Scientists at Caltech Develop New Method to Detect Earthquakes

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Education is the backbone of the technical advancements we enjoy today. The inventions of the modern world rest on the shoulders of educational research endeavors and projects. In a similar way, another wave of advancements are expected in the near future as seismologists at Caltech working with optics experts at Google have developed a method to use existing underwater telecommunication cables to detect earthquakes. The technique could lead to improved earthquake and tsunami warning systems around the world.

The Science behind the Project

The optic network underlying the Earth’s oceans spread across more than a million kilometers. In the 1980s, telecommunication companies and governments began laying these cables, each of which can span thousands of kilometers. Today, the same global network is considered the backbone of international telecommunications. Zhongwen Zhan, assistant professor of Geophysics at Caltech, and his colleagues have come up with a way to analyze the light traveling through “lit” fibers—in other words, existing and functioning submarine cables—to detect earthquakes and ocean waves without the need for any additional equipment.

Zhan asserts, “We believe this is the first solution for monitoring seismicity on the ocean floor that could feasibly be implemented around the world. It could complement the existing network of ground-based seismometers and tsunami-monitoring buoys to make the detection of submarine earthquakes and tsunamis much faster in many cases.”

Operational Brilliance

The cable networks work through the use of lasers that send pulses of information through glass fibers bundled within the cables to deliver data at rates faster than 200,000 kilometers per second to receivers at the other end. To make optimal use of the cables—that is, to transfer as much information as possible across them—one of the things operators monitor is the polarization of the light that travels within the fibers. Like other light that passes through a polarizing filter, laser light is polarized. Controlling the direction of the electric field can allow multiple signals to travel through the same fiber simultaneously. At the receiving end, certain devices will check the state of polarization of each signal to see how it has changed along the path of the cable to make sure that the signals are not getting mixed. This will be an important educational venture that can change the very potentialities of disaster management.