Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right nowTVBNOW 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 f" g& ?( D* d0 [. n+ 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.
2 e+ J6 ^* r* W. Y8 o5 k) xA '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.
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& o* c0 J. d" X, I8 c+ ^/ s2 {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.
8 ]* o- K/ \. _5 gTVBNOW 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。5 {! u7 {7 S" Y5 w
4 k& ~& k+ A- p; uTVBNOW 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。Eruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believed
, M, ]% X" U4 x: A+ L9 f公仔箱論壇Supervolcanoes are fuelled by giant pools of magma that form deep underground.tvb now,tvbnow,bttvb1 o I* H0 I) [. R0 w
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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.5.39.217.76& ]! V2 P2 F Z( Y7 A, l
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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.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 g5 r6 D/ r4 E. z5 A, u/ V
0 Z. ^) d0 o4 S9 k7 etvb now,tvbnow,bttvbA magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.5.39.217.764 a- B( }. s) C
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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.
' Q8 t2 ] k$ g( X# Q% S; YTVBNOW 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 x V# w! p C! ptvb 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
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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 uninhabitable5.39.217.766 F4 @, e. o9 {' _3 f
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8 s" B3 Z# _7 e6 R3 LCastle 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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% W) |( @& _# u. k' 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。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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{6 m0 K; z, D, TA 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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$ L2 y3 u! r* `& w1 M公仔箱論壇The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.
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; x, K, `6 W* O8 {) uTVBNOW 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。
6 \* C" w* r6 R* |* qtvb now,tvbnow,bttvbSeveral 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.. K. ~% P: x. G# w1 z d6 A, L
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: r7 c4 a- t0 j u$ H" C" M, t% xThe 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.
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5 d5 e% @2 ?6 s* p% h: s5.39.217.76The research is published in the online journal Public Library of Science ONE.
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Lead 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.公仔箱論壇' K# _( Q H2 s6 @# s/ [$ C
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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。/ c9 B! t! H$ x- p; x# R. m3 Z" r
‘The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.’
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# L0 Z6 |$ m! r8 O8 l7 L6 vHe 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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