One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic
# H, Z: u0 W G7 a3 }1 T; t# s4 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。eruptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are
: \8 r* M1 e6 g2 y7 l& L" m3 atvb now,tvbnow,bttvbactive each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.4 D8 S3 R- T T5 b
Some volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens, - e, \5 L; N. b4 ?6 k3 e% u7 b
erupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous
+ t: A9 `! h o: p6 D, I) W$ I! oand explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions. 公仔箱論壇8 r3 `- b- b8 a- k
They tendto be steep-sided cone-shaped volcanoes and often rise strikingly abovethe surrounding landscape.
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Many of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above & ^6 U0 y. H" h# I7 i4 }
of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewasos.tvboxnow.com, R1 M9 @4 x# f9 ^/ h+ ~1 u+ |
taken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The ash tvb now,tvbnow,bttvb7 q! B, j7 O3 N. @$ u
plume reached as high as 50,000 feet.
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' c9 K- D6 J" o+ F2 \公仔箱論壇Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra 公仔箱論壇2 F: T2 O6 D! h. C- |! Z
satellite in 2006. Augustine’s dome collapsed in 1883, during its largest historical eruption. It has been erupting for at least 40,000
! p# w4 b% m/ Q+ L) p2 hos.tvboxnow.comyears. The island’s jagged edges were created by massive avalanches.+ A: M1 t9 Z7 C8 M. m# E7 f* R
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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
2 S; v- _# W4 h' b" r' |of Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet
: k1 V4 \4 }3 K$ l7 i$ Btvb now,tvbnow,bttvbocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of
3 q1 R. @8 z$ ]; u5 n- sthe continental crust, creating magma that drives the volcanic eruptionsTVBNOW 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 L: M% e5 C9 z! D- @* E/ D1 a/ A
公仔箱論壇4 o+ T( q n! o9 p' E6 l8 x
公仔箱論壇$ _4 l% l4 z7 m6 b3 x
* A( O4 h1 F9 u+ v6 Z5 R) _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。Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano
8 n# n2 H6 q% Pos.tvboxnow.comin the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.tvb now,tvbnow,bttvb9 T) v$ S% N, l, Y5 x
8 M7 t, |7 t- B6 `3 n" l) ?- ]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- p) {8 i1 L# R! F2 q% i7 y
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 6 U/ F. L8 ^2 B9 N/ \
as a pyroclastic flow.tvb now,tvbnow,bttvb6 T5 U: M$ N; G5 P+ `3 k
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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:公仔箱論壇% Q# y: g0 S- e0 G/ Z
; @7 ^/ H4 O" E. a& v" I9 x! t7 O# y公仔箱論壇 * 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 i5 b& ?/ q! y% _8 A ~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。 * A shockwave from the eruption could have blown a hole in the cloud deck. r* a% t' C/ @9 a5 l8 [: j# o
* As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.
! i- I z3 t( s8 e1 J9 ^os.tvboxnow.com% [( I2 _* F) E; Q0 l

+ d6 h$ v0 b% n' Ptvb now,tvbnow,bttvb
, D* O9 {: \5 n+ G: b# y8 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。Alaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet.
; @% {0 p# h: l) Gos.tvboxnow.comIt continued erupting on and off for weeks afterward. This image was taken by the commercial satellite GeoEye-1 on March 30 when
, d: p/ z! |) v# j. 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。 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。/ V a( r& i% }# 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。1 Q6 B, w' b: q( e
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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Mount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes in l. q6 i: p6 p4 J" g' b
the world and is erupting nearly continuously. It is no surprise that there are many great photos of this volcano erupting, including this one
2 o" G; K8 @8 Z: B u3 g, X) STVBNOW 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。captured by astronauts on the International Space Station in 2002. The lighter colored plumes of smoke on the slope of the volcano in
" c; A' Q: R: U" F1 G1 tthis picture are from forest fires ignited by lava.公仔箱論壇: p7 z$ b0 k: d: p, {- w/ R
" G W$ I( u# \公仔箱論壇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公仔箱論壇& S1 g( M* W" B; J/ v
also be the oldest-known active volcano.
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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
2 A8 }$ s" D8 atvb now,tvbnow,bttvband 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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8 |- `# Z0 M2 y9 j& o1 G2 KPopoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City.
- N8 q: U3 }2 m% B# [ g# N公仔箱論壇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
! f3 X7 x, T; R. ~: V$ @公仔箱論壇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 os.tvboxnow.com8 X/ _, A2 n. [ z- S3 ^
of frequent activity. The plume reached heights of around 30,000 feet.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( g& l: k/ B' r0 b! m1 T$ r [
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4 c+ l) \4 t& J" V公仔箱論壇This eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the
4 w! \3 R E: j; R: J! {os.tvboxnow.comwest coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.os.tvboxnow.com* E6 {' E( v6 P1 f4 |# ~' D- [2 d
" \+ m' @$ Q( {! \$ I+ M7 \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。Chaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic 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) \) q/ m, k v3 R! h7 O8 A' f
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。- V1 v1 ^* I n1 v' _; g+ L8 N1 G
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; f& V, ]5 t, `) t2 j" C0 v( {0 }tvb now,tvbnow,bttvbThis image of the Sierra Negra volcano in the Galapagos Islands was taken by NASA’s Terra satellite in 2006. Sierra Negra
* V% p; {$ |+ ~' c- a6 E, Z% E3 P' [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 公仔箱論壇2 V* _- A z# G
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
5 i; V! g* e/ }+ ?tvb now,tvbnow,bttvbstationary hot spot, volcanoes are formed. The Hawaiian Islands were formed — and continue forming — the same way.tvb now,tvbnow,bttvb! S, k- i) d& C; E9 g; Z
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4 L( a; [7 B. sos.tvboxnow.comNASA’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: q3 j% `4 p3 D: N. o6 F
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
. ]! J4 B% `7 M5 C o6 O5 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。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,
$ B c @: Y0 ` ?' l+ p+ G1 vos.tvboxnow.comcausing avalanches of debris into the crater. |