The California land often shaken by earthquakes, so the experimental station of detecting earthquakes posted here. And, after a year of observations, the developers have concluded it works better than expected. A feature of the new system is that it is based on conventional optical fiber, through which, in large cities come online.

In the optical fiber light moving, Bouncing off the walls of the cable, and if this environment were the same and not subject to outside influences, the signal always had the same handwriting. In reality, due to the high speed of light the slightest vibration, the displacement of the cable, etc. create interference. All you need to supply sensors for their tracking in the oil and gas industry, this technology is called “distributed acoustic sensing”.

Stanford scientists put underground for 4.8 km of optical fiber in the form of eight, put ultra-sensitive laser detectors and launched a continuous signal. From September 2016, this optical-seismic laboratory recorded 800 shocks of the earth from explosions in the local quarry, to the devastating earthquake in Mexico this year. Both earthquakes, though they happen to delete 3220 km from the station.

The accuracy of the measurement of the tremors of the earth in such technology is inferior to traditional seismometers, but its advantage is that fiber is already laid in many places. A simple detector laser oscillation light in the cable is less than $1 – if set their tens of thousands, we get a giant passive monitoring system activity of the Earth. And it does not affect the operation of communication systems.

The signal recorded at Stanford opticalmechanical Observatory on 8 September during the devastating earthquake in Mexicanaclick — Stanford University