Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
( G. ] D) {* f& F# X/ 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。- 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. os.tvboxnow.com+ n: i; ]9 \# d% A3 C' Y
& o8 J- T: [) z2 nInstead of the process taking hundreds of thousands of years, it could take just hundreds.
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) l* l6 q4 U1 \7 e8 }2 {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.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。1 x0 L2 [. D- h
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, d% ?! a+ h+ L' M公仔箱論壇Eruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believed
+ X- h9 i, U$ J) iSupervolcanoes are fuelled by giant pools of magma that form deep underground.tvb now,tvbnow,bttvb/ p" ]1 y& f* M
6 w P0 b' @$ z3 P公仔箱論壇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8 L ?& g7 Q; S9 s& e* W/ b
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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.. ?, J+ J7 p% U
+ }! ^1 n4 u6 p; A- p) N9 q& W1 E- Etvb now,tvbnow,bttvbA magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
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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.
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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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X) l' s/ K. z$ Z* kos.tvboxnow.comSteaming Mud Volcano at Yellowstone National Park in winter. Researchers now believe that the supervolcano beneath the park could be more active than thought 2 ~6 v- T- u5 Y& Z7 A& a! s, U
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( [" I1 ~% S0 D9 O% V! Q/ [" q: 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。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。0 {( j9 F* u' [# K( H3 \* k3 x
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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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5 d2 h3 G" l" g% Y: Z9 e& v, mTVBNOW 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。Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.
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+ W; W9 l& h% Etvb 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.
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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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" x" Q( T6 h- ?8 o6 CTVBNOW 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。There is evidence that a similar super-eruption in Indonesia 74,000 years ago came close to wiping out the entire human species.( `2 F- Q" h: k% `3 \* @9 J
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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.
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9 u, _, ~# f0 b" w, s0 mtvb 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.tvb now,tvbnow,bttvb) N1 T6 O" M b( a* U& p
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2 c' p1 P* ?) 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 research is published in the online journal Public Library of Science ONE.
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) ]1 l1 Q( v) [3 U( Itvb now,tvbnow,bttvbLead 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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6 D& k& _, ]3 v$ l, O" T4 UTVBNOW 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 fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.’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。( Q: c% q' h! \$ @$ M) V
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+ u. h. x8 }% B" Jtvb now,tvbnow,bttvbHe 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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