FibreSense have commercialised hardware and software that does just this in an insane amount of detail, it’s very cool

https://fibersense.com/

Not affiliated, just a fan

Yes, you can. This was first used by the Navy to record / detect submarines, many decades ago.

You can also use the cable for distributed temperature sensing (some of my research used this).

There’s a network under Melbourne [0] that’s in use for research what’s possible for city scale sensing. Seems to be an option for seismology, traffic, rainfall, drainage etc.

[0]: https://www.rmit.edu.au/research/centres-collaborations/mult....

I was listening to a YouTube ( I think it was 60 minutes of all things ) where volcanologists are burying them deep down in icelandic volcanoes to help detect when volcanoes might blow. Sensing the underground magma movement..

They’re definitely used to detect earthquakes and such.

Lots! https://lunainc.com/solutions

Gyroscopes, accelerometers, and magnetic field sensors