Submarine cables are the spine of worldwide connectivity, so when a cable breaks, it may be an enormous deal. Or not (due to redundancy).
This put up covers every part you should find out about subsea cable breaks: what causes them, the best way to stop them, and what’s going to be required to take care of the world’s submarine cables sooner or later.
How uncommon are cable breaks?
Submarine cables break on a regular basis. On common, two to 4 break someplace on this planet each week. Whereas injury is extra frequent in some areas than others, these breaks—or “faults”—finally occur to nearly each cable.
If cables exit of service so typically, why don’t I hear about it?
More often than not, cable faults solely make the information if a number of programs go offline or injury happens in geopolitical hotspots. Simultaneous breaks usually tend to have an effect on service high quality, and a few islands could lose their undersea connectivity altogether (like within the Shetland and Matsu Islands).
You not often hear about different cable faults as a result of most telecom suppliers comply with a “security in numbers” strategy. By spreading their networks’ capability over a number of cables, operators be sure that if one breaks, their community will run easily over the others till the injury is repaired. That is known as community redundancy.
To reduce downtime, cable house owners additionally maintain standing agreements with upkeep suppliers that hold ships on standby, ready to deploy spares of additional cable size and make wanted repairs shortly.
What causes cables to interrupt?
Most faults are attributable to “exterior aggression.” That sounds scary! However this time period solely signifies that a cable did not endure a technical fault by itself, and was as an alternative broken by exterior forces. Most come from fishing gear, regular anchoring exercise, and pure disasters like undersea earthquakes. Inner element or gear failure causes one other, smaller class of faults.
(In case you’re questioning, no cable faults have been attributed to shark bites since 2007.)
Are cables ever broken on function?
State-sponsored sabotage is extraordinarily uncommon, and most publicly recognized examples are a long time outdated (for instance, in World Struggle I or the Spanish-American Struggle).
Nonetheless, routine cable faults can resemble sabotage if operators or governments aren’t sure of what prompted them. In any case, deniability is a key ingredient of recent “grey zone” assault vectors.
Whereas much less thrilling, some fishermen could minimize a cable on function. This will occur if their gear snags on a cable and they’re able to carry it to the floor. To discourage this, cable operators typically provide to pay for misplaced gear if fishermen sacrifice their gear as an alternative of tampering with the cable.
How do we all know what occurred to a cable?
In circumstances like Tonga’s, the place a volcanic explosion famously disrupted the island nation’s solely subsea connectivity, it’s straightforward to conclude that environmental injury prompted a break.
In different situations, figuring out the reason for a break takes time. Upkeep crews typically set sail figuring out the place injury occurred—however not what prompted it. As soon as on-site, preliminary hypotheses could be confirmed or denied based mostly on how the cable appears to be like.
One device cable operators can use to find out the doable trigger of harm from afar is Computerized Identification System (AIS) information.
Ships use AIS to transmit their location again to shore or to different close by vessels. This helps guarantee secure navigation and is required for some ships beneath worldwide legislation. If a ship crosses a cable on the similar place and time that it breaks, that ship could have prompted the injury (unintentionally or in any other case).
So if AIS exhibits a international ship crossing a cable, that’s proof of sabotage?
Official dedication of a fault’s trigger is finest left to operators, upkeep crews, and authorities investigators.
When AIS exhibits a vessel passing forwards and backwards over a cable proper earlier than it breaks, it may look suspicious. Typically, that is simply mundane fishing exercise—e.g., a trawler making a number of passes over the seabed to scoop up fish. It could even be authorized, as not all international locations have protected zones round cables.
AIS information also can point out the place a vessel is flagged. Nonetheless, it’s not unusual for fishermen to seek out their catch properly past their residence nation’s shores. China, for instance, has the world’s largest fishing fleet, with vessels routinely touring throughout the globe.
AIS information isn’t all the time out there, although. Typically, AIS is turned off on function with the intention to illegally fish in sure areas. Different occasions, transmitted information may not be picked up by receivers. (AIS is restricted in vary as a result of it‘s transmitted wirelessly.)
Decreasing submarine cable faults
There are steps governments and cable builders can take to assist cut back faults, together with liaising with fishermen, burying cables close to shorelines, and selling cable range, based on the ICPC’s record of finest practices.
Repairing the world’s subsea cables
Because the spine of the digital economic system, submarine cables carry practically all intercontinental information and require important funding to take care of. However the trade has struggled to totally perceive and handle the challenges going through the upkeep sector.
That is why we wrote The Way forward for Submarine Cable Upkeep: Traits, Challenges, and Methods.
This landmark report, by Mike Constable of Infra-Analytics and TeleGeography’s Alan Mauldin and Lane Burdette, gives context and insights for trade professionals, authorities policymakers, and different stakeholders to grasp additional the importance of this crucial sector and its function in guaranteeing the safety and resilience of submarine digital infrastructure.
You possibly can obtain the complete report right here.
Keep on prime of cable information and evaluation
This research was finalized in 2025. However you’ll be able to entry probably the most up-to-date forecasted information for kilometers of recent and retiring submarine cables with a subscription to our Transport Networks Analysis Service. These forecasts prolong for 10 years and are up to date yearly.
Transport Networks analysis service additionally options our database of cable faults, which we recurrently replace.
