Cable failures: the real risks behind the conspiracy theories

Matt Walker/Ovum
11 Feb 2008

Four separate reported and confirmed failures of undersea cables serving the Middle East and North Africa over the last week have inspired conspiracy theories as to what caused this rare coincidence.

Undersea cable networks are an under-appreciated but essential part of modern life. They now carry well over 95% of the world's international telecommunications traffic.

As trade rises as a share of global GDP - it's now over 30% - reliable connectivity becomes a key ingredient to growth. Some drivers of economic growth - outsourcing, offshoring - would be nearly impossible without it. As such, the undersea cable networks that support this connectivity are clearly vital to global commerce.

At the same time, cables are nearly impossible to secure. Cable landing stations are often located in remote areas and usually staffed with a handful of technical employees, not teams of armed guards.

Moreover, a typical transpacific system stretches around 20,000 km. Even if the private cable owners increase security for the "dry plant" segment of such networks, securing the wet plant is problematic. Cable owners work hard to minimize accidental damage, making cable routes available to those that need to know, such as fishermen, navies, and research vessels.

Cable routes also deliberately avoid, as much as possible, such hazards as earthquake-prone zones and rocky seabed. However, there is an unspoken assumption that the networks are safe from deliberate human sabotage. The recent spate of cable failures in a politically volatile region has called this assumption into question.

Data from the field

In deep waters, cable cuts are rare. According to one paper presented at last year's SubOptic conference in Baltimore, Maryland, rates of cable fault in water more than 1km deep are less than 0.1 faults per year per 1,000km of installed cable. This implies around 50 deepwater repairs per year, globally.

At depths of less than 1km, failure rates hovered between 1-2 per 1,000km in the 1990s, but have been steadily declining. According to a SubOptic 2004 paper, the rate in 2003 was 0.2 fault per 1,000km. This same paper estimated that 60% of all cable cuts occur in waters less than 100 meters deep. Of all cable faults, roughly three-fourths are due to "external aggression", the bulk of which is accidental human activity, namely, fishing, anchors, and dredging; a small portion of the 75% is natural, e.g., from earth movement and chafe, sometimes caused by earthquakes.

Equipment failures and unknown - some portion of which could be theft or attempted theft or sabotage - account for the remainder. In deep water, natural causes and/or cable equipment failure dominate; human causes are rare. Hence, when cables fail in deep water, usually a natural and detectable event is the cause, as with the late 2006 earthquake near Taiwan, the last quake to cause multiple simultaneous outages. An earthquake, albeit small (magnitude 4.8) was reported February 2 in the Persian Gulf and could have affected cables there.


Related content

No Comments Yet! Be the first to share what you think!