When an earthquake hits or a volcano erupts, scientists traditionally record the shaking using a specially designed instrument called a seismometer. These sensors are extremely sensitive, but they’re also expensive and distributed unevenly around the world. So scientists are working on another strategy to monitor earthquakes: using fiber optic cables—like the ones that form the backbone of the internet.
當地震來臨或火山爆發時，科學家通常會使用專門的地震儀器來記錄震動。這些傳感器是非常敏感的，但它們也是非常昂貴的，而且在世界各地分布不均衡。因此，科學家們正在制定另一個監測地震的策略：使用光纖電纜來預測地震。
「So the motions are very clear. Specifically, you can see the arrival of different bits of the seismic energy from the location at which the earthquake occurred. So the p wave and the s wave, and the different phases that move out from the site of rupture in the earth, are used by seismologists to locate the event. And so we can detect the important pieces of information above the noise using the fiber optic cable and then, in that way, the fiber optic measurement is just as good as a seismometer.」
「所以行動計劃非常清楚。具體而言，你可以看到震源地震強度的不同點。所以p波和s波以及從地球破裂部位移出的不同階段，這些被地震學家用來定位地震。所以我們可以使用光纜檢測噪聲之上的重要信息，這種光纖測量地震的方式和地震儀一樣好。「
Nate Lindsey, a PhD student and seismologist at the University of California, Berkeley. Here’s how it works: the scientists basically take a snapshot of the fiber by shining a laser down it and measuring the photons that bounce back after scattering off of small cracks and impurities in the glass. By doing this tens of thousands of times a second, the researchers can record how the cable deforms as seismic waves pass through it.
加州大學伯克利分校的博士生和地震學家Nate Lindsey認為，以下是它的工作原理：科學家們基本上是通過雷射照射光纖來測量，在玻璃中的小裂縫和雜質散射後反射回來的光子。 通過每秒數千次的研究，研究人員可以記錄地震波如何通過電纜變形的。
So far, Lindsey’s team has tested the technique in optical fibers they installed themselves in Fairbanks, Alaska, and around the Bay Area. They got promising results. But their ultimate goal is to capitalize on the vast network of unused cables—known as dark fiber—that’s already been installed by telecommunications providers for future use. Dark fiber covers much of the country, and stretches across the ocean basins—which are hard to study using traditional seismometers.
到目前為止，Lindsey的團隊已經測試了他們安裝在費爾班克斯、阿拉斯加和灣區周圍的光纖線路。他們得到了很好的結果 但是他們的最終目標是利用廣泛的未使用電纜網絡(被稱為暗光纖) 已經被電信供應商安裝，以備將來用來預測地震。深色纖維覆蓋全國大部分地區，並且橫跨海洋盆地地區，這些地區是很難用傳統地震儀來研究的。
「To put the same sensor near a volcano that occurs offshore requires infrastructure to deploy the sensor, like a big boat. It also requires a tethered cable, a battery. The sensor has to be waterproof, obviously. It’s also very corrosive underneath the ocean, and so there’s been a limitation of our ability to study offshore volcanoes. Similarly faults. Earthquake processes are understood based on faults that are on land.」
「為了把同一個傳感器放在離岸的火山附近地區，需要基礎設施來部署傳感器，就像一艘大船。它還需要繫繩和電池。當然了傳感器還必須防水。在海洋下面也有很強的腐蝕性，所以我們研究離岸火山的能力有限。地震的過程是根據地面上的故障來推理的。
「Offshore cables could also improve earthquake early warning systems in places like the Pacific Northwest, where big, dangerous earthquakes actually occur under the ocean.「We can record that earthquake more quickly and then provide a warning that much quicker. So it might be a second or two seconds more that this fiber optic technology provides.」
「海底電纜也可以改善太平洋西北地區的地震預警系統，這些地方在海底實際上發生了大規模的危險地震。」我們可以更快記錄地震發生情況，然後提供更快的警報。所以這個光纖技術可能還要再過兩秒鐘才能實現。」
Lindsey is presenting his work this week at the fall meeting of the American Geophysical Union in New Orleans. The results were also published recently in Geophysical Research Letters. If the technique proves reliable, Lindsey says it could usher in a whole new way of studying earthquakes and volcanoes. All that dark fiber may shed light on the Earth beneath our feet.
Lindsey本周將在紐奧良美國地球物理聯盟秋季會議上介紹他的工作。該研究結果最近也發表在「地球物理研究快報上。Lindsey說，如果這項技術證明可靠，它可以引入一種研究地震和火山的全新方式。所有那些黑暗的纖維可能會在我們的地球上散發出更多光芒來。
（編輯：何瑩瑩）