Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now" D0 @6 @- X/ o$ m
- 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.
2 W/ ^+ X! D0 a9 o; 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。
1 C* j4 a& |- P0 W0 m9 tTVBNOW 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。Instead of the process taking hundreds of thousands of years, it could take just hundreds.# i/ n6 U3 V" k& O; y6 r
1 v g- e, b+ I7 |+ c- d3 Q公仔箱論壇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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! \# Y9 g& ^9 m' O/ M, g; A G7 Qtvb now,tvbnow,bttvbEruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believedtvb now,tvbnow,bttvb3 b- Y- [! m" N
Supervolcanoes are fuelled by giant pools of magma that form deep underground.: t [0 D$ |& S% r! @* F5 G
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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- S9 x/ Z' r- k8 z3 l5 L
- K% E% ^ p, f- ` \, S5.39.217.76But 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.# T- S' |: ~( Y' X) m
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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% l, _2 [ E8 b+ G- f- a, E
5 H2 ^$ B r6 k4 ~) x1 Ltvb 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.公仔箱論壇- o8 x$ d4 f& h2 b# ^
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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 / N' w C8 e5 |6 w
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。4 f" k7 e( m' u2 g7 l+ D
( q2 S9 ~0 {( F# f0 ?% W5 ITVBNOW 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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% r) d/ B* m4 h2 B4 t( L$ {- stvb 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.. b( ]5 `/ Q& a' }/ C) M) y, {# {
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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。0 ` N' u' ?: {3 } a) |
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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.
& U: N" [1 ^0 Z( p) |0 j5 q5.39.217.76tvb now,tvbnow,bttvb3 }- }7 b$ ]2 {" o+ g
, }) N4 r6 z' J* U$ BTVBNOW 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.3 Z6 V8 C; @2 f- P0 s
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% R+ h# ] Q/ w; B" FTVBNOW 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 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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The research is published in the online journal Public Library of Science ONE.
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6 }: @) N3 b7 [' c- g% zLead 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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" J8 h' \/ s" {5 |tvb now,tvbnow,bttvb‘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 t. Y ^& i f5 z! q1 M3 ~7 b0 F
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. J. Q: n" `4 \& m/ [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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