Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now& O* Q) _. i% B$ B
- 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.
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! `7 O8 ^5 z/ Etvb now,tvbnow,bttvbInstead of the process taking hundreds of thousands of years, it could take just hundreds.tvb now,tvbnow,bttvb% ]9 V) P. K6 w8 F* C6 L# k# j
" W7 S+ R* }5 s7 a公仔箱論壇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.公仔箱論壇/ r1 p$ Z- `3 X4 I/ h
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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
9 b9 F4 n/ |* s8 K4 mtvb now,tvbnow,bttvbSupervolcanoes 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.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。$ F$ D: W6 N5 H/ V
' L. T2 m: z1 u: j+ v5.39.217.76But 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/ G& V/ ^/ ]# U* A6 K2 N1 E, Z
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。$ U: P1 R5 L. \: `: p+ B
A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.公仔箱論壇& w6 |$ ^$ N9 _8 p% ?
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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.5.39.217.76/ q. }; h8 e0 O% Z. H) ?* A! v: b
9 Y2 l( [3 q( E3 u& Ytvb 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.
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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
. I' |# T3 ?6 u0 \) Z6 [2 ~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。! G6 V6 B$ [/ K4 \+ \6 h3 ^/ D
% X' |9 r# k% j- WThe 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
4 c, ^# X( i/ ^# @. l, stvb now,tvbnow,bttvb9 u% t3 C# H! g( |7 f7 W$ {
5 r% D" w" E' e9 Y! @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。Castle Geyser and sunrise Yellowstone National Park Wyoming: Researchers now believe that the huge 'supervolcano' beneath the park is far more active than previously thought5.39.217.767 `8 q f! u5 Q! ^4 @4 \
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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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3 q4 x( Z. E- `. ?: k公仔箱論壇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.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。6 P. _8 `9 F% ?
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' A% L, _7 a" A/ [% M, t7 V1 ?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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0 t2 I& D9 ]6 Z) ttvb now,tvbnow,bttvbThere is evidence that a similar super-eruption in Indonesia 74,000 years ago came close to wiping out the entire human species.
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The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.- w: n1 U, u) v; {( X
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7 x( q1 x( O# c/ e* WTVBNOW 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。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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, F1 @6 I/ _) Z$ m0 [7 X: gtvb 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.
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% t- |$ J/ w8 @8 m9 ptvb now,tvbnow,bttvbThe research is published in the online journal Public Library of Science ONE.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。6 R: e: O" _( }+ C1 K
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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.$ K4 y( t9 y) e8 D: q$ R2 q
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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.’
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0 H4 }: K) V# z7 I2 _, gtvb 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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