Two Subsea Cables Off Perth Report Shunt Faults After Suspicious Vessel Activity

Subco, the company that owns multiple subsea fibre links serving Australia, reported that two of its cables experienced shunt faults in close succession off the coast of Perth. The affected systems were Indigo-West (connecting Perth with Indonesia and Singapore) and Indigo-Central (with endpoints in Victoria, Tasmania and New South Wales). Subco founder and CEO Bevan Slattery said the faults were detected at roughly the same time and in close proximity to one another.

What Happened

According to Slattery, the errors occurred shortly after a vessel passed through the area and he published track data showing the craft was approximately within the location where the faults occurred. Subco described the timing and proximity of the two faults as notable because they happened inside the federally declared Submarine Cable Protection Zone off Perth.

"Earlier tonight: Shunt faults on two systems (Indigo West and Indigo Central) straight after each other and in close proximity to each other. Remarkably this also happened in the Submarine Cable Protection Zone off Perth Australia. Coincidently some suspicious/coincidental activity from a vessel near the location and timing of the shunts occurring," Slattery wrote on LinkedIn.

Investigation Underway

The Australian Federal Police (AFP) told Tom's Hardware that it has received a report of a crime and is assessing the information. The AFP said further comment will be provided "at an appropriate time," indicating investigators are treating the matter seriously while they gather evidence.

Technical Details

A shunt fault occurs when a conductor's insulation is breached and it unintentionally contacts another conductor or the seabed, creating a short circuit. Such faults can be caused by physical damage to the cable's protective layers, either accidentally (for example, from anchors or fishing gear) or deliberately.

Protection Zone And Context

Australia established its Cable Protection Zone in 2007. The zone near Perth extends roughly 51 nautical miles from shore and covers seabed depths greater than about 6,500 feet (2,000 metres). Because submarine cables carry the bulk of international data traffic, damage to them can have significant economic and national-security implications.

Global Pattern And National Concern

There is growing international concern about interference with undersea infrastructure. The article noted precedent in other regions: Finland has experienced undersea cable disruptions that led to prosecutions of suspected vessel crew, and Taiwan has increased patrols after sightings of foreign research vessels lingering above cable routes. The timing of the Perth faults coincided with a new report from the National Security College at the Australian National University highlighting rising risks to submarine cables.

Summary: Two Subco-owned subsea cables suffered shunt faults off Perth at nearly the same time and place. A vessel was tracked near the site when the faults occurred, and the AFP has received a crime report and is assessing the matter. Investigators and security officials are monitoring the situation while the cause—accidental damage or deliberate interference—remains unconfirmed.