Reliance on global high-speed telecommunications is higher than ever before. From urgent financial transactions to endless video live-streaming, undersea cables support numerous aspects of our modern lifestyle that we may not be aware of, making it one of the backbones of the global economy. In fact, commercial undersea cables carry about 97% of the world’s internet and telecommunications data, according to a 2019 report by StableSeas.

 As of 2020, there are over 1.2 million kilometers of submarine cables in service globally, TeleGeography reported. These cables carry over $10 trillion of financial transactions, as well as massive amounts of data and internet traffic across the world at the incredible speed of millions of miles per hour. Various sectors, including the international banking industry, commercial trade, defence data, and daily internet usage, relies on this critical infrastructure. Concerningly, the integrity of this vital global communication is significantly at risk from accidental and deliberate damages.

As 5G and other technologies transform our societies into highly integrated networks, protecting our digital infrastructure – such as undersea fiber-optic cables – becomes more important than ever. Let’s dive deeper to understand the challenges facing submarine fiber-optic cables and how to overcome them.


Accident-Prone Environment

Submarine cables are engineered to sustain around 25-years of shelf life, however they are often retired earlier than that when they start to become economically obsolete. Over that long period of time, the environment takes its toll on the cable. Shifting tides, erosions, storms, and saltwater intrusion are all potential disruptors of data flow. As a matter of fact, around 6% of cables are damaged through abrasion as the current scrapes cables against rocky surfaces. These damages coming from the environment often cause a variety of issues, starting from minor outages and lowered speeds to a complete loss of connectivity.

Anchor Dragging and Fishing Activity

Not surprisingly, the larger and more significant physical threats are man-made, coming from accidents due to fishing vessels and dragged anchors. This type of accidental damage make-up about 60% or two-thirds of all submarine cable faults, TeleGeography reported. This accident occurs when fishing boats and large ships are dragging their anchors outside the designated anchoring areas, thus hitting subsea cables. Recent fault records have indicated that merchant ships sometimes forget to fasten their anchors securely when travelling during short passages.

Threats from Shark Bites

Cable faults due to shark bites are exceedingly rare, and it is perhaps the biggest myth cited in the press. While it is true that in the past, some curious fish and sharks have bitten a few cables and caused damage, they are not a major threat. Both barracuda and sharks have been found to cause cable failure in the past, as reported by the 2009 UN Environmental Program report. Their bites tend to penetrate the cable insulation, thus allowing seawater to compromise the power conductor.

 Damages by Extreme Seismic & Weather Events

Natural disasters – such as mudslides, typhoons, tsunamis, and earthquakes – are also major threats to undersea fiber. In Asia’s underwater network, a large number of cables is concentrated in the middle of a major seismic belt, which resulted in many catastrophes in the past where natural disasters severed about half of the pre-existing trans-pacific cables. Quake-damaged undersea cables are, unfortunately, quite common, especially in earthquake-prone zones around Japan and Taiwan. When submarine cables are severed following a major earthquake or other natural disaster, it can cause disruptions in internet access and communications traffic that could cost both money and time.

The Solution

To overcome damages to undersea cables, the subsea networks developed over the past 5 years were designed with enhanced physical security in mind. In order to protect the fiber-optic cable from water environmental hazards, the undersea cables are typically wrapped in multiple layers of protective coating. To further increase its protective property, the cable is encased in a protective pipe that extends for several miles from the shoreline. In some cases, operators may use automated technologies that are placed inside the cable housing’s repeaters. This technique can help to avoid the cost and time of pulling the damaged cable out of the sea to fix it, only to redeploy it underwater

To deal with extreme seismic and weather events, the Southeast Asia-Japan Cable (SJC) consortium designed an underwater fiber cable deployment path that intentionally avoids the earthquake-prone zone in North Asia. Similarly, the route of NTT Communications Corporation’s (Tokyo) Asian Submarine-cable Express (ASE) has taken a similar approach. Their new line is designed to go around the damage zone, rather than taking the shortest, straightest line from both ends. This model is intended to bypass high-risk zones and avoid the damage caused by both earthquakes and typhoons.

Final Thoughts

Ultimately, undersea cables help keep the global economy well-functioning and the people connected. Protecting these critical infrastructures from any compromise is a vital national interest of a country, and one way of doing so is by performing regular repairs and maintenance. Doing so will ensure the cables’ integrity is not being threatened by any disruptive damages. Risk-mitigation steps can be done by using a monitoring system to supervise the fiber-optic network in real-time and sound alerts when problems arise.

Considering the importance of protecting and monitoring undersea fiber optic cables, it is essential for telecommunication companies to continue their effort in overcoming the challenges of submarine cables maintenance. The range of VIAVI Testing and Monitoring Tools are designed specifically to handle all aspects of the submarine cable network, from the building stage right through to activation and monitoring. Protect and monitor the submarine network with end-to-end solutions from VIAVI.



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Channel Marketing Manager - APAC

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