Supervolcanoes with power to 'destroy civilisation' explode far more rapidly than scientists had believed - and one could be bubbling under U.S. right now
5 A5 W: B# ?6 u2 o: h+ L7 B) |公仔箱論壇- 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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Instead of the process taking hundreds of thousands of years, it could take just hundreds.
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8 N' _; q4 k5 q- ?7 H2 e: d7 TThe 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
0 S+ d; O! a1 ]+ O& V, l5.39.217.76Supervolcanoes are fuelled by giant pools of magma that form deep underground.tvb now,tvbnow,bttvb% S) H/ C5 _: x
* z1 }! K3 e! H N% m0 JGeologists 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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4 O% `+ [* j; S" P. X4 \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$ d6 G) A, T! `2 ^8 S
0 ~) `0 m% n0 ?5 }- H4 @* jtvb now,tvbnow,bttvbA magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.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。! C4 Z2 o9 N& @$ F% m: f
6 d9 k) \+ [" b, LTVBNOW 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 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.tvb now,tvbnow,bttvb# o; `4 r& b* ~- [ m+ u& j* d
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, |0 ^1 Z/ j# h8 qtvb now,tvbnow,bttvbSteaming 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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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( F$ I- ^4 n8 L4 }* L) h k
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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.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。, h; Y( {- ?. M; J0 P2 Y2 B
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7 ~# E4 b% v7 o% aThe 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.tvb now,tvbnow,bttvb( s/ T' f/ k# g( o) _& P
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% B1 A/ F2 b. ?3 l: h. G5.39.217.76There 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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* O! q9 i5 |5 I& |公仔箱論壇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.- p) t; k4 ~$ \ c( N- L
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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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The research is published in the online journal Public Library of Science ONE.) ]$ Z- y. r: t2 o# j
$ t4 l# s3 y9 U DTVBNOW 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- [& N3 s. Z% ETVBNOW 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.' o0 p2 y7 |8 K
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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' f( c2 _# ]/ v8 l+ ]
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% R6 X/ Q8 L: y |# Q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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