Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
3 W4 q4 \6 n# Z- f) QTVBNOW 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。- 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. tvb now,tvbnow,bttvb' h. G2 z* P* f7 w* N. Z+ ~
5 J1 H/ O: s4 g ]( X8 b5.39.217.76Instead 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" p. t' q/ Z# P2 d
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8 _: t2 F& N& c* ETVBNOW 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 believedTVBNOW 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。+ f$ y. Q& }) ]8 b% D
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.
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/ J Q4 b: y* \tvb now,tvbnow,bttvbBut 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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( U6 I- k, `% g% W7 b5 X6 u1 D; etvb now,tvbnow,bttvbThe 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+ v: x5 k/ q y( 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。" D* n. [2 \6 V- Z: `3 o
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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 uninhabitabletvb now,tvbnow,bttvb/ b7 v U' p8 U$ L) z/ [
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+ ^. z: a7 C+ M* D, 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/ T/ T) ?( r# Y: `( R$ B
$ ]: |. T, u, K, l! f3 B7 Btvb now,tvbnow,bttvbResembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.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。; @( J9 i2 o/ I
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# X2 P) \: F( |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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A full scale eruption at Yellowstone would be 1,000 times more powerful than the volcanic blast that tore apart Mount St Helens in 1980.0 y/ B1 J$ g# r) U' Q# y3 O0 l
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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.公仔箱論壇. w) N1 G8 U3 p+ H2 K2 ^% c: I
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- @( \/ C# R# u0 nTVBNOW 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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3 g7 v1 J& e8 ^0 _ n3 vSeveral 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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q9 b5 Z) |8 E, L4 eThe 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.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 y3 r' M! T# Z3 {; d, e5 |5 l2 w6 h0 ?
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The research is published in the online journal Public Library of Science ONE.$ z/ j+ c5 A5 s& I) f+ R4 i1 J# W" l
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' ]1 B% x7 n; w2 m9 K5.39.217.76Lead 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。3 ~7 m) q/ W: \7 Y1 t& W
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5 e5 C" {2 }; X' xTVBNOW 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 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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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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