One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic tvb now,tvbnow,bttvb A, V; ]' F2 j& j1 ?
eruptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are 5.39.217.76. T: s2 ]0 p8 R- u0 t
active each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.
5 _1 m8 J' {( ~& F# ^Some volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens,
0 U1 x! }3 O% Z5 e! D q! E% |erupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous * J# j/ w& p# s2 F8 z, {
and explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions.
; b2 { \* S& x( {6 {& J公仔箱論壇They tendto be steep-sided cone-shaped volcanoes and often rise strikingly abovethe surrounding landscape.( d: r! ]) V; J: _& `, R! @4 c# M
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) D9 ^# S& E4 l( E2 f! E" yMany of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above tvb now,tvbnow,bttvb0 d2 J6 t0 x( I$ z! I
of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewas5.39.217.76, K. H) R8 y. r/ e& v8 a& A
taken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The 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。+ `; {0 i2 n0 B7 J. t
plume reached as high as 50,000 feet.
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Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra
2 U0 j7 `) z- b0 |* N公仔箱論壇satellite in 2006. Augustine’s dome collapsed in 1883, during its largest historical eruption. It has been erupting for at least 40,000 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。3 s. Y: U g, v
years. The island’s jagged edges were created by massive avalanches.8 b1 [1 _( |. U+ O8 c
1 v L: r6 }0 v5 vAugustine lies in the Cook Inlet at the eastern end of the Aleutian trench which marks the northernmost portion of the Pacific Ring
$ f: h8 q4 J4 i6 Z: O5.39.217.76of Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet
& o6 U6 u M) g8 j5.39.217.76ocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of
( A+ f& p9 s& }8 a7 a% s5.39.217.76the continental crust, creating magma that drives the volcanic eruptions
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Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano tvb now,tvbnow,bttvb: x/ P: j7 I. Z# r
in the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.) u6 P4 |2 J- |5 }. b$ N0 Q4 L: p
) p& W7 W* ^! C1 b" Ctvb now,tvbnow,bttvbThe smooth white cloud, known as a pileus cloud, topping the eruption column may be made of water condensation caused by rising
5 y+ Y2 q3 f# N+ c3 b% @7 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。and cooling of the air above. In contrast, a dark gray cloud of ash near the ground is probably an avalanche of hot ash and rock known
% L4 D( r" D0 _' P3 h' uas a pyroclastic flow.
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" `$ e- S3 v( L2 S2 b# p$ ~% `5.39.217.76This photo sparked a debate among scientists about what caused the hole in the clouds above the eruption. Three possible options came up: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。+ c/ V3 `& l$ k% }8 ?# M
$ i5 @4 d$ L5 {/ J+ T9 {, \$ h6 S# e * It could have nothing to do with the eruption and simply be caused by the contrast in temperatures between the ocean and the island.
2 F2 U7 i0 K7 J/ ]0 d公仔箱論壇 * A shockwave from the eruption could have blown a hole in the cloud deck.
6 m: w, y- F- {# N, O S * As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.5.39.217.76+ Z3 n) l) M x8 x! }7 T6 b
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。' R: |1 [7 ?9 ?6 K
 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。- _/ i' q! G- L
, f# g% ^9 N3 V y/ M- s" _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。Alaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet.
! I7 z5 s: L3 Z7 n3 J/ u公仔箱論壇It continued erupting on and off for weeks afterward. This image was taken by the commercial satellite GeoEye-1 on March 30 when
- ~. b1 W0 l# ~( z. E8 `) ^. L, { the ash reached heights of 27,000 feet. The volcano’s alert level is still “advisory,” and the aviation color code is yellow.tvb now,tvbnow,bttvb! w: s5 e: B5 @ J5 E2 K3 U+ B5 S
/ o, Y7 n6 K( K1 V# D; a# [5.39.217.76Redoubt is a 10,200-foot tall stratovolcano 100 miles southwest of Anchorage in the Aleutian Range, west of the Cook Inlet.9 V# I& b: e0 p* j8 i5 f* G
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Mount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes in公仔箱論壇8 t: N7 {8 G7 B! M
the world and is erupting nearly continuously. It is no surprise that there are many great photos of this volcano erupting, including this one 6 N: p( L' S+ r4 Y1 A9 d; a. w9 A+ S
captured by astronauts on the International Space Station in 2002. The lighter colored plumes of smoke on the slope of the volcano in
3 h* W4 g4 s' [4 t# [% jthis picture are from forest fires ignited by lava.5.39.217.76/ ~" o0 Y. A# s* u9 | M" Q- w5 I
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。. Z* ?& o2 W/ _3 A/ f- f5 M
Etna is a stratovolcano located on the island of Sicily. It is one of the most studied volcanoes in the world and. at 500,000 years old, it may
G% e/ S" R* y y" 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。also be the oldest-known active volcano.
