Fiber-Optic Cables Are Natural Earthquake Detectors | Hacker News Reader

Fiber-Optic Cables Are Natural Earthquake Detectors

spectrum.ieee.org

44 pointsjonbaer15 comments

In 2010 I built a system to measure DNS latency by piggybacking on user traffic with some sleazy wildcard DNS tricks. After the 2011 Japan earthquake, the data showed the effects of the cable damage and rerouting quite clearly.

https://carlos.bueno.org/2011/07/doppler.html

Great post!

Is there a public version of this chart? “ And that's what we're building right now: an alternate map of the world based not on geographic distance, but on pure network latency.”

Probably not. I tried to get my counterparts at Yahoo/MSFT/AWS to publish a joint map but it didn't go anywhere.

You get how they mean it, but to use the term "natural" here is a bit funny?

Haven't you heard fibre optic cables grow in the wild Amazonian rain forests? Farmers harvest them every month and ship them across the world to ISPs needing them.

Growing up in Brazil, I always played with my monkey climbing optic cables trees. Fun times!

About as natural as the spaghetti tree.

That's ridiculous. The cables are harvested by independent contractors who wholesale them on auction at regional fairs. They are then binned into lots by middlemen who on sell to exporters, who on-sell to importers who distribute the cables to distributors. The distributors then supply retail B2B to cabling companies who in turn are subcontracted by the ISP's you mentioned.

That is why natural fibre optic cables are so expensive these days.

Amazonian, I thought we were getting them from that planet where we also mine unobtanium?

"Incidental" might be the better term

DAS systems typically produce ~10tb of data per 50m of cable per day. So a 1km cable would produce around 73 petabytes per year. The San Andreas fault is around 1300km long, so simply having a cable next to it would produce around 94 exabytes of data per year. It quickly becomes obvious that the computing needs will soak up any cost saving measures. I think it's strange they even mention the cost of a seismometer in the article.

This is nothing new. Fiber has been used for years in various detection systems from long perimeter fences where it will alarm for intruders trying to climb over, to downhole drilling where fiber loops detect pipe break locations in oil & gas wells. It's detecting vibration and you can get this down to within a few meters along a +/-2km run if I remember correctly.

Actual paper:

https://www.nature.com/articles/s41586-023-06227-w.epdf

Unfortunately not available as nonDRM PDF from scihub.

What about gravity waves? They're very long and so maybe they could pick up something?

The only major cost to this kind of network of fiber cables is: digging trenches.

That is, if you are deploying a greenfield of fiber optic grids.

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