Scientists Turn Undersea Fiber Optic Cables Into Seismographs

Monitoring seismic activity all over the world is an important task, but one that requires equipment to be at the site it's measuring -- difficult in the middle of the ocean. But new research from Berkeley could turn existing undersea fiber optic cables into a network of seismographs, creating an unprecedented global view of the Earth's tectonic movements. A reader shares a report: Seismologists get almost all their data from instruments on land, which means most of our knowledge about seismic activity is limited to a third of the planet's surface. We don't even know where all the faults are since there's been no exhaustive study or long-term monitoring of the ocean floor. "There is a huge need for seafloor seismology," explained lead study author Nathaniel Lindsey in a Berkeley news release. "Any instrumentation you get out into the ocean, even if it is only for the first 50 kilometers from shore, will be very useful." Of course, the reason we haven't done so is because it's very hard to place, maintain, and access the precision instruments required for long-term seismic work underwater. But what if there were instruments already out there just waiting for us to take advantage of them? That's the idea Lindsey and his colleagues are pursuing with regard to undersea fiber optic cables. These cables carry data over long distances, sometimes as part of the internet's backbones, and sometimes as part of private networks. But one thing they all have in common is that they use light to do so -- light that gets scattered and distorted if the cable shifts or changes orientation. By carefully monitoring this "backscatter" phenomenon it can be seen exactly where the cable bends and to what extent -- sometimes to within a few nanometers. That means that researchers can observe a cable to find out the source of seismic activity with an extraordinary level of precision.

This idea has been around for a while

[WoodstockJeff]

Looks like it's time to get funding for it?

Let me say it first

[nospam007]

It's earth-shaking news!

I know!

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[DethLok]

I so wish I currently had mod points :)

Birds of a feather.

[Ostracus]

"By carefully monitoring this "backscatter" phenomenon it can be seen exactly where the cable bends and to what extent -- sometimes to within a few nanometers. That means that researchers can observe a cable to find out the source of seismic activity with an extraordinary level of precision."

Seems to me the companies that placed the cables could use the same information in maintaining their infrastructure..

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[K. S. Kyosuke]

Or for checking for tampering by foreign subs?

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[nospam007]

"Or for checking for tampering by foreign subs?"

Who do you think is funding this?

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[APL bigot]

Indeed, seems like TDR (time domain refelectometry) to me. Closed circuit radar that shows the location of discontinuities.

Military uses

[godel_56]

I wonder if this could also be used for incidental deep sea surveillance of passing ships and submarines? Maybe it already is but their not telling us.

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[godel_56]

s/their/they're/

Yeah, I know. Failure to proof read. :-(

If you can sense earthquakes from fiberoptic cable

[HotNeedleOfInquiry]

Imagine what you could do with the US Navy's hydrophone network.

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[Anonymous Coward]

SOSUS, an acronym for sound surveillance system, is a chain of underwater listening posts located around the world in places such as the Atlantic Ocean near Greenland, Iceland and the United Kingdom—the GIUK gap—and at various locations in the Pacific Ocean. The United States Navy's initial intent for the system was for tracking Soviet submarines, which had to pass through the gap to attack targets further west. It was later supplemented by mobile assets such as the Surveillance Towed Array Sens