Submarine Cables

Submarine communications cables are laid on the sea floor across the world’s oceans and seas. In the late 1850’s the first transatlantic telegraphic cables were laid. Today most of the cables use fibre optic technology to carry digital data, such as telephone and internet traffic. Modern cables are as thin as 25 millimeters in diameter, and weigh about 1.4 tonnes per kilometer. The majority of these cables lay in deep sea beds. Today ninety nine percent of the world’s oversea data traffic is carried in these cables.

The cables are capable of carrying multiple terabits per second. Whereas, satellites only offer around 1,000 megabits per second, with a higher latency. These systems, with multiple paths to account for cable breaks, typically cost several hundred million dollars to produce. Most of the cables in use today are produced by many governments, data carriers, and companies working together. Today Tata Communications is the only privately owned fiber network across the globe. In the last few decades, there has been a considerable effort to lay cables in the Pacific Ocean in order to strengthen the connection between American and Asian economic markets. Whereas before Asia became highly significant to the world economy, more than seventy percent of submarine cables were laid across the Atlantic. Antartica, to date, has not been reached with a submarine communications cable. It is still highly infeasible due to the massive moving tracts of ice and temperatures reaching -112 degrees Fahrenheit. 

Submarine cables have been broken by fishing trawlers, anchors, earthquakes, undersea currents, whale entanglements, and even shark bites. In the 1980’s the practice of submarine cable burial was adopted. Yet there are still around a hundred significant repairs made around the world per year. 

It is infeasible to protect and surveil all of the world’s submarine cables. The practice of redirecting and/or destroying the cables has been carried out by intelligence gathering services for over one hundred years. Maps for most of the world’s submarine information cables are publicly available, to ensure that shipping and fishing industries can locate and avoid them. Government wiretapping and the damage to cables by criminal organizations is common. For example, in 2010, off the coast of Norway, a nuclear powered submarine, capable of diving more than 10 times deeper than most manned submarines today, surfaced due to an internal fire. Inside, fourteen Russian sailors were killed, many of them were highly decorated military officers. The suspicion is that the submarine was cutting internet cables carrying trillions of dollars worth of the world’s financial transactions. The Russian government insists this was just a research vessel. So many different governments are involved in the construction of these cables, where they start and end, that it is very complicated to determine who is responsible for their maintenance and security. 

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