One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic
8 V5 d" m& b6 }tvb now,tvbnow,bttvberuptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are
2 T/ V: `9 l& w! q3 H3 x" 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。active each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.
' B3 j- ^; M% U* M+ W$ @: j. 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。Some volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens,
O0 }- i- i- z* K! c$ x, f! verupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous
6 O: E# W* e3 b4 k- I) m公仔箱論壇and explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions.
# e- D5 k$ a" q% t7 K# ^* g4 O7 ]tvb now,tvbnow,bttvbThey tendto be steep-sided cone-shaped volcanoes and often rise strikingly abovethe surrounding landscape./ _' p) ?- M* S! E' p
0 h& K; U1 b9 A- u T& htvb now,tvbnow,bttvb
4 G+ b _5 R+ r公仔箱論壇
) Z/ x! ]1 U! F( gMany of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above # X$ `& b( N# I+ C9 H b
of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewastvboxnow.com: z# u$ m9 f/ B4 h
taken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The ash tvboxnow.com3 G* X! L& t9 w$ i/ h" d; l, R" c6 h5 k
plume reached as high as 50,000 feet.tvboxnow.com( Y Z2 A/ {9 y% ?+ ^. T
tvb now,tvbnow,bttvb8 W* _! y g6 y* _: Q

$ {6 A4 W% E1 C1 U0 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。tvb now,tvbnow,bttvb/ A6 |/ |) C. B7 I) Y0 H4 \
Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra
- Q( e0 `& z( u5 t: C+ `& }* N+ 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。satellite in 2006. Augustine’s dome collapsed in 1883, during its largest historical eruption. It has been erupting for at least 40,000 tvb now,tvbnow,bttvb# M& V% O$ Y/ I8 [' p
years. The island’s jagged edges were created by massive avalanches.
4 V8 M4 Z/ M/ V. {3 K; x% b 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。tvboxnow.com7 j2 O. ^( [2 @
Augustine lies in the Cook Inlet at the eastern end of the Aleutian trench which marks the northernmost portion of the Pacific Ring : F( ?$ Y, @1 R1 X {
of Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet 公仔箱論壇2 v. t* R/ L2 _/ \" h
ocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of
. p+ V9 H4 R$ \$ Ttvb now,tvbnow,bttvbthe continental crust, creating magma that drives the volcanic eruptions. u' }+ c. L) x- ]' p
1 g7 G- `2 O$ H% `2 x i! NTVBNOW 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。
, Y: P. [ [0 e7 k- G" r" R5 U8 c8 Q u' l
Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano
& \( U d( g9 p. N: l' xin the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.- i ]4 N+ Q3 g2 F; k9 J
' R* ^! M% {/ X, b0 ]: k0 BTVBNOW 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 smooth white cloud, known as a pileus cloud, topping the eruption column may be made of water condensation caused by rising tvboxnow.com4 { s6 B& x4 v9 g& l
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
$ d/ i: n0 ~' n7 h% }4 F公仔箱論壇as a pyroclastic flow.公仔箱論壇' S* J# E) F6 W0 W
4 ?; P: t. A x( Gtvb now,tvbnow,bttvbThis 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7 G6 |* n5 x! D
' `# \, s0 i6 \4 @1 d& ]* ]! M
* It could have nothing to do with the eruption and simply be caused by the contrast in temperatures between the ocean and the island.
6 b8 i+ p1 ]. t* l' M4 H& Y6 d公仔箱論壇 * A shockwave from the eruption could have blown a hole in the cloud deck.* W& o% `# o) X% S2 x* A) k& n
* As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.公仔箱論壇+ O4 P8 c. {: \# u+ ]' b: n
( a( H, }. |' _# k( b" gtvboxnow.com - p; r6 `! q5 H/ v* b8 ]* O1 m
tvb now,tvbnow,bttvb4 I1 W2 \ A( d8 R* o. c
Alaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet.
, o- p& U( k' v* @tvb now,tvbnow,bttvbIt 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。7 p' p$ w- `/ v% {6 H& _: c
the ash reached heights of 27,000 feet. The volcano’s alert level is still “advisory,” and the aviation color code is yellow.4 M/ b2 N% j T* |* |$ H
- [5 v5 n6 T J6 L6 dtvboxnow.comRedoubt is a 10,200-foot tall stratovolcano 100 miles southwest of Anchorage in the Aleutian Range, west of the Cook Inlet.9 M% e5 r/ N9 W3 { i
: x! f- ]- F8 \. Q% B, m3 Atvboxnow.com
1 E6 c8 l4 @/ n) A
! m1 [$ L5 J# R' g8 y3 G3 t7 w9 wMount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes in
3 ]) q5 G- s$ l, t" i/ W7 f 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 L) L$ d9 b. Q8 l, {! Zcaptured 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。1 x" e2 F `, J' {' E
this picture are from forest fires ignited by lava.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。. D) R1 X! c$ e$ Q+ c3 j* G
* T2 N, z9 d* m5 y6 E6 cEtna 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
% D2 T* M$ ]8 X& s7 l# ttvb now,tvbnow,bttvbalso be the oldest-known active volcano.
1 m' @* p, G* w' J1 k9 W
# q: d* o5 M8 l- t
! V+ y8 r% Y' b7 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。
6 i$ d# d3 g; s% _# n$ n2 {A NASA astronaut spotted this eruption of Cleveland Volcano from the International Space Station in 2006. The volcano is 5,700 feet high tvboxnow.com2 L! c N; Z/ p8 S) g# w
and claimed the only known eruption-related death in Alaska’s Aleutian Islands in 1944. Its symmetrical, cone shape is typical of stratovolcanoes.$ x# u1 X5 k0 j
tvb now,tvbnow,bttvb o5 s. b# f9 t. S. o

