One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic
! q; m2 l E7 K A2 F2 E9 g5.39.217.76eruptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are + g( i" h7 v- H
active each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.
- W3 W x* M5 X: n: a* ]8 Stvb now,tvbnow,bttvbSome volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens,
0 y( g" c/ b0 }. M3 c4 _: ~ y& ^erupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous : |4 k ~ J4 c4 O' G
and explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions. 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% N4 \/ b! s$ X9 ^. M
They tendto be steep-sided cone-shaped volcanoes and often rise strikingly abovethe surrounding landscape.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。! ?- g9 n5 E3 F) H# z5 Q% g6 v7 Q
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。& j ^ D0 N) l* {

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1 K2 g/ `+ p gTVBNOW 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。Many of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above 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。- w% v( o' Z) P B2 V& y- k, Y8 \
of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewas
2 R* T2 J) D' |' N. Ktaken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The ash
1 y# u1 I# A; u1 Q6 [# m1 r5.39.217.76plume reached as high as 50,000 feet.
* w8 `; D6 i8 O. I/ f( A8 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。tvb now,tvbnow,bttvb! V$ r4 V! P# Z1 o2 m
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Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra
y# y9 c9 t p$ R8 }satellite in 2006. Augustine’s dome collapsed in 1883, during its largest historical eruption. It has been erupting for at least 40,000
+ R; n2 [3 {( X' 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。years. The island’s jagged edges were created by massive avalanches.
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Augustine lies in the Cook Inlet at the eastern end of the Aleutian trench which marks the northernmost portion of the Pacific Ring * C' B+ T4 r1 \, ~" t( x$ q* q, f# m
of Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet 5.39.217.769 P& P2 k1 _1 Z
ocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of
7 ]0 y: l4 y3 I8 d$ n9 V* R公仔箱論壇the continental crust, creating magma that drives the volcanic eruptions
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6 m& Y+ Q' H4 ^Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano
% v! U+ h. s) O( |! K7 h2 N7 Cin the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.
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The smooth white cloud, known as a pileus cloud, topping the eruption column may be made of water condensation caused by rising 公仔箱論壇1 q D& J' h( Z% |& a. S
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
3 e- ?. W. ~ C1 Ptvb now,tvbnow,bttvbas a pyroclastic flow.+ u6 c9 C9 h9 q' l
4 r$ y6 @: c" `This photo sparked a debate among scientists about what caused the hole in the clouds above the eruption. Three possible options came up:: A1 }6 p7 c [2 E! _6 [0 z
% U9 O" m: A/ Ztvb now,tvbnow,bttvb * It could have nothing to do with the eruption and simply be caused by the contrast in temperatures between the ocean and the island.公仔箱論壇+ e& Q5 L- ~3 C
* A shockwave from the eruption could have blown a hole in the cloud deck.公仔箱論壇) Z4 v; Q8 \6 p: i) E# l; t) V
* As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.
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& d- S5 `" G" t+ ]7 K( K3 Q# D3 s* _5.39.217.76Alaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet. 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。" e9 G' _# G, |) p( f
It continued erupting on and off for weeks afterward. This image was taken by the commercial satellite GeoEye-1 on March 30 whenTVBNOW 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。) t9 _/ ]* L7 X2 j5 ^
the ash reached heights of 27,000 feet. The volcano’s alert level is still “advisory,” and the aviation color code is yellow.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。5 C0 Z. L8 z: u% c
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Redoubt is a 10,200-foot tall stratovolcano 100 miles southwest of Anchorage in the Aleutian Range, west of the Cook Inlet.
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/ b* G6 v! c. S& q/ d1 S# j9 tMount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes in
$ @6 s4 }, } a公仔箱論壇 the world and is erupting nearly continuously. It is no surprise that there are many great photos of this volcano erupting, including this one
+ B" c. T( R- H- G* N# E; R; Ncaptured by astronauts on the International Space Station in 2002. The lighter colored plumes of smoke on the slope of the volcano in 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。4 X5 v) \7 m1 `2 ]
this picture are from forest fires ignited by lava.
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2 z9 m; [) ^7 x, t% ]# T. PTVBNOW 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。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
0 e' P1 d1 U3 VTVBNOW 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.公仔箱論壇6 t/ }- _" e6 {; ?0 ]& ` X3 L
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& m. ]; R- p# e
% r6 |0 n4 _' ?0 u7 ] N6 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。A NASA astronaut spotted this eruption of Cleveland Volcano from the International Space Station in 2006. The volcano is 5,700 feet high tvb now,tvbnow,bttvb, C5 k0 _/ H. h& e& q1 R
and 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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' l; l- g* s* wtvb now,tvbnow,bttvbPopoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City.
. |5 c" ?- f9 ?* L8 ZThe 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 & y$ ?0 \' \( N/ E- h
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
. o8 e6 R9 g' |/ ]; ` p' f& S0 I5.39.217.76of frequent activity. The plume reached heights of around 30,000 feet.公仔箱論壇0 J. |9 p6 P/ T4 m1 O
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- F6 E% r- U* o' f5 t8 a. m" Q/ k5.39.217.76This eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the
$ Y) l0 n1 H" V0 g$ _; K1 o/ twest coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.
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Chaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic
* U+ E# r J) v3 L0 B* Oflows 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.
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. ]+ ~6 w% o3 [. H+ EThis 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& X& _& ?. `' [$ U( E
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 6 P7 h( ~8 t. w3 z+ G4 T( h0 @9 `
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
% q) @ r: G/ T) P, u8 T- x- z v2 lstationary hot spot, volcanoes are formed. The Hawaiian Islands were formed — and continue forming — the same way.
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+ q% d- I$ w; `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。; h) y5 ]3 \/ y, x5 t5 o
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. 1 W) V3 ~+ P" E) K+ P" w( e+ X& R
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 5.39.217.76' I/ Y' R$ i9 A, z9 d
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, / i K, |: r9 v+ {' `- I1 P
causing avalanches of debris into the crater. |