iee.psu.edu/news/podcast/growing-impact-seismic-sensing-fiber-optics">latest episode of "Growing Impact" delves into research using fiber optic cables to monitor environmental changes and seismic activity. Originally funded by a 2019 Penn State Institute of Energy and the Environment (IEE) seed grant, this project explores how fiber optic technology can detect hazards like flooding and sinkholes, with significant implications for geoscience and public safety.
The research, led by Tieyuan Zhu, associate professor of geosciences at Penn State, has expanded beyond its initial success in central Pennsylvania to different locations in the U.S.
Zhu said this technology can detect minute changes in real time, offering early warnings for geohazards.
"Our research is really taking advantage of what we call the dark fiber, which are the fibers used for telecommunication but are already deployed in our cities," Zhu said. "The telecommunication industry has already spent billions of dollars to put cable everywhere in cities all around the world. If we could combine existing infrastructure for geophysics sensing research, it was going to provide a great deal of research in urban cities."
The technology works by sending continuous laser signals through the cables. When disturbances such as ground strain occur, the cable scatters the laser signal back to a receiving unit. Researchers analyze this data to determine the nature, location and intensity of the disturbance. The first significant signal captured by the team was a thunderstorm moving across central Pennsylvania.
"That's never been achieved in the meteorology community," Zhu said. "It's because their meteorology sensors are two kilometers away. Across all of State College, they only have one or two sensors."
A system using fiber optic cable as the sensors provides dense, real-time data collection that provides more data compared to traditional sensors that are sparse and spaced far apart.
In addition to thunderstorms, the technology has detected seismic events such as flooding, sinkholes and human movement. Zhu emphasized it has potential for monitoring earthquakes and landslides as well.
He said this is because sensors, generally, collect data periodically whereas this technology collects data continuously. Moreover, it can sense even the smallest changes, such as permafrost melting, which Zhu and his team are using this system to monitor in Alaska.
"Even if you have a very small environmental change, the sensitivity of the laser can still detect these small changes," Zhu said. "For example, permafrost degradation, you cannot see that. In the long term. you can see that. But in the short term you cannot see the degradation. But with our equipment, we can see it from our data."
"Growing Impact" is a podcast by the Institute of Energy and the Environment. It features Penn State researchers who have been awarded IEE seed grants and discusses their foundational work as they further their projects. The podcast is available on multiple platforms, including YouTube, Apple, Amazon and Spotify.
