Earthquakes detectionLong-distance earthquake detection

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.

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 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, relics of the dot-com boom when telecom companies rushed to install vast networks of underground cable to meet the demands of a growing new industry. As the technology for transmitting data improved, however, fewer cables were needed, leaving behind a legacy of unlit dark fiber, waiting to be used.