Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now5.39.217.769 B, O# Z# u: T' O
- 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.
1 s i" K" A" S' y公仔箱論壇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. 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。, g6 O! Q$ ?* m! [* H* k" \
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Instead of the process taking hundreds of thousands of years, it could take just hundreds.4 U; k% s" w/ s* b
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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.
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7 k/ l9 x- S3 JEruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believed
B8 R+ B9 y; Y! W. X \% g5 CTVBNOW 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。Supervolcanoes are fuelled by giant pools of magma that form deep underground.
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Geologists had thought it took between 100,000 to 200,000 years for a supervolcano magma pool to build up enough pressure to erupt.公仔箱論壇( }2 i2 Y, R+ S1 u
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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, w; P: E( @- G$ e3 b) c
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Blobs 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。) [0 o: j7 W7 W
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* R8 s: Z2 G$ k& `) aTVBNOW 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公仔箱論壇4 H$ N8 d: R0 q! m6 j7 Q
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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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) J% m @, u$ X! X. G5 v7 M公仔箱論壇Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.3 b2 F2 y3 m8 {4 ~
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$ ~* e' b; P$ l" q; h6 G* I/ J公仔箱論壇The supervolcano has erupted a total of three times in the last 2.1 million years. Scientists believe it could be due to erupt again.
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3 a% v+ y4 q! c) V. C3 m公仔箱論壇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.
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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.
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# ?) V& r/ ~! z) A, j L5.39.217.76The 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.: O4 N: X, }# U- z6 E! Z. @/ \
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The research is published in the online journal Public Library of Science ONE.5.39.217.76. W& ]* Z4 D7 N( b4 h2 w
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- m7 d1 h* A/ w1 d4 aLead 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.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。 v$ d9 w: m+ H4 j
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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.’
! [' ]% n+ f0 c2 |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。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。2 o/ |3 G# W6 p- [" V$ O
& w* {2 W+ J* d+ K5 \$ DTVBNOW 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。He 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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