Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
2 l( K4 V& D% Q# e, m7 u公仔箱論壇- 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.
: Z9 q5 N2 l6 f; H H: Y/ OA '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.8 o( |" n! U6 u8 R# O9 _! \ e
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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 T; S, o- {8 n7 z$ x9 t2 E
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8 M- T. b7 _# o) Q9 Vtvb now,tvbnow,bttvbEruption: 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。. V+ _% f! n* u& A6 D! ~' I
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.5.39.217.76. V# c/ n" z) U: ~. Z- x% H' {. A
8 {- B$ V3 H7 QBut the new study suggests that the giant magma bodies may only exist for a few thousand years, or even a few hundred, before exploding.5.39.217.76# m& p: | q, T
; G9 l3 y# a7 B- K5 C( C公仔箱論壇A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.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 B2 P8 D* F9 x- r" V! i# s3 K% M# D
6 s" X9 `" b) V& P c7 d, b7 B( x5.39.217.76The 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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8 T- w' f0 W* s: x3 gBlobs of magma occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone Caldera.5 C" @2 X( _7 a l5 ~
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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 uninhabitable: ]) |. e8 d! U, }' k
7 h& f. O1 A! @, _6 o+ JTVBNOW 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。
: X+ G/ V# n) g3 x+ b3 Ltvb now,tvbnow,bttvbCastle Geyser and sunrise Yellowstone National Park Wyoming: Researchers now believe that the huge 'supervolcano' beneath the park is far more active than previously thought公仔箱論壇' B# c* Q" Y6 v( b" f% U" \, Y- [
5 M2 B/ ^: g% ] f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.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 T# {, c" Q* u0 _* V
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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.
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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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' Y9 v5 p) \* F: c2 T/ GThe 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.' t$ G3 Y, p# n- V
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! ~( F$ n3 {; ?3 wtvb now,tvbnow,bttvbThe 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.5.39.217.76# `- P# ~! Y: q1 Z3 E; q0 W7 i8 G
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4 \7 g0 u* k3 N5 }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.5.39.217.763 {* I! u0 e' k, [$ [: b
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7 Y) L; P* `9 ^4 K/ z# F‘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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# v. _9 @7 t$ C5.39.217.76He 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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