Many miles from the west coast of the Americas, a submarine cable connects Los Angeles, California with Valparaiso, Chile. It has been stretched from end to end equal to four fifths of the diameter of the earthThe cable is fiber optic; it is a lifeline for data sent between the two continents. But according to new research, the cable could easily serve a double function: mitigating the disastrous consequences of earthquakes and tsunamis.
The results are the result of an interdisciplinary collaboration between geophysicists and network engineers who looked at disturbances in the polarization of light transmitted through the cables. A patent has been filed for that of the team paper on the subject, published on Wednesday in the journal Science.
“There are scientific and societal implications here,” said Zhongwen Zhan, lead author of the new paper and a geophysicist at California Institute of Technology, in a video call. “Most of our geophysical sensors for detecting earthquakes and studying what the Earth’s interior looks like are on land, but many of the main geological processes take place in the ocean. We use existing cables in the ocean for a relatively scalable way of detecting earthquakes. We think we can use these in the future for earthquake and tsunami early warnings. “
In the relentless online world we live in, where movies filmed a century ago can be streamed at the touch of a button and you can talk in person to someone on the other side of the planet, fiber optic cables are the most affected by informational load there . Such submarine cables like Google’s “Curie” cable are constantly sending massive amounts of data at breakneck speeds to keep the world connected.
Inevitable imperfections in the cables mean that the polarization of the light varies as the data passes through it in both directions. Other disturbances, such as temperature changes and human activity, can further hinder the polarization of the cables. But in the deep sea, the temperatures are relatively constant and people are rarely there. That means that when a seismic wave ripples through the environment or a large ocean current passes through it, it is noticeably detected by how it deforms the submarine cable.
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Since seismological research at the bottom of the sea time-consuming and expensive, reading fluctuations in the polarization of such deep-sea cables is a cheap, expedient alternative, the study authors state. There are numerous submarine cables to read such data. While the Curie cable measures about four fifths of the Earth’s diameter, the total submarine cable network To orbit the planet 20 times. Between half a century of other geophysical events the team recorded, the Curie Cable discovered the magnitude 7.1 earthquake that hit Oaxaca, Mexico, last June.
When the team first recognized a fault in the cable signal and was able to align it with an earthquake, “it was not expected at all,” said Zhan. “No one had ever noticed an earthquake by looking at a telecommunication signal themselves.”
During the team’s observations, they were able to spot 20 earthquakes and 30 ocean waves. Importantly, the team is not yet able to detect the epicenter of seismic events – the cables only capture the disturbance – but Zhan said it might be possible to triangulate earthquake epicenters along the way by looking for distorted polarizations across different cables. .
“I think this will change the way we observe the oceans as seismologists,” said William Wilcock, a seismologist at the University of Washington who is not affiliated with the new paper, in a phone call. Wilcock recently wrote a Perspectives article in Science about the work of Zhan’s team. “In my area there is great concern about the Cascadia subduction zone offshore, and a lot of thought has gone into developing offshore infrastructure to improve our monitoring thereof. Hundreds of millions of dollars are needed to do this with special systems. But being able to use potentially commercial cables to do that at least in part is a huge boon to actually moving forward. “
Whether the method of listening to the Earth is broadly adopted by the telecommunications industry remains to be seen. What is certain is that this team has shown that we can listen to light, using the byproduct of your game Duty or sending family photos to spy on the planet’s seismic activity, maybe better to prepare for any small ones or very, very big will come next.