Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
: ?! `8 c5 x0 u. A. T/ y4 p5.39.217.76- 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. ' x( [$ S; v. ~# h( O4 V/ T
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Instead of the process taking hundreds of thousands of years, it could take just hundreds.
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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.tvb now,tvbnow,bttvb) c" a. ?3 Q. }7 V _! x8 N
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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 believedtvb now,tvbnow,bttvb6 s5 Y ~0 v: n2 n
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.tvb now,tvbnow,bttvb6 e5 \# o7 G, B% l9 l4 u& T
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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,bttvb" U4 ~3 j( ^$ ~9 Y% O# ?' f+ o3 r
- D( R% A- w' R+ p4 FA magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
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4 s9 R4 d# _" ?( _8 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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Blobs of magma occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone Caldera.5.39.217.767 J, s/ ?# u/ s; r# d# n
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5 K+ O7 b) `/ m6 i% ~9 N- VTVBNOW 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。Steaming Mud Volcano at Yellowstone National Park in winter. Researchers now believe that the supervolcano beneath the park could be more active than thought tvb now,tvbnow,bttvb6 M2 u# ~6 p' g: Q5 `, P+ w
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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 uninhabitabletvb now,tvbnow,bttvb( }, F) @. z8 n. j9 P$ ?+ B9 W$ g
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* p: ?5 W. ? l: B7 N7 qCastle Geyser and sunrise Yellowstone National Park Wyoming: Researchers now believe that the huge 'supervolcano' beneath the park is far more active than previously thoughttvb now,tvbnow,bttvb8 n* X4 ?$ c0 W3 P" y
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Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.tvb now,tvbnow,bttvb: f; \4 Q% J# f& p) E& c
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/ _% [9 M8 ~; ?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。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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# j# p: l, F9 X/ g$ R/ G% t5 c5.39.217.76A full scale eruption at Yellowstone would be 1,000 times more powerful than the volcanic blast that tore apart Mount St Helens in 1980.5.39.217.764 d5 d4 L. l$ l% y
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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.% h9 Q/ G9 ]7 R9 V# c8 H
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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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9 | d% Z+ b9 [& e! h7 i' U3 stvb now,tvbnow,bttvbSeveral 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.
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, I2 [9 l2 k) C; j% f3 UThe 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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; Q2 n1 A1 y- ?& m公仔箱論壇The research is published in the online journal Public Library of Science ONE.
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3 q1 A: Y7 _) A! R4 k2 {7 |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。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.; t: E' B& e8 F$ j* `5 y9 r! ?
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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.’公仔箱論壇' ~; `1 V) E, z: n
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8 S5 l: q( X; n+ V9 i; v% s- M公仔箱論壇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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