Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dark fiber lays groundwork for long-distance earthquake detection and groundwater mapping

06.02.2019

Berkeley Lab researchers capture a detailed picture of how earthquakes travel through the Earth's subsurface

In traditional seismology, researchers studying how the earth moves in the moments before, during, and after an earthquake rely on sensors that cost tens of thousands of dollars to make and install underground. And because of the expense and labor involved, only a few seismic sensors have been installed throughout remote areas of California, making it hard to understand the impacts of future earthquakes as well as small earthquakes occurring on unmapped faults.


By coupling DAS technology with dark fiber, Berkeley Lab researchers were able to detect both local and distant earthquakes, from Berkeley to Gilroy, California, to Chiapas, Mexico.

Credit: Ajo-Franklin/Berkeley Lab


A research team led by Berkeley Lab's Jonathan Ajo-Franklin ran their experiments on a 20-mile segment of the 13,000-mile-long ESnet Dark Fiber Testbed that extends from West Sacramento to Woodland, California.

Credit: Ajo-Franklin/Berkeley Lab

Now researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have figured out a way to overcome these hurdles by turning parts of a 13,000-mile-long testbed of "dark fiber," unused fiber-optic cable owned by the DOE Energy Sciences Network (ESnet), into a highly sensitive seismic activity sensor that could potentially augment the performance of earthquake early warning systems currently being developed in the western United States. The study detailing the work - the first to employ a large regional network as an earthquake sensor - was published this week in Nature's Scientific Reports.

Shaking up seismology with dark fiber

According to Jonathan Ajo-Franklin, a staff scientist in Berkeley Lab's Earth and Environmental Sciences Area who led the study, there are approximately 10 million kilometers of fiber-optic cable around the world, and about 10 percent of that consists of dark fiber.

The Ajo-Franklin group has been working toward this type of experiment for several years. In a 2017 study, they installed a fiber-optic cable in a shallow trench in Richmond, California, and demonstrated that a new sensing technology called distributed acoustic sensing (DAS) could be used for imaging of the shallow subsurface. DAS is a technology that measures seismic wavefields by shooting short laser pulses across the length of the fiber. In a follow-up study, they and a group of collaborators demonstrated for the first time that fiber-optic cables could be used as sensors for detecting earthquakes.

The current study uses the same DAS technique, but instead of deploying their own fiber-optic cable, the researchers ran their experiments on a 20-mile segment of the 13,000-mile-long ESnet Dark Fiber Testbed that extends from West Sacramento to Woodland, California. "To further verify our results from the 2017 study, we knew we would need to run the DAS tests on an actual dark fiber network," said Ajo-Franklin, who also heads Berkeley Lab's Geophysics Department.

"When Jonathan approached me about using our Dark Fiber Testbed, I didn't even know it was possible" to use a network as a sensor, said Inder Monga, Executive Director of ESnet and director of the Scientific Networking Division at Berkeley Lab. "No one had done this work before. But the possibilities were tremendous, so I said, 'Sure, let's do this!"

Chris Tracy from ESnet worked closely with the researchers to figure out the logistics of implementation. Telecommunications company CenturyLink provided fiber installation information.

Because the ESnet Testbed has regional coverage, the researchers were able to monitor seismic activity and environmental noise with finer detail than previous studies.

"The coverage of the ESnet Dark Fiber Testbed provided us with subsurface images at a higher resolution and larger scale than would have been possible with a traditional sensor network," said co-author Verónica Rodríguez Tribaldos, a postdoctoral researcher in Ajo-Franklin's lab. "Conventional seismic networks often employ only a few dozen sensors spaced apart by several kilometers to cover an area this large, but with the ESnet Testbed and DAS, we have 10,000 sensors in a line with a two-meter spacing. This means that with just one fiber-optic cable you can gather very detailed information about soil structure over several months."

