Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
; k2 O( V( [' W0 P- 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.
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Instead of the process taking hundreds of thousands of years, it could take just hundreds.
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, [8 A% K- s' ~' F( ]5.39.217.76The 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.5.39.217.76- a3 i8 a9 l8 b+ M& P% @7 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 believed
% B2 n( O7 }5 Z, @4 uSupervolcanoes 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.
2 |- V' G1 C& T9 `3 g公仔箱論壇公仔箱論壇- Q( ^+ r; R R7 B8 m/ R+ x
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.公仔箱論壇% `0 f( z& {- g1 S9 Q
( ^( h' `. C. ?# ?A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
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: O/ J- c% f5 P% P4 H$ c8 l公仔箱論壇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.
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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.tvb now,tvbnow,bttvb# f: _0 x) K" Y& J* w. W! R3 n* b
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X, c+ u' I" O3 T( s: ?tvb now,tvbnow,bttvbSteaming 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 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.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 \& Q M: a- Z f) _
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, H" f* f' c% r; A+ Z! 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。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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% b6 V8 w2 t: ]3 w. T, c$ S" utvb now,tvbnow,bttvbA 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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8 [1 }; C* y. rTVBNOW 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。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 V2 f% ?) v5 K. B( B! E
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4 S# c: g% C) s: `4 K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. s2 m |. z/ D- d* [4 C
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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.3 G$ p: j1 n2 x" f0 L
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. s# v6 A/ N0 OThe 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.- e" v$ ~/ ]8 [
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/ A. R1 L; c9 Y2 _- C9 M) k8 kThe research is published in the online journal Public Library of Science ONE.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。9 z9 p' z9 R: @% |; W
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/ y6 D: f" y6 yLead 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.
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" l% N7 l a6 `7 `8 ^& i1 d公仔箱論壇‘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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9 a! B/ ~+ k* F; F# PHe 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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