Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
* }1 E) H# y4 Z: y- Most deadly event that can hit Earth short of asteroid
- Scientists believed they took 100,000 years to build up
- Instead, figure could be just hundreds
- Supervolcano believed to be simmering under Yellowstone in U.S.
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A 'supervolcano' eruption is the most catastrophic natural disaster that can hit our planet, short of an asteroid impact - and now scientists believe they may build up a deadly head of steam far faster than we thought. , P# A8 g, c7 }0 H( t" D; }
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Instead of the process taking hundreds of thousands of years, it could take just hundreds.
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The news could be bad for the US, where a supervolcano is said to be simmering beneath Yellowstone National Park. If it erupted, two thirds of the country could be rendered uninhabitable.公仔箱論壇" W8 f* v' e, w, n, s
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Eruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believedtvb now,tvbnow,bttvb1 W* N( D1 e$ s) V4 R: E( \; Q6 r1 H
Supervolcanoes are fuelled by giant pools of magma that form deep underground.公仔箱論壇0 _# n, q' K6 X! C* ~
- @% ^/ a, P! R1 k8 U( _. [3 }TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。Geologists had thought it took between 100,000 to 200,000 years for a supervolcano magma pool to build up enough pressure to erupt.
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But the new study suggests that the giant magma bodies may only exist for a few thousand years, or even a few hundred, before exploding.
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A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
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The Wyoming park sits above a gigantic plume of hot and molten rock that begins at least 400 miles beneath Earth's surface and rises to 30 miles underground, where it widens to about 300 miles across.公仔箱論壇- t% V1 a4 H* N- o. C' \* [& Y# p) h
# Q% Z$ N2 `: ktvb now,tvbnow,bttvbBlobs of magma occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone Caldera.
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Steaming Mud Volcano at Yellowstone National Park in winter. Researchers now believe that the supervolcano beneath the park could be more active than thought TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。. T& d/ g7 f/ p+ h1 d
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( k; [3 H# m# \. l/ T# ]7 o* oTVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。The news could be bad for the US, where a supervolcano is said to be simmering beneath Yellowstone National Park. If it erupted, two thirds of the country could be rendered uninhabitable
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Castle Geyser and sunrise Yellowstone National Park Wyoming: Researchers now believe that the huge 'supervolcano' beneath the park is far more active than previously thought
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Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.
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! F1 B5 g% P' Ftvb now,tvbnow,bttvbThe supervolcano has erupted a total of three times in the last 2.1 million years. Scientists believe it could be due to erupt again.TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。3 |1 Y+ q8 h) H$ W* `6 w H
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A full scale eruption at Yellowstone would be 1,000 times more powerful than the volcanic blast that tore apart Mount St Helens in 1980.TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。! a+ G& y8 D$ [' Q$ e% P% C
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There is evidence that a similar super-eruption in Indonesia 74,000 years ago came close to wiping out the entire human species.5.39.217.76; n4 W8 a7 @3 C
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. X5 r" { Y+ U) O; v+ C. C" S7 w" STVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.
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Several independent lines of evidence indicated that the magma pool erupted within a few thousand years, perhaps within a few hundred years, covering half the North American continent with smouldering ash.
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The scientists based their estimate on quartz crystallisation rates. Previous studies have relied on the growth of zircon crystals, which is said to be a less accurate method.4 H U: Z- Z$ D" T9 s
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The research is published in the online journal Public Library of Science ONE.2 w4 b6 l- ~8 B& L
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. `1 u) C* L n [0 ULead scientist Dr Guilherme Gualda, from Vanderbilt University in Nashville, Tennessee, said: ‘Our study suggests that when these exceptionally large magma pools form they are ephemeral and cannot exist very long without erupting.! o1 Y4 I1 d+ c; ~2 f7 A
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‘The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.’5.39.217.76/ O+ P0 Y% N8 U6 P+ K4 a$ P1 Q! s; P
TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。- @+ _8 q; W8 z2 z# o: h
) D) |; j j0 k' m! U6 \tvb now,tvbnow,bttvbHe said regions such as Yellowstone should be monitored regularly to provide advance warning of a catastrophic super-eruption. |
發表於 2012-6-1 01:50 AM
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發表於 2012-6-1 08:11 PM
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