/ q! B T$ 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。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 t! F) f! f! P/ G Y
Popoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City.
* y+ C* A4 p4 ?" S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
4 S% t* C6 ]% `( I, r: M) p' Q# q2 btvb now,tvbnow,bttvbmultiple 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
% |# {6 i! z7 q c0 B3 l$ Z) hof frequent activity. The plume reached heights of around 30,000 feet.tvboxnow.com7 ]# s2 `4 {) L- {/ B5 @
4 O: t8 L8 o% ]: |( P, L# `& g 公仔箱論壇9 |+ Z1 y) n; g
8 ^. ?8 y+ b' A! v( r# P/ e* V$ }
tvboxnow.com& ~9 R% P1 M5 E
( ^4 C L1 L9 U( f; Ktvboxnow.comThis eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the 7 c6 {# W& b( g. Q& C0 K* G
west coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.# w0 B/ J' x+ [6 ?8 t5 U# ]# }' W' Z
( ~0 C. B9 V. R6 OChaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic
! a& g* D/ ]7 X6 D1 g- ]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.
" a8 [+ j" ] f; ?7 x9 e6 J6 N1 W# @6 ^; q& ~

9 ?8 T- O8 q; Ctvb now,tvbnow,bttvb9 Z3 L$ L# f X0 {3 C- ^1 z, w% K( e0 O
This image of the Sierra Negra volcano in the Galapagos Islands was taken by NASA’s Terra satellite in 2006. Sierra Negra 5 m) I' T2 V; n9 _, [: V
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: P5 K* |$ K" I
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 公仔箱論壇; B" k# j+ T" Q8 H. Y2 X) w
stationary 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。7 @8 h H% R+ p7 E/ @
1 m1 f# c- Y* F# f O* `& \% @4 g
tvboxnow.com. F( S! y$ ?8 o5 ^8 v' Z9 p
( T" P' o, m7 C s$ V
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 ^: | W8 P, i9 P. 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。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
$ O; h0 }4 P) X& l" R; Gtvb now,tvbnow,bttvbthat 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* H# D( J' Q' ~tvboxnow.comcausing avalanches of debris into the crater. |