what actually happens when a cable breaks: how a message reaches an island in the first place, what an undersea cable is (a hose full of glass), why around 200 of them break every year without anyone noticing, and why this one was different. It follows the money that stopped moving, the satellite backup that existed only on paper, and the ship that sailed 4,700 km to make the repair. And it compares Tonga with two other cuts — the Baltic in 2024, where two severed cables changed almost nothing, and the Red Sea in 2024–2025, where a drifting ship slowed the internet for a quarter of Asia–Europe traffic — to show the difference between having backups and actually being resilient. CHAPTERS 0:00 Saturday evening, Nukuʻalofa 1:02 How the internet reaches an island 2:26 Cables break all the time 3:18 Two cables, two times 3:48 The underwater avalanche 4:40 A backup on paper 5:35 What actually stops: money 6:30 The Baltic: two cables cut, nothing happened 7:17 The Red Sea: the long way round 8:42 Three cuts, three outcomes 8:58 How you fix a cable 2.5 km down 10:53 Day 38 11:29 The right kind of second cable 12:19 Redundancy vs resilience ABOUT THIS CHANNEL SYSTEM DOWN explains the hidden systems civilisation depends on, through the moments they fail. Researched and written by an infrastructure engineer. The narration is an AI voice, and AI was used in production. Some shots are illustrative reconstructions made with AI (the underwater avalanche, the drifting ship and its anchor, the repair deck, a money-transfer screen); the eruption imagery is real NOAA and NASA satellite and astronaut imagery. KEY SOURCES (full list of 35 in the pinned comment) Clare et al. (2023), Science 381 — https://www.science.org/doi/10.1126/s... Seabrook et al. (2023), Nature Communications 14:7881 — https://doi.org/10.1038/s41467-023-43... NIWA (2023), Tonga eruption caused fastest ever underwater flow — https://niwa.co.nz/news/tonga-eruptio... Cloudflare (2022), Tonga's internet outage — https://blog.cloudflare.com/tonga-int... APNIC Blog, U. Speidel (2022) — https://blog.apnic.net/2022/03/01/whe... RNZ (2022), how an internet blackout left many desperate for money — https://www.rnz.co.nz/news/world/4610... ABC News (2022), Tonga's internet cable restored — https://www.abc.net.au/news/2022-02-2... TeleGeography, Submarine Cable FAQs — https://www2.telegeography.com/submar... RIPE Labs (2024), Baltic Sea cable cuts — https://labs.ripe.net/author/emileabe... Kentik (2024), What caused the Red Sea submarine cable cuts? — https://www.kentik.com/blog/what-caus... CREDITS Eruption from orbit: NOAA (GOES West). Astronaut photographs ISS066-E-117965 and ISS066-E-117997: NASA. Atmospheric wave image: NASA/JPL-Caltech/GDGPS. Tongatapu before and after: contains modified Copernicus Sentinel data 2021–2022. Cable sample photographs: Bill Burns / atlantic-cable.com, used with permission. Seafloor rendering built from Mackay, K. (2022), Digital Elevation Models of Hunga Volcano (v1.0), Zenodo, https://doi.org/10.5281/zenodo.7456324 — CC BY 4.0 (https://creativecommons.org/licenses/.... Survey data: NIWA–Nippon Foundation Tonga Eruption Seabed Mapping Project (TESMaP). Rendered by SYSTEM DOWN; colour and relief shading changed. Flow-path figure: Seabrook, S., Mackay, K., Watson, S.J. et al., Nature Communications 14, 7881 (2023), CC BY 4.0 — cropped and adapted for this video. Cable routes are illustrative, drawn by SYSTEM DOWN from Natural Earth data. Latency data: Cloudflare Radar. Stock footage: Envato Elements and Pexels. Music and sound effects: Envato Elements. #submarinecables #internet #tonga