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科学美国人60秒 SSS Big Earthquakes May Be More Likely During New and Full Moons

时间:2017-03-06 02:56:47

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Every two weeks, on the full and new moons, the sun, moon and Earth fall along a nearly straight line. The combination of gravitational forces in this arrangement creates large swings in the tides. But the celestial1 alignment2 affects more than the oceans—it also tugs3 on Earth’s crust, adding to the stress on faults. This makes it more likely that major earthquakes will strike at these times, according to a new study.

The idea isn’t new, but scientists have had a hard time testing the earthquake-tide relationship. For instance, three of the largest earthquakes in recent years happened when tidal stress was high. But those big ones are rare and the link seems to break down for smaller events.

So the researchers crunched4 a bunch of numbers: by looking at more than 10,000 medium and large earthquakes, they found that the proportion of large events increased when tidal stress was high.

The results do not imply that every full or new moon will bring an earthquake—obviously. What the findings mean is that high tidal stress during new or full moons may up the chances that an earthquake will grow bigger than it otherwise might have been.

“Even magnitude 9 earthquakes start like magnitudes 1 or 2.” Satoshi Ide, the University of Tokyo seismologist who led the study. “So, at the initial stage, it’s very difficult to distinguish small or large earthquakes. It starts similarly, but it grows at some probability to large scale. That probability is controlled by some other effect.”

And one of those effects might be the tides. Ide points out that tides in the Earth’s crust are known to cause tiny tremors5 along deep faults. “Earthquake faults are locked everywhere, but that kind of slow deformation6 unlocks very small part of the fault…so it doesn’t make large failure there, but once earthquake rupture7 starts…it can propagate very far and become very large earthquake.”

The study was published in the journal Nature Geoscience. [Satoshi Ide, Suguru Yabe and Yoshiyuki Tanaka, Earthquake potential revealed by tidal influence on earthquake size–frequency statistics]

Ide is now doing a similar analysis on earthquakes that all happened in the same geologic8 setting, like subduction zones. Perhaps that research will confirm whether heavenly bodies can take smaller shakes and supersize them.

—Julia Rosen


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1 celestial 4rUz8     
adj.天体的;天上的
参考例句:
  • The rosy light yet beamed like a celestial dawn.玫瑰色的红光依然象天上的朝霞一样绚丽。
  • Gravity governs the motions of celestial bodies.万有引力控制着天体的运动。
2 alignment LK8yZ     
n.队列;结盟,联合
参考例句:
  • The church should have no political alignment.教会不应与政治结盟。
  • Britain formed a close alignment with Egypt in the last century.英国在上个世纪与埃及结成了紧密的联盟。
3 tugs 629a65759ea19a2537f981373572d154     
n.猛拉( tug的名词复数 );猛拖;拖船v.用力拉,使劲拉,猛扯( tug的第三人称单数 )
参考例句:
  • The raucous sirens of the tugs came in from the river. 河上传来拖轮发出的沙哑的汽笛声。 来自辞典例句
  • As I near the North Tower, the wind tugs at my role. 当我接近北塔的时候,风牵动着我的平衡杆。 来自辞典例句
4 crunched adc2876f632a087c0c8d7d68ab7543dc     
v.嘎吱嘎吱地咬嚼( crunch的过去式和过去分词 );嘎吱作响;(快速大量地)处理信息;数字捣弄
参考例句:
  • Our feet crunched on the frozen snow. 我们的脚嘎吱嘎吱地踩在冻雪上。 来自《简明英汉词典》
  • He closed his jaws on the bones and crunched. 他咬紧骨头,使劲地嚼。 来自英汉文学 - 热爱生命
5 tremors 266b933e7f9df8a51b0b0795733d1e93     
震颤( tremor的名词复数 ); 战栗; 震颤声; 大地的轻微震动
参考例句:
  • The story was so terrible that It'sent tremors down my spine. 这故事太可怕,它使我不寒而栗。
  • The story was so terrible that it sent tremors down my spine. 这故事太可怕,它使我不寒而栗。
6 deformation 59ryp     
n.形状损坏;变形;畸形
参考例句:
  • The deformation frequencies are not sufficiently distinctive.其变形频率不是十分明显的。
  • The calculated deformation is almost equal to the real situation by measurement.经检测,计算变形量与实际情况基本一致。
7 rupture qsyyc     
n.破裂;(关系的)决裂;v.(使)破裂
参考例句:
  • I can rupture a rule for a friend.我可以为朋友破一次例。
  • The rupture of a blood vessel usually cause the mark of a bruise.血管的突然破裂往往会造成外伤的痕迹。
8 geologic dg3x9     
adj.地质的
参考例句:
  • The Red Sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
  • Delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。

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