One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic 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- R* S. d2 J9 w4 w; x
eruptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are
3 t1 [$ v# R, t, s+ z Z. c/ B3 Btvb now,tvbnow,bttvbactive each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.
- ^9 M) {7 R- \- F公仔箱論壇Some volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens,
A! [, L8 W. _5 aerupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous
5 q: [- S* a! G8 S7 a8 s: Eand explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions.
2 R8 M/ S0 R# k, V2 D& z+ {They tendto be steep-sided cone-shaped volcanoes and often rise strikingly abovethe surrounding landscape.
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7 J2 C2 G2 P/ b6 u, I. Awww2.tvboxnow.comMany of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above
$ e: v# t1 y) L) |' 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。of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewas
& i1 `+ l4 {5 v; Utaken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The ash
& F& l) V7 F7 B* r: q8 p5 X jTVBNOW 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。plume reached as high as 50,000 feet.
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# u4 |2 Q# }3 P6 ~Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra $ }* s* w+ {/ R4 k+ s1 T8 M
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。) m) r) T3 c/ f) I1 x
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
- y) _: W: J1 Dwww2.tvboxnow.comof Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet
% _: ]2 ]/ y" P0 }8 @5 S* r公仔箱論壇ocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of
" M+ N: v8 D7 |) v& o+ etvb now,tvbnow,bttvbthe continental crust, creating magma that drives the volcanic eruptions
4 c( \' S" ^1 } TTVBNOW 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。
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# |' ^- ~0 t; a) t0 j3 ~公仔箱論壇
@: @7 o7 a0 u9 A. OTVBNOW 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。Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano tvb now,tvbnow,bttvb1 [" \( d0 k5 y- [- H: Q7 c# F( e
in the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.公仔箱論壇/ h; g, r! P7 J. U$ Y
* c' s4 G1 {( T, _% E( F! K* awww2.tvboxnow.comThe smooth white cloud, known as a pileus cloud, topping the eruption column may be made of water condensation caused by rising
7 H7 @: M" \$ f4 A$ qTVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。and cooling of the air above. In contrast, a dark gray cloud of ash near the ground is probably an avalanche of hot ash and rock known tvb now,tvbnow,bttvb) k3 ~/ Y% D) k
as a pyroclastic flow.
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This photo sparked a debate among scientists about what caused the hole in the clouds above the eruption. Three possible options came up:8 K8 i, a7 v/ s
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* It could have nothing to do with the eruption and simply be caused by the contrast in temperatures between the ocean and the island.
3 ?% j, J3 y; D2 Z. a" L2 Qtvb now,tvbnow,bttvb * A shockwave from the eruption could have blown a hole in the cloud deck.
: W: Y, E* |- O: S- S$ v3 Q * As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.
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+ \) ~0 }& f: ?7 |! W7 N8 \8 d WAlaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet. # V D: T2 Q- H+ p
It continued erupting on and off for weeks afterward. This image was taken by the commercial satellite GeoEye-1 on March 30 when' w& F8 t6 f% {( c; F
the ash reached heights of 27,000 feet. The volcano’s alert level is still “advisory,” and the aviation color code is yellow.
, [- ^- U \* q" X& 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。
" r8 C8 K* G$ m; p/ k/ ^) u6 o3 r. tRedoubt is a 10,200-foot tall stratovolcano 100 miles southwest of Anchorage in the Aleutian Range, west of the Cook Inlet.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 j9 i) w! M5 p
6 s. D0 f$ q7 F, f+ S3 A ^( Utvb now,tvbnow,bttvb
" i2 ?% v" r! i* H6 ?. _6 h8 uwww2.tvboxnow.com
3 k8 i; K! J0 j4 S: H# qTVBNOW 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。Mount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes intvb now,tvbnow,bttvb; k& h4 D5 P1 u1 A2 x w. D* s: B$ L
the world and is erupting nearly continuously. It is no surprise that there are many great photos of this volcano erupting, including this one www2.tvboxnow.com, S: s3 S& c* R. @7 r! s3 S' E6 S
captured by astronauts on the International Space Station in 2002. The lighter colored plumes of smoke on the slope of the volcano in
: o6 W0 r5 g/ R! M* |tvb now,tvbnow,bttvbthis picture are from forest fires ignited by lava.tvb now,tvbnow,bttvb6 p2 a* Y3 i q: `$ T+ D
$ d* g d$ T% \1 N U" V3 U( |7 [+ nEtna 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( m" v: `+ U) ?' F- ZTVBNOW 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.
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% _ z2 P- W: ?, M9 `' K1 X7 K公仔箱論壇A NASA astronaut spotted this eruption of Cleveland Volcano from the International Space Station in 2006. The volcano is 5,700 feet high
~+ W# H$ r' r. }+ ywww2.tvboxnow.comand 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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5 J+ ], X( g0 |1 V/ ITVBNOW 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。
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; b( y8 E+ L. B+ C0 s2 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。Popoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City.
% B* K( d* s" g. e. t9 R0 e4 Q$ kThe 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 公仔箱論壇% b5 s6 }: m' H" H4 t$ @9 ^: S
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 www2.tvboxnow.com4 I, `; T+ @! U4 I. S* m8 s- s6 q
of frequent activity. The plume reached heights of around 30,000 feet.
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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 @/ E) J$ m+ J E4 |( w1 h6 g
This eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the www2.tvboxnow.com" y: x. [1 @, n- D/ L- I. ?4 T
west coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.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 g1 K* ?- [- L" {5 l! m/ l7 x
0 V5 @3 [+ n* ]8 M1 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。Chaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic
5 v) a: `9 v1 u/ U9 U c) sflows 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.tvb now,tvbnow,bttvb) s0 L- U- @4 ?0 X. o) b
www2.tvboxnow.com. k; V ~- F+ j8 T! L3 i
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* _ U# \6 ]5 {# C0 n7 I mTVBNOW 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
3 m) S4 C3 ^+ G. ~9 G2 }7 Vwww2.tvboxnow.comis 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
e8 e. D. m" R- ]# N% fformed 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
$ e/ u, P$ }! c9 Nstationary hot spot, volcanoes are formed. The Hawaiian Islands were formed — and continue forming — the same way.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。, O7 e! ]( k2 A, S' {
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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. 公仔箱論壇% a o( W3 p, `" v5 \
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
4 p% o- K2 F/ F公仔箱論壇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, ) N) z8 R, D6 y
causing avalanches of debris into the crater. |