Scientists are baffled with the discovery of a cluster of faults on the ocean floor just a few miles on the southeast coast of Santa Cruz, California. Although the reports of the discovery are now published in Science, scientists are still not sure about the basic details of the faults: their size, shape, or whether or not they are active.
POSSIBLE SEISMIC ACTIVITIES
The mysterious faults were found beneath the Monterey Bay, an area that is often studied for seismic activities. The scientists who discovered these mysterious faults were quite surprised to still find new faults in the area. It could be a big problem if scientists are not able to locate seafloor faults because it can affect coastal communities during a time of earthquake, or there is a threat of a tsunami.
In the new research, scientists were able to provide a new solution to end what they call the 'tectonic blindspot.' According to an article published in National Geographic, scientists proposed to harness hundreds and thousands of miles of fiber-optic (these fiber optic cables are responsible for sending emails, tweets, and video messages across the world) and the one that made finding the mysterious faults possible.
The scientists were able to locate these mysterious faults in California by using a borrowed hose-size fiber optic cable, which served as an ad-hoc seismic array across Monterey Bay. They explained that the fiber optic cables around the major population centers can be reprogrammed as the foundation of a new early warning system in case of earthquake and tsunami. Craig Dawe of the Monterey Bay Aquarium Research Institute and co-author of the study explains, "the possibilities are pretty large. Worldwide, there's lots of fiber optic cable deployed.
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FIBER OPTICS AND SEISMIC ACTIVITIES AROUND THE WORLD
To be prepared against earthquake and tsunami, a network of seismic stations are installed across the United States. These seismic stations provide geologists with steady data about the movement of the Earth's crust hence allowing them to monitor active fault lines and identify new tremors in an instant.
However, when you cross the Pacific ocean, the number of seismic listening stations are close to none. Couple this with a patchy faulty map, and geologists are completely blind and deaf to the seismic activities underwater. Nate Lindsey, a Ph.D. candidate at the University of California Berkeley and the lead author of the study, explains, "On shore, we have this idea that we understand everything about Earth's crust. But offshore, it's like streetlights -- when you shine a streetlight on the seafloor, you see something. We just don't have very much illumination."
And brightening up the seafloor is what Lindsey and his team had in mind. The team is trying to accomplish this through an emerging technique called distributed acoustic sensing. The methodology of the distributed acoustic sensing involves shooting pulses of laser light through a fiber optic cable until it stumbles upon density variations in the glass wires. These variations, which are influenced by motion in the ground, will cause the light to bounce back towards its source. Because of this, seismologists will be able to use the patterns to spot earthquakes and new fault structures.
The research team behind this paper spent eight months developing and validating the technique through the collection of measurements using land-based cables from the United States Department of Energy in Sacramento. As of March last year, the team was able to test their methodology when the science cable of the Monterey Accelerated Research System (MARS) went offline for maintenance.
MARS would normally carry power to a deep-sea observatory, and within the four days of its maintenance, Lindsey and his team shot a laser light through the powered-down cable and were able to collect seismic data. The laser lights reached up to 12 miles and effectively creating a network of 10,000 undersea seismometers.
Coincidentally, during the test run of the experiment, a magnitude 3.4 earthquake occurred near Gilroy, California. This event caused seismic waves to ripple across the seafloor and to light up the previously unseen offshore cluster.
Lindsey and his team hope to work with MARS and use its cable for the duration of a year to be able to collect additional data on the seismic environment. According to Craig Dawe, the recent experiment was made only to illuminate a portion of the seafloor, which the MARS traverses, and hopefully, with some technological refinement, other scientists might be able to light up the entire length and discover more fault zones.
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