A trembling needle moves slowly over a roll of paper. If a truck rumbles by, the amplitude gets stronger. If an earthquake occurs — or if someone sets off an atomic bomb underground — the needle will vibrate even more, registering the strength and duration of the event.
This is how seismographs have worked for centuries.
Nowadays, seismometer data isn t recorded on paper. The information is transferred directly to computers worldwide in a matter of seconds, at which point earthquake researchers can analyze it.
As interconnected as it all sounds, though, a weak point remains: The seismometers are usually located at huge distances from one another, all across our globe — often hundreds of kilometers apart. Scientists are then forced to reconstruct the location and magnitude of an earthquake from the records of the nearest seismometers.
Every four meters
Now, an international team around Philippe Jousset and Thomas Reinsch from the German Research Center for Geosciences (GFZ) have developed a new approach to measure vibrations — using conventional fiber optic data lines.
On the peninsula of Reykjanes in Iceland, they sent laser pulses through a 15-kilometer (nine-mile) data transmission cable that is used for telecommunications there.
This cable runs over a known fracture zone between the American and Eurasian continental plates. In order to obtain comparative data, the researchers also installed a dense network of seismometers in the area.
But what they saw using the cable surprised them.
"Our measurements using fiber optic cables depicted the ground far more accurately than ever before," Jousset reported. He added that it was as if a seismometer had been installed every four meters.
