In addition to high-speed data transmission, fiber optic networks can also be useful in other contexts. This is what Open Fiber is experiencing with the MEGLIO project, an Italian scientific program aimed at creating an innovative system for monitoring seismic waves thanks to Fiber Sensing that allows continuous measurements in real time on an entire stretch of fiber optic cable .
MEGLIO stands for Measuring Earthquakes signals Gathered with Laser Interferometry on Optic Fibers, and the first results of the project in question were presented in recent days in Ascoli. The optical fiber section used is the one that connects the Point of Presence (PoP) of Ascoli Piceno and Teramo.
In addition to Open Fiber, the National Institute of Geophysics and Volcanology (INGV), the National Institute of Metrological Research (INRiM), Metallurgica Bresciana and Bain & Company are also participating in the experiment.
“ It's about improving monitoring and obtaining information from territories currently excluded from our network of seismographs, ” explains Herrero. It is also curious that seismographs are no longer able to measure above a certain magnitude threshold, while the fiber – considering its sensitivity range – is still able to perceive variations.
The details of the experimentation that uses optical fiber
The whole trial lasted two years. During the initial phase, interferometric laser sensors were built which, during the month of June 2021, were installed close to the fiber optic network that connects the two aforementioned locations, considered by INGV of greatest scientific interest for the project in question.
The sensors have thus already produced huge amounts of data that are available on the Open Fiber servers and under analysis by Bain & Company. The latter, thanks to some mathematical algorithms applied to the data, is cleaning the useful impulses from noise in order to make them usable in turn by the National Institute of Geophysics and Volcanology to finally characterize the presence of seismic phenomena.
It is therefore the first time in the world that such a project has been carried out, that is the use of optical fibers in a terrestrial context for earthquake monitoring. It is an environment rich in noise, because it is also located in an urban environment, on a commercial network that also carries data from the exchange of information via the internet.
The advantages of using these connections is that the optical fibers are immune from electromagnetic disturbances, can withstand a wide range of temperatures (from -100 ° to 300 °), high pressures (10,000 psi), and mechanical stress, the all without disturbing in any way the current use for internet communication.
In fact, traditional seismographs are systems distributed throughout the territory. There are about 500 to date and are connected to the network via radio. In a nutshell, this translates into high management and maintenance costs, and interference risks.
Obviously, no one expects to be able to predict earthquakes , but such technology could represent an Earthquake Early Warning (EEW) system. This means that it may be able to signal impending earthquakes before the actual seismic waves arrive.