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 q/ Y @6 S. |' F! aTVBNOW 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.
9 ?# B6 R* d4 H- w' ^. M6 B8 XTVBNOW 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 '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. 5.39.217.76$ ^$ t) f! K8 A; j0 j
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Instead of the process taking hundreds of thousands of years, it could take just hundreds.
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_1 w3 x/ O, p+ s: q( C5 w5.39.217.76The 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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; r4 G" Y& j: M& s) V' c' }tvb now,tvbnow,bttvb 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。/ [ @" R2 o! N5 H& u* ~
Eruption: Supervolcanoes with the power to destroy human civilisations may build up a deadly head of steam far faster than scientists believedtvb now,tvbnow,bttvb- a a1 D" ]% a' d0 s7 L& q
Supervolcanoes are fuelled by giant pools of magma that form deep underground.
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: K' }) P( \# D9 e" _7 n1 hGeologists had thought it took between 100,000 to 200,000 years for a supervolcano magma pool to build up enough pressure to erupt.( f! {( [- w0 p4 v& _/ N9 Z U: o
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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.5.39.217.769 x, Z u3 ^9 A" y
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A 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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, {: y' i+ k# K+ d" l- j6 s; Itvb 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.tvb now,tvbnow,bttvb9 w9 u: U* j* Z- G e
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* I7 ]% C, n2 L# R0 C& U/ u1 D" ^公仔箱論壇Steaming Mud Volcano at Yellowstone National Park in winter. Researchers now believe that the supervolcano beneath the park could be more active than thought
' E& J. Z* g) y+ V/ _tvb now,tvbnow,bttvbTVBNOW 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。& t' V4 t2 G$ L [5 |6 w
$ M' h8 s% w9 a4 t# a Y& Q( ]5.39.217.76The 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; g3 K/ ~! w! x0 a) 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公仔箱論壇( Y3 f6 A( ~1 d% }7 {
; X- m. [1 S8 d3 H/ 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。Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.
) R; e4 L9 A2 y" ?2 j' y( _9 ^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。
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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.1 [7 A7 G+ R! b3 }, b
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/ L) t k3 |, P w* rTVBNOW 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 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.5.39.217.76: Q3 ~, R( L; }0 ?) Q3 O, ~
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The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.tvb now,tvbnow,bttvb# y) d3 b- H! J: x0 K& Q! v
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7 L* l8 L0 R8 s* ?tvb 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.
7 N4 L1 l7 ^# z$ } J* `" XTVBNOW 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。; B+ }3 ?2 w+ O" Z
1 e% h6 p$ J& L7 N4 l# 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。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.
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The research is published in the online journal Public Library of Science ONE.
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5 i: H& |7 W7 {( m公仔箱論壇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。' D- N1 e+ [( V7 l S9 f
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.( w- x( G1 v: L! F$ c0 E" s- v* x
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' @5 A& S1 N1 U: M9 @2 d‘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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1 ^8 P/ Q* _' U5.39.217.76He 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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