One of the most violent but beautiful reminders that we live on ageologically restless planet are volcanic
; b: A9 ~1 Y* P5.39.217.76eruptions. Around 550volcanoes have erupted at least once in historic times, and around 50or 60 are tvb now,tvbnow,bttvb) v+ M X# C, M1 w' S0 H
active each year. On any given day, as many as 10 volcanoesmay be spewing ash or lava somewhere on Earth.
. B+ N$ Y' g, mSome volcanoes, such as Mount Etna in Italy, erupt almost constantlyfor years on end. Others, like Mount St. Helens, tvb now,tvbnow,bttvb7 o3 A7 V; Y: q- w
erupt rarely andsometimes extremely destructively. Like Etna and Mount St. Helens, manyof the most dangerous ! [( M1 `" c- K6 f- ~
and explosive erupters are stratovolcanoes, whichare made of layers of ash and lava from previous eruptions. 5.39.217.76* o& W1 L U; G. E) h
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。6 H9 U4 _6 z! [2 h4 p, h8 p$ c) e
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。" F/ A4 z- R' P0 N
6 u! q9 Q) f7 _6 f" ?
5.39.217.76& W7 Y8 s7 o; B0 k" t, i& n
Many of the stunning images of eruptions captured from space are ofviolent stratovolcanoes, such as the one above 公仔箱論壇$ X$ I+ Y3 ]4 M3 B" M2 p& d
of Kliuchevskoi, themost active volcano on Russia’s Kamchatka peninsula. The image abovewas
; H8 c) a$ c, _( S5 C( X公仔箱論壇taken by astronauts on the space shuttle Endeavour in 1994, as an eruption was just getting underway. The ash
. C, P: k, v% o2 [! @0 D6 \plume reached as high as 50,000 feet.
% ]8 `! Q0 r8 ^. ?$ o: A7 G$ j, 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。$ I3 s, z: u2 I* a+ s+ i; o" T' f
2 T3 N: G- r3 d! z) c, w4 b+ N
7 A/ `9 R/ L# H6 ]4 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。Augustine Volcano is a 4,100-foot-tall, 7-mile-wide stratovolcano. This eruption was captured by NASA’s Terra " [5 K( W% @! O7 W5 {
satellite in 2006. Augustine’s dome collapsed in 1883, during its largest historical eruption. It has been erupting for at least 40,000 ( `' {7 V0 e+ K- @( `% l
years. The island’s jagged edges were created by massive avalanches.2 {" J e+ `6 L8 a4 ?1 J9 T% G- r! a
# ?2 M8 Y5 t: O- Ztvb now,tvbnow,bttvbAugustine lies in the Cook Inlet at the eastern end of the Aleutian trench which marks the northernmost portion of the Pacific Ring
- n( ?; F. r4 Z Utvb now,tvbnow,bttvbof Fire. Volcanic activity here is caused by the subduction of the Pacific plate beneath the North American plate. As the wet
5 W* U0 b* K4 HTVBNOW 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。ocean crust descends into the molten mantle below, superheated water is squeezed out and rises up to melt the bottom of 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。! N" C: ]1 d% I. q4 j4 u
the continental crust, creating magma that drives the volcanic eruptions
. ]$ s* R4 f; }$ n( }) |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* y0 D) S! m# V1 @
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 u- O1 V, O: X
公仔箱論壇 f# N# \8 s: A/ O5 H
Astronauts aboard the International Space Station caught a lucky glimpse of the start of this eruption of Sarychev Volcano ' H& i2 B4 P; E2 L& |
in the Kuril Islands, northeast of Japan, on June 12, 2009. This was the volcano’s first eruption in 30 years.
4 `5 Y( p- [) _7 |! f- J5.39.217.76tvb now,tvbnow,bttvb7 {) U% Q! U5 V3 \
The smooth white cloud, known as a pileus cloud, topping the eruption column may be made of water condensation caused by rising 7 S ?; L' a, X1 |0 }9 `
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 / j) |- s5 i* a
as a pyroclastic flow.
0 s3 Y: q7 O G+ Y+ Itvb now,tvbnow,bttvb5.39.217.76- @5 [! n1 u. K* ~' @% T
This photo sparked a debate among scientists about what caused the hole in the clouds above the eruption. Three possible options came up:
# U3 G5 H. [# V k$ p) }5.39.217.76
( ]' |( b9 D) U8 j4 _/ Z. f * It could have nothing to do with the eruption and simply be caused by the contrast in temperatures between the ocean and the island.
+ _4 g9 w4 q# Z- V ]5.39.217.76 * A shockwave from the eruption could have blown a hole in the cloud deck.tvb now,tvbnow,bttvb: u% @' T/ f6 L+ p- f! t( L9 U
* As the plume rose, air flowed downward along the sides and became warmer and evaporated the clouds.
+ i+ B9 L8 @6 L8 u& ]3 W5.39.217.76
5 f' D1 D3 Z% R" T7 G) x ! d& i; t' Y1 x$ U
1 k/ [6 B `. B6 HAlaska’s Redoubt Volcano erupted five times in one night this year after almost three decades of relative quiet. 公仔箱論壇; u* K6 C# V, d
It continued erupting on and off for weeks afterward. This image was taken by the commercial satellite GeoEye-1 on March 30 when
! v2 G; X j- P$ I, x! b& l the ash reached heights of 27,000 feet. The volcano’s alert level is still “advisory,” and the aviation color code is yellow.