+ W+ E! A. q3 C4 A% r; Z# U; Utvb 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。6 G$ G5 P& m. k, g+ p3 [) H5 C C
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A NASA astronaut spotted this eruption of Cleveland Volcano from the International Space Station in 2006. The volcano is 5,700 feet high
4 c0 G. \; D, T. mand claimed the only known eruption-related death in Alaska’s Aleutian Islands in 1944. Its symmetrical, cone shape is typical of stratovolcanoes.
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& \% I/ E8 Y8 G5.39.217.76Popoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City. 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。 t$ N3 S7 l+ G0 C. `1 Z
The second highest peak in Mexico at 17,800 feet, this glacier-covered stratovolcano has erupted at least 20 times in the last 500 years and has caused 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 ?% v ^6 U1 G& b% A4 e4 [
multiple evacuations of the city. This eruption in 2001 was caught by astronauts on the International Space Station, near the end of a seven-year period 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。9 K1 z1 t; Q# Z; L: G
of frequent activity. The plume reached heights of around 30,000 feet.公仔箱論壇* ]8 s) \1 }$ }5 ?) H
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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。* L# g3 e1 l2 y1 G; D; q# S3 @
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) ~% X. I) E# k- y! KTVBNOW 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。This eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the
2 B" i0 p3 G, M/ x8 \* p/ 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。west coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.
2 W: P; g6 b8 j9 r# ~5.39.217.76TVBNOW 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。8 K2 g9 w ? c/ D
Chaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic
9 w! K v0 B4 [flows and volcanic mudflows called lahars. The caldera is relatively small at less than two miles wide, and sits on the flank of the larger Michinmahuida volcano.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。8 u3 p4 Y% G* X j; f
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 公仔箱論壇! N7 q4 k+ x. U' n8 v
1 w, c* J" Q* N8 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。This image of the Sierra Negra volcano in the Galapagos Islands was taken by NASA’s Terra satellite in 2006. Sierra Negra 5.39.217.76' `7 l$ B4 h4 J! Z- N, `+ ]; {
is a shield volcano, which are made mostly of previous lava flows and tend to be broad and gently sloping. The Galapagos are part of an island chain
j+ V+ h1 k! ]0 z4 p6 f, @formed by a hot spot where a plume of hot mantle rises up and melts the base of the ocean crust. As the Pacific plate moves over the relatively ' `: x1 b$ h/ S' G) b5 S
stationary hot spot, volcanoes are formed. The Hawaiian Islands were formed — and continue forming — the same way.+ M m5 W, Y) \9 a- r
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1 `+ I: B! N5 r" o* Z% I" [NASA’s Terra satellite snapped this image of Shiveluch volcano erupting on Russia’s Kamchatka peninsula at the edge of the Pacific Ring of Fire in 2004. 4 I9 x$ x1 l/ E& ]# I5 O
A lava dome had been growing in the volcano’s crater, followed by intermittent eruptions that lasted weeks. Shiveluch is a 10,400-foot-high stratovolcano / q& h a' }3 F( h- }2 F
that is at least 60,000 years old and has been erupting fairly often for the past 10 years. Its dome has collapsed multiple times, most recently in 1964,
, Z0 q) b0 p* H4 O, I- 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。causing avalanches of debris into the crater. |
發表於 2009-12-22 08:34 AM
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