How Are Internet Wires Laid Down in the Ocean?
99% of global digital communication relies on subsea cables. These cables lie on the ocean floor, transferring data between continents.
Surprisingly thin, about the width of a garden hose, they withstand extreme underwater conditions.
These cables are extremely important for our internet infrastructure, yet many don’t realize the role of deep-sea repair teams who maintain them.
Let’s learn the whole process behind it.
Laying Subsea Cables
Big ships sail across oceans, dropping cables in a continuous S-curve, allowing flexibility for repairs. At depths of up to 4000 meters, the cables are strong enough to withstand the ocean’s pressure and natural wear.
They are rolled out slowly, sinking to the ocean floor, where they become an integral part of the seabed, often covered by coral or marine life.
Cable Vulnerability
Despite their strength, subsea cables can get damaged. Anchors and fishing nets are the most common causes of cable faults, responsible for up to 80% of damages.
Natural hazards, such as underwater landslides, volcanic eruptions, and earthquakes, also play a role, though there are only a few instances. Sharks once attacked cables, but modern cables have protective Kevlar layers, so now it is just another urban legend.
The Importance of Redundancy
Subsea cable networks are designed with redundancy to prevent total internet outages. If one cable is damaged, backup cables on the same path take over, to avoid disruption as much as possible.
This redundancy ensures that even when a fault occurs, most users remain unaffected, highlighting the resilience of the global digital infrastructure that runs through the oceans.
The 1929 Newfoundland Earthquake
In 1929, a 7.2 magnitude earthquake triggered a massive underwater landslide off the coast of Newfoundland. This event severed 12 transatlantic cables in 28 places, marking one of the most significant disruptions in cable history.
Scientists later discovered that the cables helped trace the landslide’s movement, giving new insights into the existence of turbidity currents.
Turbidity Currents and Cables
Turbidity currents, dense underwater flows of sediment caused by geological activity, are a significant threat to subsea cables.
These currents travel at high speeds, smashing through cables across vast distances. The 1929 event helped scientists better understand how these currents can affect deep-sea infrastructure and highlighted the need for stronger cables and faster repair systems.
Repairing Deep-Sea Cables
When a cable is damaged in deep waters, repair ships are dispatched. These ships deploy grappling hooks to retrieve the cable, which is then cut, repaired, and spliced.
The repaired cable is tested to ensure proper functionality before being lowered back to the seabed. In shallow waters, cables are buried in trenches to protect them from further damage.
Deep-Sea Cable Maintenance
Regular maintenance is essential to keep the subsea network operational. Ships and remotely operated vehicles (ROVs) monitor cables for faults.
In deeper waters, robotic plows dig trenches to bury the cables, to give them additional protection from external threats. Advanced technologies, like acoustic sensors, are also used to detect problems and minimize damage.
Emergency Repair Ships
A fleet of standby repair ships is positioned around the world, ready to respond to cable faults. These vessels carry specialized equipment to lift, cut, and repair cables.
On average, it takes 10 to 12 days for a repair ship to reach a damaged cable, but repairs are usually completed in one to two weeks, depending on the location and weather conditions.
Science from Cable Breaks
Broken subsea cables have led to unexpected scientific discoveries. In the 19th century, the laying of the first transatlantic cables revealed the existence of the Mid-Atlantic Ridge.
Later, damaged cables helped scientists discover turbidity currents. Today, cables serve as acoustic sensors, helping monitor underwater environments, track marine life, and even detect earthquakes.
Environmental Challenges
Climate change is also creating new challenges for subsea cable networks. Increased flooding and sediment flow in rivers, like the Congo River, threaten cables with canyon-flushing events.
In other regions, like the South Pacific, volcanic eruptions and tropical storms also pose a constant risk to cables, forcing engineers to adapt cable routes and reinforce protective measures.
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The Tonga Cable Break
In 2021-2022, a volcanic eruption in Tonga destroyed a vital subsea internet cable, cutting off the Pacific Island nation from the rest of the world.
It took five weeks to fully restore the internet connection, although temporary services were restored after a week. This became a serious issue for the island nations who are dependent on subsea cables for communication.
Geographic Diversity of Cables
To improve the strength of the global subsea cable network, engineers are focusing on geographic diversity in cable routes.
By spreading cables across different regions and avoiding known hazards, like volcanic areas or storm-prone zones, the likelihood of multiple cables being damaged simultaneously can be decreased. This could help maintain consistent internet access even in extreme conditions.
Advances in Cable Technology
New technologies are making subsea cables stronger and easier to fix. For deeper waters, cables are now made with lightweight materials, which makes it easier to pull them up for repairs.
Manufacturers are also creating universal joints that work with different types of cables. This helps repair teams from different countries work faster and reduces the time it takes to get the cables back to work.
Reducing Human Damage to Cables
Human activities remain the biggest threat to subsea cables, particularly fishing and shipping. To avoid these damages, some companies have now developed Automated Identification Systems (AIS) that help ships avoid cable areas.
These companies are also educating fishing communities and sailors about the importance of avoiding these cables to prevent damage to global connectivity.
The Unsung Heroes of the Internet
Subsea cables are the backbone of global communication, yet they often go unnoticed. The teams who lay, repair, and maintain these cables are the unsung heroes who ensure the smooth running of our internet.
As technology advances and environmental challenges grow, the importance of these deep-sea emergency services will only increase, as they keep our world connected across oceans.