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標題: [美洲] 超級火山正待爆發 [打印本頁]

作者: vandas    時間: 2012-6-1 01:50 AM     標題: 超級火山正待爆發

Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right nowtvb now,tvbnow,bttvb( I. U: k2 C+ {6 X

/ T/ m: i: D3 }' S% V4 WA '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. 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。$ j1 y. U2 j2 M

0 ~# f3 x3 v$ o9 s+ X公仔箱論壇Instead of the process taking hundreds of thousands of years, it could take just hundreds.5.39.217.76+ B; R7 n2 d8 W0 \# p" \' q/ L
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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
8 K7 H+ A" f; [) ~. }5.39.217.76Supervolcanoes are fuelled by giant pools of magma that form deep underground.
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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。0 x: u( Z; s; N  _$ j# L
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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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.公仔箱論壇- d9 `4 `- _! O4 w0 t) d

; H6 w& E9 r) D' u' 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。A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
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; `; G* G, S6 O" y5.39.217.76The 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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# p9 g2 K5 J* H0 W8 D( oBlobs of magma occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone Caldera.5.39.217.768 {9 O0 ~, X6 q5 V0 e7 C

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. o- J9 U) T' x1 h' s; M: x5.39.217.76Steaming 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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; @5 [0 W' D) a% f/ EThe 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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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.
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; U% G. i8 P8 h- GThe 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.! W/ L3 B$ E: Q  c4 \- V
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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' a% @7 X2 D$ S# x# u, _0 B

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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.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。& Q4 B. p' C( e1 \

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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.
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) ~8 {/ Y8 C8 P- {7 ?The research is published in the online journal Public Library of Science ONE.
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2 r* G( k# y* R5 vLead 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.’公仔箱論壇+ c. n( k, n/ B

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He said regions such as Yellowstone should be monitored regularly to provide advance warning of a catastrophic super-eruption.
作者: cms    時間: 2012-6-1 08:11 PM

如果真的爆发了,是否就是世界末日?????




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