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Subsea cables fight back against the menace of earthquakes

Ciaran Delaney Exa.jpg

A transatlantic cable owned by Exa Infrastructure has played a major role in monitoring the ocean bed, including gathering earthquake data.

The UK’s National Physical Laboratory (NPL) installed 12 sensors on the cable between the UK and Canada and found they could identify the location of earthquakes.

Exa’s COO, Ciaran Delaney (pictured), said: “Earth is being observed as never before; we are excited by the potential of NPL’s breakthrough sensing capabilities using our subsea cables and by the possibility of enabling such scientific advancements.”

According to Exa, the project used the “classic” Exa North and South cables, which went into service in 2001. It was previously known as GTT Atlantic, though it has had some other names over its 21-year history. The cable was built for 360networks by Tyco Submarine Systems.

NPL, which has been working with Google and a number of academic institutions on the survey, plans to increase the number of sensors to 129.

“Crucially, the data from these sensors can be recorded, continuously and in real time,” says the research institution in west London, which in 1945 employed Alan Turing – fresh out of wartime code-breaking at Bletchley Park – to work on one of the world’s first-ever computers, ACE.

At Google, which announced at earthquake detection trial last year, principal engineer Valey Kamalov said: “Synergy of optics, geophysics, and submarine cable engineering produced extraordinary results applicable to climate change and public safety. It is an excellent example of public-private partnership with clear societal benefits. I encourage the cable industry to watch the technology’s progress.”

NPL’s principal research scientist Giuseppe Marra hoped that other subsea cable companies will offer their facilities. “We can now harness existing underwater cables as a valuable tool for Earth sciences and beyond.”

This is not the first use of subsea cables for earthquake monitoring, though it’s probably the biggest so far. In April, two Italian research institutes said they had used TIM’s 15km cable linking Milazzo in northern Sicily to Vulcano, an island off its north coast, to investigate earthquake detection.

And in another geologically unstable area, off the coast of Alaska, Alaska Communication said last year it will work with the University of Michigan to collect data from the ocean floor using the company’s subsea cable.

But earthquakes have long been a challenge to subsea cables too. In April 2011 one of the most powerful earthquakes in modern history triggered powerful tsunamis that caused widespread devastation across east Japan, and in the process damaged portions of several undersea cable systems landing in the affected regions.

Now scientists at NPL wondering what else can be detected via the subsea cable industry’s infrastructure – the slowing down of the Gulf Stream due to rising global temperatures, perhaps.

The research team now plans to test earthquake detection on multiple submarine cables, including those in seismically active areas such as the Pacific Ocean where, they say, “there are more opportunities to properly assess the ability to accurately detect tsunamis”.