Two subsea cables off Perth suffer ‘concerning’ damage. Lasers could help protect them

Two subsea cables off Perth suffered concerning damage earlier this week, prompting urgent calls for investigation. Bevan Slattery, CEO of subsea cable company SubCo, confirmed that the faults occurred over the weekend and described the situation as a “concerning development.” The cables, vital for Australia's digital connectivity, are referred to as the “digital lifeblood of our nation” by Slattery, who urged federal police to act swiftly to determine the cause of the incident. The damaged cables are located within the Perth Submarine Cable Protection Zone, a designated area meant to ensure the safety of critical infrastructure. This zone spans over 100 kilometers offshore, where the cables lie on the seabed. Despite these protective measures, the cables remain vulnerable to both accidental and intentional harm. Monitoring such vast underwater regions is challenging, as traditional methods lack the precision needed to detect subtle threats in real time. Australia relies on fewer than two dozen undersea fibre optic cables to maintain its connection to the global internet. These cables, each composed of multiple strands of ultra-thin optical fibre, are capable of transmitting more than 20 terabits per second. This capacity means that even a single pair of fibres could handle the entire data load of the National Broadband Network. Among the affected cables are the Indigo West and Indigo Central lines, which link Perth to Sydney, Jakarta, and Singapore. Together, these cables form a crucial part of Australia’s network of international connections. Currently, only 22 undersea cables are either operational or under construction, highlighting the fragility of the country’s digital lifeline. While satellites play a role in connecting remote areas, they cannot replace the massive data transfer capabilities of undersea cables. As such, the integrity of these cables is essential for maintaining Australia’s place in the global digital economy. The cause of the damage remains unclear, though Slattery identified the issue as a “shunt fault,” a type of electrical failure that disrupts the operation of the cables. Shunt faults can result from various factors, including accidental contact with fishing gear or anchor chains, as well as deliberate interference. Although deliberate acts are a growing concern, most incidents are attributed to unintentional damage. Slattery emphasized that the exact cause will only become apparent once the cables are retrieved during repairs. To better protect these vital links, experts suggest adopting advanced monitoring technologies. One promising solution is distributed acoustic sensing, a laser-based system that detects vibrations along fibre optic cables. This technique works by measuring light echoes generated by minute environmental changes, allowing operators to identify potential threats such as vessel activity or seismic disturbances. The technology can also map surrounding geological structures and offer early warnings for natural disasters like earthquakes and tsunamis. Slattery pointed out that if distributed acoustic sensing had been deployed on the affected cables, the responsible vessel could have been identified almost immediately. The technology is already in use on nearby cables in the same region, indicating that it is a viable option for enhancing security and response times. By integrating such systems, Australia could significantly improve its ability to safeguard its digital infrastructure against both accidental and intentional disruptions.