Scientists Using Lasers And Fiber Optic Lines To Measure Seismic Activity
Could offer scientists a better understanding and possibly an early warning system.
A new way of measuring earthquakes using lasers and telecommunication lines could offer scientists a better understanding and possibly an early warning system.
Nevada is often referred to as earthquake country, since they tend to occur frequently here in our area. In order to better understand and measure them, scientists are testing out a new method using light beams and fiber optic lines.
They are using existing fiber optic cables that are under the ground to beam pulses of light. Because these cables are so sensitive and the way light travels through them, any vibration shortens the light that will bounce back, allowing these scientists to measure the duration and strength.
“We can measure the same seismic motion on that optical fiber down to about a millionth or maybe ten millionth of a human hair -- we can measure that kind of motion on it," said Scott Tyler, Hydrology Professor at the University of Nevada, Reno (UNR).
Tyler is talking about a new technique called distributed acoustic sensing, or DAS. Instead of using sound, it measures the light and changes therein to gauge vibrations in the earth.
“We are just going to use the buried fiber optic cable that is sitting there for telecommunications to tell us something about how earthquakes will propagate," said Tyler.
This form of measurement is said to be extremely accurate: even footsteps can be registered on the data brought in.
“Fiber optic cables that are already laid out, which is also known as dark fiber, will save us a lot of money and potentially lead us to new technology and early warning across the Reno basin," said Rachel Hatch-Ibarra, PHD at the UNR Seismology Lab.
To test the accuracy of this theory, they buried a few traditional seismometers along the test route, which runs from Virginia Street along California Avenue and onto Mayberry Drive. As for the fiber optic cables, these are all existing ones previously used for telecommunication and are otherwise just going to waste.
"Instead of using thousands of geophones, we can use a single cable and collect similar information," said Elanz Seylavi, a Civil Engineering Professor at UNR.
While predicting earthquakes is a little outside the realm of possibility, if this technique was implemented across the country, it could allow for a brief warning before a large quake.
“We can start using that as an earthquake early warning system, so we can be telling you 30-40 seconds ahead of time that there's an earthquake coming and how much motion there’s going to be just by using the existing telecommunication network," said Tyler.
This is just the start -- if the data proves to be as accurate as they expect, scientists plan on taking advantage of unused fiber optic cable that already circles Reno along McCarran Boulevard.
For more information, visit the Nevada Seismological Laboratory website here.