( q- ^2 N5 V$ _! h2 R; X0 P
' N* {. d3 R; B4 zRedoubt is a 10,200-foot tall stratovolcano 100 miles southwest of Anchorage in the Aleutian Range, west of the Cook Inlet.公仔箱論壇3 ~/ m7 |! m( e, a! B
* ^$ I8 x3 P" m# ?, k3 b公仔箱論壇
% W4 f( o& o2 V$ C公仔箱論壇0 l4 X) F5 E/ z7 C% y: J
Mount Etna is the second tallest volcano in Europe, at almost 11,000 feet. It is one of the most active volcanoes in
- b8 r% K4 v3 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。 the world and is erupting nearly continuously. It is no surprise that there are many great photos of this volcano erupting, including this one 公仔箱論壇6 `" ~" R, h9 S3 H$ A& ~8 Y/ W
captured by astronauts on the International Space Station in 2002. The lighter colored plumes of smoke on the slope of the volcano in
2 o! s7 H8 o" {8 v, D% a- }this picture are from forest fires ignited by lava.tvb now,tvbnow,bttvb j/ m( E# G' S; J$ e W0 x1 U- d
5.39.217.76; q6 ~* V- G$ |& t% @
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
. U* y' y; E" l, J& N/ s公仔箱論壇also be the oldest-known active volcano.5.39.217.76- U( t# P4 ?6 `
% W! O9 w2 h$ H5.39.217.76 tvb now,tvbnow,bttvb; i6 _2 R) N3 O% Z H& s( N' W3 X! `
公仔箱論壇; U+ ?. |& Y- k
A NASA astronaut spotted this eruption of Cleveland Volcano from the International Space Station in 2006. The volcano is 5,700 feet high
: {" h5 k% }$ ~and claimed the only known eruption-related death in Alaska’s Aleutian Islands in 1944. Its symmetrical, cone shape is typical of stratovolcanoes.
/ [: |$ w$ O2 |0 K7 j2 U. A
. L' |2 }$ p+ }- H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。( J: a3 L' d* \. z2 r5 E
9 H! ^0 P$ @' ?& q! K5 s& f
Popoépetcatl, which means “smoking mountain” in the Aztec language, is a very active volcano just 44 miles outside Mexico City. + y9 S# a3 w6 p9 b
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
2 M/ s2 A: k. W# u3 Q& H4 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。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
+ |7 m2 o2 Z @) i: r, v0 }9 w, f9 |; mtvb now,tvbnow,bttvbof frequent activity. The plume reached heights of around 30,000 feet.
# E. J4 J4 o$ z% X- }5.39.217.765.39.217.76" q9 i# |4 m1 t0 c! Q
tvb now,tvbnow,bttvb% A, b. C. _& u* I l
tvb now,tvbnow,bttvb& g& d: u/ c+ S" a6 z* ?
tvb now,tvbnow,bttvb9 G+ y1 X+ b7 ?& e2 W' Z4 _6 c1 t1 k0 H
公仔箱論壇# p, E6 K# n1 {9 C$ |
This eruption of Chaitén caldera in Chile was photographed from the International Space Station in May 2008. Volcanism along the
( C9 v0 B% n" w+ v公仔箱論壇west coast of South America is the result of subduction of the oceanic Nazca plate beneath the South American plate.
( Q; G& p4 M- n' k5.39.217.765.39.217.76* V% ?3 @/ j* D. p2 v7 W* y
Chaitén was last active more than 9,000 years ago. The violent 2008 eruption inundated the small coastal town of Chaitén with ash, pyroclastic 5.39.217.767 Q# d& q0 ^$ {
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.5.39.217.76: K* _/ i6 w/ f! p
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。! n Z2 S: ?' G0 t" O
5 c4 d0 |4 p. l1 v" Y$ N3 S% E
& M; g& m/ v3 ?4 mtvb now,tvbnow,bttvbThis image of the Sierra Negra volcano in the Galapagos Islands was taken by NASA’s Terra satellite in 2006. Sierra Negra 4 N6 V2 z* V3 {3 \
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 5.39.217.76/ |. j4 q) f7 a ?" _
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 tvb now,tvbnow,bttvb4 \! C7 _/ [* d1 F
stationary hot spot, volcanoes are formed. The Hawaiian Islands were formed — and continue forming — the same way.tvb now,tvbnow,bttvb, C: _7 w# F9 v( Y; a( H
. j( r+ F$ x U5 m, r! x公仔箱論壇 公仔箱論壇- E: R0 u4 z* ]$ x0 r) N
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。; x& l0 l" V7 w w4 O5 y9 S
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.
K" P$ t6 a4 ^tvb now,tvbnow,bttvbA 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
e/ X' k: s7 s7 W) c- E: k+ 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。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,
. ~: F+ a2 q$ F( L8 P公仔箱論壇causing avalanches of debris into the crater. |