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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Instead of the process taking hundreds of thousands of years, it could take just hundreds.4 T1 ?# Z7 e o3 _
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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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Eruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believed公仔箱論壇2 B! D* F9 P. A4 P: 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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) K! n' V# w2 m5 {8 Z6 ^- 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.
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6 y/ {% F! ~2 O4 [8 A- ? YTVBNOW 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。A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.5.39.217.76( z" f( k* a, K5 z
. x7 S5 O [' c% lThe 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." Y; |- n- ]$ x
" P3 M+ H9 ]% ~3 m! P; Otvb 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.2 Q: o! m; \' M7 ?* K
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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 uninhabitableTVBNOW 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。 w- d r/ h) s4 z2 H$ R+ @
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. ~5 }4 s& q" vtvb 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 thought7 ]# u, q5 E2 z. z
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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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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.5.39.217.765 h* G( W2 o3 @! {( M
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The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.1 k0 P$ Q' h( g" G Z- ?- c
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& d( O: r6 k; S# A) a公仔箱論壇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." Z8 G, h; D' q
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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.& `5 ?2 O+ n' d
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& [" B4 z5 A1 _8 m5.39.217.76The research is published in the online journal Public Library of Science ONE.
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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.
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. F3 L3 X" E* K5.39.217.76‘The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.’5.39.217.767 ]$ ^3 ^6 S; y M9 u# T
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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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