“It has always been the case that cables are laid first, and then people start thinking of new ways to use them,” science fiction novelist Neal Stephenson wrote in cabling in 1996. “Once a cable is in place, it tends to be treated not as a technological artifact, but almost as if it were a natural mineral formation that could be mined in many different ways.”
Each wire is about the thickness of a garden hose, but for the most part it is a protective sheath around a dozen fine strands of glass, which are so pure that a mile-thick block would appear as clear as a fresh windshield. washed. Today, some three hundred cables carry ninety-nine percent of transoceanic data traffic.
Bruce Howe, an oceanographer at the University of Hawaii, has been adding scientific instruments to seafloor cables since the early 1990s. Telecommunications companies lay new cables about once every quarter of a century to avoid outages and incorporate more advanced materials. “Whenever a company decides to shut down their cable system, instead of abandoning it in place, as was done in those days, we thought science could use it,” he told me.
In recent years, Howe managed the multi-year installation of part of the ALOHA Wired Observatory, built on a former AT&T cable located sixty miles north of Oahu. He and his colleagues later wrote that the team had trouble connecting their instruments to the cable, and the facility struggled to reach its full potential, due in part to “cable and connector problems that are still all too common.”
Similar attempts to co-opt idle cables also failed. In 1998, scientists added a seismometer, hydrophone, two pressure gauges and other instruments to an outdated cable linking Hawaii and California, but the system failed after just five years. One system near Hawaii developed a short circuit six months after deployment, and another was damaged by fishing activity off the coast of Japan. Commercial second-hand garments were not the way to go.
Howe began to wonder if it was possible to incorporate scientific equipment into operating telecommunications cables, which are meticulously maintained by the companies that profit from them. He and his colleagues designed temperature, pressure, and seismology probes that would fit neatly into the cable repeaters. “The telecom people kept insisting they wanted nothing to do with us,” Howe told me. As he tells the story, they replied, “No way, because it would affect the reliability of telecommunications.” This response disappointed scientists, who then estimated that taking advantage of wireline infrastructure would give researchers data at a tenth of the cost of building their own system from scratch.
Installing a transatlantic cable takes two to three years and about $200 million, according to Nigel Bayliff, CEO of cable operations company Aqua Comms. A single repair can cost two million dollars. Any change to a working system, even a modest science package added at no cost to the cable company, could become a liability. “It’s a bit like asking for a different bathroom on the space station,” Bayliff told me. “It’s like, ‘Really, guys? Do you really want to risk the entire space station to change the toilet? ”
“The only business reason for these cables to exist, as far as we’re concerned, is data connectivity,” Bikash Koley, vice president of global networks at Google, which has laid long stretches of cable in partnership with telecom carriers. he told me. The company has no intention of adding instruments to its cables, he said.
There are also legal obstacles. Because seafloor telecommunications cables are treated as an essential public service, they receive certain freedoms under the United Nations Convention on the Law of the Sea, but the nebulous category of “marine scientific research” does not necessarily receive the same rights. same privileges. Bayliff is concerned about what might happen to telecommunications projects if they contribute to science.
“Ninety percent telecommunications, ten percent science is now a science cable?” Bayliff asked. We may not know until a first engine tests the legal waters. But he added that governments could solve this problem by requiring collaboration between companies and researchers. “Once this becomes the norm, it will happen all the time and no one will worry, because the risks will be the same for everyone,” he said.
Howe and his team eventually collaborated with the Portuguese government, which was planning to replace its aging cable system and knows something about offshore earthquakes. In 1755, a major earthquake southwest of Lisbon triggered a tsunami and devastated the capital. Tens of thousands died.
“They’re motivated,” Howe told me. “They see this in terms of not only telecom operational costs, but also human costs, and it may take governments to really balance these kinds of considerations. Companies are not going to do that.” The Portuguese government has approved the project, and Howe expects the allocation of at least €120 million to come sometime this year. The cable will connect Lisbon, the Azores and the island of Madeira; Once operational, in 2025, the motion, pressure and temperature sensors on the cable’s repeaters will serve as a seafloor science platform and tsunami warning system.
For scientists to break the deadlock with the cable industry, they needed ways to use data that already exists, without modifying submarine cables and repeaters. Marra’s fortuitous discovery showed that this was possible.
Then, in 2020, Google agreed to share light polarization measurements from its fiber-optic network with a scientific team that included Zhan and other researchers from Caltech and the University of L’Aquila in Italy. Koley told me that Google scientists were happy to collaborate, as long as they didn’t need to add instruments to their cables. “This was a dataset that you would otherwise throw away,” Koley said. “It has no other use for us.”
The researchers identified changes in polarization that occur when cables bend, twist and stretch, and compared the changes to dozens of earthquakes that seismometers detected over a nine-month period. This approach is not as sensitive as the Marra or DAS method, but does not require sophisticated technology in the form of advanced lasers. “Because the method is so easy to implement, we actually now have six or seven cables on board that provide data,” Zhan said.
Last year, Google gave Marra and her team access to a cable landing station in Southport, England, where the company used a cable that stretches to Dublin and then to Halifax, Canada. The company was willing to give researchers temporary access to certain channels when it wasn’t using them. The researchers drove five hours from their lab in Teddington and set up custom lasers and detectors, as well as computers they could access remotely. They now had the power to detect phase changes under the Irish Sea and the Atlantic Ocean.
But they still needed a way to determine where the phase changes were occurring in order to figure out the exact location of the seafloor movements. To solve this problem, the researchers took advantage of the small mirrors built into fiber optic repeaters, which typically help technicians diagnose problems along specific lengths of cable. The 128 mirrors between Southport and Halifax allowed them to pinpoint the specific part of the cable where a phase change first occurred. His approach had the potential to turn the cable into one hundred and twenty-nine localized earthquake detectors.