Acoustic sensing is an emerging technology that may become more common in the near future. This technology is testing ways to reduce the number of subsea internet cables that get damaged both accidentally and intentionally.
Today, most of the world’s internet travels via sea. Globally, the physical hardware is made up of more than 5 billion kilometers of fiber-optic cable.
Currently, there are about 574 active submarine cables that span over 1 million kilometers in length.
Ever so often, the grim news that one or more of these important cables has been severed breaks, followed by a period of internet outages and service disruptions.
These cables carry huge volumes of internet data between countries, and reports of damaged telecommunications cables raise alarms in affected regions.
Read: PEACE Submarine Cable Cut in the Red Sea Causes Major Internet Issues in East Africa
Hence, to safeguard against threats such as hidden underwater drones and anchor damage from marine vessels, some companies are deploying fiber optic monitoring systems to observe cable surroundings.
How Acoustic Sensing Works
The technology takes advantage of the acoustic energy that travels through the fiber. A disruption in the flow of this acoustic energy triggers a signal, indicating the presence of an object near the undersea telecommunication cable.
This sensing technology also relies on temperature changes, vibrations, or physical disturbance to the cable itself. Detecting a temperature shift in a buried cable can reveal that a part of it is no longer buried, a situation that could lead to damage.
Acoustic sensing allows companies to track the movement of ships, drones, and divers near undersea cables and to determine their distance from the cable.
Disturbances in the fiber optic signal can record if it’s human footsteps and capture every single footstep around the area.
Identifying Ships
By utilizing this technology, it’s possible to estimate a vessel’s size, pinpoint its location, and, under certain conditions, track its direction of travel as it passes above a subsea cable. This information can be validated using satellite imagery or automatic identification system (AIS) data.
AIS data offers up-to-the-minute details on vessel location, speed, direction, and additional information, facilitating vessel tracking, collision prevention, and enhanced maritime traffic control.
Preventive Solution to Cable Damage
Currently, there is a need to install signal listening devices, or interrogators, every 100 km along a cable. While the sensors can detect vibrations at distances of hundreds of meters, they typically cannot reach several kilometers.
This new technology is preventive, able to issue alerts to those monitoring when a vessel or divers are coming close to submarine cables. An early warning may prevent ships from dragging anchors in areas with cables, reducing cuts.
In the event a vessel or driver is hostile and the intention is to damage cables, prevention will depend on how quickly security patrols receive alerts and respond.
Given the reality that a vessel intentionally dragging its heavy anchor across even a double-armored cable will almost certainly cause damage, quick proactive prevention is crucial.
