Nature never acts without warning; it is we who often fail to pick up the signals. In the case of volcanic eruptions, there are many signals (vibrations, deformations of the ground, movements of magma) but capturing them together, and with precision, has been impossible until now.
An international project is changing the rules of the game in the Reykjanes Peninsula, Iceland, using a technology called Distributed Acoustic Sensing (DAS). And it’s fascinating how something seemingly far away from volcanoes (a simple fiber optic cable) turned out to be the perfect tool to spy on them. Let’s see together what it is.
Fiber optics that listen to magma
There’s something poetic about the technology in question, if you think about it. The same cables that carry our messages, our photos, our streams and our data could save our lives. The DAS (Distributed Acoustic Sensing) system installed on the Reykjanes Peninsula It works by directing lasers through underground fiber optic cables. As the ground vibrates due to magma movements, these vibrations affect the laser’s path, creating a “phase change” that researchers can measure and interpret.
I'm struck by how quickly everything was implemented. Jiaxuan Li, first author of the study published in Science and geophysicist at the University of Houston, said that It took just 10 days to install the system on a 100-kilometer-long cable after a significant magmatic intrusion event on November 10, 2023. About a month later, the system recorded its first eruption. Not bad for a project that could revolutionize volcanic safety.
But the real stroke of genius lies in the use of existing infrastructure. There is no need for expensive dedicated systems; existing and unused cables are enough to create a widespread surveillance network that has no equal in terms of precision.
The Invisible Dance That Precedes Disaster
How exactly does this advance notice system work? As magma begins to rise toward the surface, it compresses and deforms the overlying ground. Sensors in the cables can measure these changes much more accurately than traditional GPS systems or satellite imagery.
What amazes me most is that the data collected They could give a half-hour's warning, in some cases even a few hours before the eruption. I can confirm that half an hour may not seem like much when it comes to natural disasters, but in some cases it can be very useful to evacuate a risk area. Think of Grindavík, the Icelandic town that had to evacuate repeatedly due to recent eruptions. For its inhabitants, those 30 minutes could mean the difference between losing or saving personal belongings, memories, and in some cases pets.
The system has already proven its usefulness by helping seismologists better understand the behavior of underground magma, which is no small feat, considering that Iceland is entering a period of more frequent eruptions.
A Global Network of Sentinels Against Volcanic Eruptions
As I write this article from Campi Flegrei, the active volcanic area of Naples where I live, I can't help but think how useful a similar system would be here. Or on Vesuvius, another "bulky neighbor" of our house. Or even in Yellowstone, in the United States, where a supervolcano sleeps under a natural paradise. Will we ever see these "spy cables" there too?
The beauty of this volcanic eruption warning technology is its scalability. Anywhere there are fiber optic cables and active volcanoes, a DAS system could potentially be deployed. It makes me think how much easier it would be for millions of people living near active volcanoes to sleep if they knew they had a reliable warning system.
Zhongwen Zhan, geophysicist of the California Institute of Technology whose lab conducted the research, stressed that there is still much work to be done and that every volcano is different. But DAS technology offers a new ability to see things that were previously invisible. He also highlighted how the project is a great example of the power of international collaboration.
Maybe that’s the point: fiber optics connect not only computers, but also people and skills. And in this case, it could also connect science to public safety, in a way that until yesterday seemed impossible. Because sometimes salvation lies in the simplest and most everyday things: a cable that passes under our feet could one day whisper “run” to us with enough advance notice.
