Subsea cable damage can plunge an entire nation into digital darkness, leading to communication breakdowns, disrupted digital services, and mobility failures.
As the backbone of global internet connectivity and energy security, subsea cable networks are critical components of the digital ecosystem. Each submarine cable contains optical fibers that carry vast amounts of electricity or data to receptors at the other end of the cable.
With the growing reliance on smart technologies across industries, undersea cables now carry 99% of the world’s internet traffic, transmitting copious amounts of digital data. These cables facilitate financial transactions, cloud computing, government communications, and other essential services, ensuring operational efficiency and seamless user experiences (UX).
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Cable operators understand the impact of unexpected outages as the inability to access data can quickly result in considerable economic ramifications as they facilitate trillions of dollars of financial transactions every day. For this reason, operators carry out regular checks to mitigate such risks through physical repairs or by providing alternative routes bolstered by integrated redundancies.
Currently, more than 500 active and planned cable systems span the ocean floors, yet they are vulnerable to various risks, including fishing activities, ship anchors, seismic activity, and ageing infrastructure. The Royal Institute of International Affairs estimates that the global subsea cable network stretches over 1.4 million kilometers, making continuous maintenance a challenge. Each year, approximately 150 to 200 faults occur, with the International Cable Protection Committee (ICPC) identifying fishing and ship anchors as responsible for 65-75% of all failures. Natural phenomena contribute to about 10%, while cable component failures account for around 5%.
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Anatomy of Subsea Cables
Undersea fiber optic cables are designed to last at least 25 years with minimal maintenance, but human activity remains a significant threat. These cables, typically 0.8 to 1.2 inches thick, feature multiple layers of protective material surrounding a glass fiber core.
If the fiberglass core breaks, data transmission is interrupted, requiring rerouting through another cable. In areas reliant on a single cable, such damage can cause complete internet blackouts. Even if only the protective layers are damaged, transmission efficiency declines. In both cases, repair crews must pinpoint the damage location. Using light signals and their reflections, technicians can identify the breakage point, while shunt faults (insulation damage) require electrical signal testing to track faults.
Sharks’ Contribution to Subsea Cables
Studies have shown that sharks have occasionally bitten subsea cables; however, these occurrences have rather been insignificant. Between 1901 and 1957, 28 cases of fish-related cable damage were recorded. From 1959 to 2006, only 11 cases required repairs due to fish bites, accounting for just 0.5% of all faults. The first recorded shark bite of a deep-sea fiber optic (1060-1900 m) cable’s polyethylene sheath occurred between 1985 and 1987 off the Canary Islands. These incidents led to design improvements, effectively eliminating the issue. Interestingly, it is believed that sharks are super-sensitive to electromagnetic fields (EMFs) and may be attracted to the stronger fields produced by power cables instead of fiberoptic cables that only transmit a small amount of electricity to power the repeaters.
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Repairing and Monitoring Subsea Cables
When an underwater cable fails, pinpointing the fault can be achieved through multiple techniques:
- Signal Testing: Technicians send signals through the cable to detect disruptions, using time domain reflectometry (TDR) to measure signal travel time and pinpoint breakage locations.
- Acoustic Monitoring: Remotely operated vehicles (ROVs) equipped with sonar detect cable movement or breaks.
- Visual Inspection: Divers or ROVs confirm damage locations once a general area is identified.
- GPS and Mapping: Geographical data narrows search areas, especially when cables are buried or shifted by currents.
- Cable Surveys: Regular monitoring helps maintain updated condition maps, facilitating efficient fault detection.
Today, maintenance agreements ensure access to ROVs for repairing buried sections. SCARAB (submersible craft assisting recovery and burial) vehicles enable post-repair cable reburial, minimizing future faults and service disruptions.
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The Role of Subsea Cable Personnel
Subsea cable installation and maintenance requires specialized expertise. Training programs equip personnel with the knowledge to navigate marine environments, cable handling, and equipment operation. Safety remains a priority, with training focusing on risk management, emergency procedures, and industry regulations. Hands-on simulations provide practical experience in installations and troubleshooting, while continuous learning ensures professionals stay updated with evolving technologies.
Rerouting and Redundancy Strategies
Strategic cable route planning and network redundancy enhance subsea cable resilience. In regions with multiple cables, data traffic is rerouted swiftly in case of disruption. However, where outages are frequent, satellite communications are gaining traction as backup solutions. Low Earth orbit (LEO) satellites are emerging as viable redundancy options for enterprises, governments, and military operations.
In the Middle East, subsea cable operators like GBI, Telecom Egypt, stc, and Salam collaborate with partners to ensure redundancy, preventing customer outages.
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AI-Enabled Observation Centers and Cybersecurity
Subsea cable observation centers now leverage AI-powered technologies to monitor cable integrity and alert nearby vessels of potential hazards. With increasing data volumes being transmitted, cybersecurity threats such as cable tapping and data theft are rising. To counteract this, cable operators are collaborating with cybersecurity specialists to develop advanced protective measures and enhance network resilience. Since subsea cables are considered an easy target for sabotage activities, geopolitical tensions also play a part in cable connectivity disruption.
To combat this, Fincantieri and Telecom Italia’s Sparkle are developing surveillance and protection solutions for subsea cables, while NATO’s Operation Baltic Sentry is deploying elite divers, submersible drones, and naval vessels to protect underwater infrastructure. Similarly, the Quad Partnership for Cable Connectivity and Resilience is fostering international cooperation to secure strategic submarine cables.
Challenges in Regulatory Frameworks
Maintaining and securing subsea cables is hindered by jurisdictional complexities. Most faults result from accidental human activities, and while many cables are mapped, they often lie in legal gray zones. Under United Nations (UN) law, nations have full jurisdiction within 12 nautical miles of their coastlines, but many subsea cables extend into exclusive economic zones (EEZs) up to 200 nautical miles offshore. This creates uncertainty in international accountability and protection efforts.
The newly established International Advisory Body for Submarine Cable Resilience—formed by the International Telecommunications Union (ITU) and the International Cable Protection Committee (ICPC) in late 2024—aims to enhance global dialogue on cable resilience and protect this vital infrastructure. The advisory body consists of 40 industry and government leaders, including representatives from submarine cable operators, telecommunications firms, maritime authorities, and UN agencies.
Conclusion
The rapid adoption of bandwidth-intensive applications, growing smartphone penetration, and increasing reliance on cloud services are driving demand for high-speed, low-latency connectivity. While earlier investments in subsea cables were focused on cost-efficient, high-bandwidth international connectivity, today’s priorities include high-quality, resilient networks.
As submarine cables serve as the lifelines of the digital age, strengthening their resilience is a shared global priority. Collaborative efforts to implement best practices and enhance security will ensure the continued reliability of this critical infrastructure in an increasingly digital world.
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