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Tonga "disconnected" How fragile is the global submarine cable?

According to foreign media reports, affected by the eruption of the submarine volcano, the submarine cable of Tonga in the South Pacific island country has been confirmed to be cut off, the national telephone and network lines were interrupted, and about 105,000 residents on the island could not get in touch with the outside world. Dean Viveka, network director of New Zealand's Southern Cross Cable Network, said repairing the cable "could take two weeks".


Today, submarine cables are the cornerstone of globalization and global communications. Millions of kilometers of submarine cables encircle the globe, providing internet and communication connections between continents. For countries around the world, especially coastal countries or island countries such as Australia, Tonga, and Fiji, submarine cables are important infrastructures that are vital to the daily operation of society.

Disruption or disruption of this critical infrastructure could have catastrophic local, regional, and even global consequences. This is exactly what happened in Tonga after disasters such as volcanoes and tsunamis. But this isn't the first time a natural disaster has cut vital submarine cables, and it won't be the last. Australia's "Conversation" magazine published an article that Tonga's volcanic eruption actually revealed the vulnerability of the global telecommunications system.

What happened to the Tonga submarine cable?

Tonga has only been connected to the global undersea telecommunications network in the past decade. The island nation relies heavily on the undersea cable communication system because it is more stable than other technologies such as satellite and fixed infrastructure.

The current situation in Tonga remains fluid, with certain details yet to be confirmed. Currently, the Tonga island is covered in volcanic ash, and the submarine network cables and telephone signals are disrupted, as is the Internet signal, which has severely affected its online services.

The Conversation magazine article stated that Tonga is particularly vulnerable to such disturbances. Because there is only one cable connection between Tonga's capital Nuku'alofa and Fiji, this submarine cable is 872 kilometers long, and it is the key to connecting Tonga to other countries and regions in the world.

According to the latest news from the Australian Broadcasting Corporation on the 18th, Tonga cable director Samiela Funua said that the cable was cut in two places, but maintenance personnel would not be allowed to access the cable until the volcanic activity ceased.


Dr. Amanda Watson, a research fellow at the Australian National University's Department of Pacific Affairs, said the cable connecting Tonga and Fiji had been damaged before. In 2019, the cable broke in at least two places, and repairs took about two weeks.

Dr. Watson said: "Tonga is not the only Pacific island that relies on a single cable to connect to the outside world, and hopefully in the future, we will see more cable arrangements in place to avoid a complete outage like the current one."

Undersea cable risks are not unique

There are currently about 428 submarine cables worldwide, with a total length of 683,508 miles (about 1.1 million kilometers), providing Internet and communication connections to countries and regions around the world.

Such networks can overload, especially if they are hit by natural disasters.

The cable is laid within the shortest distance between two points on the earth's surface, so because of the low cost. They also had to be laid along with specific geographical locations that facilitate placement, which is why many cables gather in some of the "throat arteries", such as the Hawaiian Islands, the Suez Canal, Guam, and the Shun Strait in Indonesia. But the trouble is that these areas are also often where major natural disasters occur.

Once damaged, people can take several days to weeks, or even more, to repair the cable, depending on the depth and accessibility of the cable. In times of crisis, such power outages make it harder for governments, emergency services and charities to participate in the recovery efforts.

Many of these submarine cables are located close to or pass directly through active volcanoes that are areas affected by tropical cyclones and/or active seismic zones.

Not only Tonga, but also Australia, New Zealand and other countries and regions are very fragile submarine cables. Australia, for example, only connects to global communications networks from Sydney and Perth through only a few connection points. Large underwater landslides have previously occurred off the Sydney coast. In the future, similar events are also likely to disrupt the key "big arteries" of local networks.

Dr. Anthony Berkin, a senior research fellow at the Australian Institute for Strategic Policy, said more work is needed to ensure that the cables are more flexible in the future.

How to manage future risks?


The Dialogue article said the Tonga incident once again highlights how fragile the global undersea cable network is and how fast we can "drop off."

Given the vulnerability of submarine cable communication networks, the first step in risk reduction is to conduct research to quantify and assess the actual risks of submarine cables to specific locations and different types of natural disasters.For example, tropical cyclones (hurricanes/typhoons) occur frequently, but other disasters, such as earthquakes and volcanic eruptions, occur less frequently.

The second is to achieve global data sharing. There is currently little public data on the risks posed to global submarine cable networks. Once they know which cables are vulnerable, and which types of danger are vulnerable, countries can develop plans to reduce the risk.

At the same time, governments and telecommunications companies should try to ensure the diversification of communication methods, such as by using more satellite-based systems and other technologies, thereby reducing their reliance on submarine cable communication systems.