Submarine Cables Could be Repurposed as Earthquake Detectors

In a paper published in Science, Giuseppe Marra, of Britain's National Physical Laboratory (NPL), proposes to shine a little light into the oceans by co-opting infrastructure built for an entirely different purpose. From a report: Dr Marra and his colleagues hope to use the planet's 1m-kilometre network of undersea fibre-optic cables, which carry the internet from continent to continent (see map), as a giant submarine sensor. Dr Marra is particularly interested in earthquakes. The dry bits of the planet are well-stocked with seismographs. The oceans are much less well covered, with only a handful of permanent sensors on the sea floor. This means that many small earthquakes go unrecorded because the vibrations they cause are too mild to be picked up by distant land-based sensors. The genesis of the idea is a good example of the way in which advances in one field of science can lead to new developments in other, apparently unrelated fields.

They could also be used to detect temp changes

[Anonymous Coward]

This is an implementation of Rayleigh Scattering technology, which has been around awhile and used for FO sensing of movement and/or temp changes. It has limitations, such as difficulty in determining exactly where the earthquake took place along the line, unless you do a lot of calibration which would require actually disturbing the lines to verify.

Re:

[mikael]

It used to be possible to detect where a fault in an copper or fibre-optic cable through the use of time-domain reflectometry. Any defect would reflect some signal back, and the intensity/time could be correlated.

"1m-kilometre"

[Rick Schumann]

Wow, that's asking quite a bit of 39 inches of fiber optic cable.

So in other words use an OTDR as a seismograph

[pecosdave]

I don't see why it wouldn't work. I guess they just didn't want to bust out the Optical Time Domain Reflectrometer nomenclature.

Re:

[Obfuscant]

Nobody doesn't understand why this wouldn't work, which is why the idea is several years old and is being actively used for land-based seismic sensors already, and if not being used has been floated as a use for dark fiber for long distances. There is no significant difference between undersea and on-land use of fiber in this context.

My first response to this article is that Science has become subject to the same error of "dups" that /. has.

Re:

[Anonymous Coward]

Nobody doesn't understand why this wouldn't work

Jesus fuck man, I don't understand what you didn't not say .. because you didn't not don't say it well enough to allow me to doesn't not have any fucking idea what you did say.

Sure as fuck lived up to your nickname there.

Re:

[pecosdave]

Using fiber as a high-tech weather rock. [wikipedia.org] I like it.

Re:

[pecosdave]

I've done lots of LAN/SAN fiber, and even some SDI over single-mode, but I've never done telecom fiber. I've always wanted to dig into what's going on with the long-range backbone stuff.

They can also be used ...

[CaptainDork]

... as stationary hydrophones to listen for ships above and beneath the surface.

Each vessel produces its own signature of vibrations caused by reefers, engines, screws, power source hum ...