Digging deep for data underground

After seven months of using DAS to record data through the ESnet Dark Fiber Testbed, the researchers proved that the benefits of using a commercial fiber are manifold. "Just by listening for 40 minutes, this technology has the potential to do about 10 different things at once. We were able to pick up very low frequency waves from distant earthquakes as well as the higher frequencies generated by nearby vehicles," said Ajo-Franklin. The technology allowed the researchers to tell the difference between a car or moving train versus an earthquake, and to detect both local and distant earthquakes, from Berkeley to Gilroy to Chiapas, Mexico. The technology can also be used to characterize soil quality, provide information on aquifers, and be integrated into geotechnical studies, he added.

With such a detailed picture of the subsurface, the technology has potential for use in time-lapse studies of soil properties, said Rodríguez Tribaldos. For example, in environmental monitoring, this tool could be used to detect long-term groundwater changes, the melting of permafrost, or the hydrological changes involved in landslide hazards.

The current study's findings also suggest that researchers may no longer have to choose between data quality and cost. "Cell phone sensors are inexpensive and tell us when a large earthquake happens nearby, but they will not be able to record the fine vibrations of the planet," said co-author Nate Lindsey, a UC Berkeley graduate student who led the field work and earthquake analysis for the 2017 study. "In this study, we showed that inexpensive fiber-optics pick up those small ground motions with surprising quality."

With 300 terabytes of raw data collected for the study, the researchers have been challenged to find ways to effectively manage and process the "fire hose" of seismic information. Ajo-Franklin expressed hope to one day build a seismology data portal that couples ESnet as a sensor and data transfer mechanism, with analysis and long-term data storage managed by Berkeley Lab's supercomputing facility, NERSC (National Energy Research Scientific Computing Center).

Monga added that even though the Dark Fiber Testbed will soon be lit for the next generation of ESnet, dubbed "ESnet 6," there may be sections that could be used for seismology. "Although it was completely unexpected that ESnet - a transatlantic network dedicated for research - could be used as a seismic sensor, it fits perfectly within our mission," he said. "At ESnet, we want to enable scientific discovery unconstrained by geography."

###

The research was funded by Laboratory Directed Research and Development Funding with earlier research supported by the Strategic Environmental Research and Defense Program (SERDP), U.S. Department of Defense.

ESnet, a DOE Office of Science user facility, is a high-performance, unclassified network built to support scientific research. It is managed by Berkeley Lab.

For more information, see: "Dark Fiber: Using Sensors Beneath Our Feet to Tell Us About Earthquakes, Water, and Other Geophysical Phenomena"

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab's facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy's Office of Science.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Media Contact

Theresa Duque
tnduque@lbl.gov
510-495-2418

 @BerkeleyLab

http://www.lbl.gov 

Theresa Duque | EurekAlert!
Further information:
https://newscenter.lbl.gov/2019/02/05/dark-fiber-lays-groundwork-for-long-distance-earthquake-detection-and-groundwater-mapping/
http://dx.doi.org/10.1038/s41598-018-36675-8

Further reports about: Dark Fiber Map earthquake fiber seismic activity seismic map seismology

More articles from Earth Sciences:

nachricht A Volcanic Binge And Its Frosty Hangover
21.02.2019 | Universität Heidelberg

nachricht Researchers get to the bottom of fairy circles
21.02.2019 | Georg-August-Universität Göttingen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light from a roll – hybrid OLED creates innovative and functional luminous surfaces

Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.

The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...

Im Focus: Regensburg physicists watch electron transfer in a single molecule

For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.

The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...

Im Focus: University of Konstanz gains new insights into the recent development of the human immune system

Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens

Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...

Im Focus: Transformation through Light

Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light

When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...

Im Focus: Famous “sandpile model” shown to move like a traveling sand dune

Researchers at IST Austria find new property of important physical model. Results published in PNAS

The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Global Legal Hackathon at HAW Hamburg

11.02.2019 | Event News

The world of quantum chemistry meets in Heidelberg

30.01.2019 | Event News

Our digital society in 2040

16.01.2019 | Event News

 
Latest News

A Volcanic Binge And Its Frosty Hangover

21.02.2019 | Earth Sciences

Cleaning 4.0 in the meat processing industry – higher cleaning efficiency

21.02.2019 | Trade Fair News

New mechanisms regulating neural stem cells

21.02.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>