Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
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- 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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4 Z. t) Z0 ]& X$ a, V公仔箱論壇Instead of the process taking hundreds of thousands of years, it could take just hundreds.www2.tvboxnow.com5 P( \7 O8 C$ |3 U4 D/ G; @. a
. c+ i V i' ]& M ]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) y- |# g# a/ A8 _6 [* o1 S0 C
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' V @$ e0 Q3 H* n. G& E% C* |tvb now,tvbnow,bttvbEruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believedwww2.tvboxnow.com5 `' s2 E$ v2 y
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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5 o8 g: l& `6 S6 s公仔箱論壇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.tvb now,tvbnow,bttvb6 w, q/ I- b! p- C0 C
( O4 ?! s; o9 x. k J3 F( utvb now,tvbnow,bttvbA 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。3 t# ^" k3 W! s2 q$ b* E( U
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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." D$ R! n' P; X2 L; N X
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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
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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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/ q' \# @* n1 `( [5 W) }" O公仔箱論壇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.( }5 J9 N3 ]( K# Z. T- v
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5 d2 ^) @2 i5 C& A1 M7 h" mwww2.tvboxnow.comThe supervolcano has erupted a total of three times in the last 2.1 million years. Scientists believe it could be due to erupt again., s1 a; L; o% o& L5 d8 G7 K @
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& H7 i4 ?# n' ]2 f4 `+ j; L6 E& }tvb 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.www2.tvboxnow.com* `# N4 n. `4 H' h" W, Y2 ]) q
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+ S7 @+ K0 a4 wThere 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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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.) S/ Y- T' U4 p( ?$ t( n! k r
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: s7 t0 y4 y# n4 D8 AThe 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.7 w* n) ^- G9 Y* p2 |; |# c
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The research is published in the online journal Public Library of Science ONE.
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9 N; U! _# w$ L9 DLead 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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‘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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