Post on 17-Sep-2018
Mt. Kosciuszko2228(7310 ft)
Mt. Everest(29035 ft)8850
El'brus(18510 ft)5642
Kilimanjaro5895(19340 ft)
Cerro Aconcagua6959(22831 ft)
Vinson Massif(16067 ft)4897
Mt. McKinley(Denali)
(20320 ft)6194
R IN G OF F IRE
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AT
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DG
E
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ST
PA
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I C R
I SE
RID
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MID
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DG
E
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PA
CI F
I C R
I SE
AT
LAN
T IC
PACIFIC
PLATE
PACIFIC
PLATE
CAPRICORNPLATE
COCOSPLATE
AUSTRALIAN
PLATE
NASCA
PLATE
E U R A S I A N P L A T E
JUAN DE FUCA PLATE
SOUTH AMERICAN
PLATE
ARABIANPLATE
SOMALI
PLATE
NORTH AMERICAN
PLATE
A N T A R C T I C P L A T E
NUBIA
PLATE
PHILIPPINEPLATE
INDIAN
PLATECARIBBEAN PLATE
SCOTIAPLATE
AFRICAN PLATE
PACIFIC
PLATE
PACIFIC
PLATE
ARABIANPLATE
CAPRICORNPLATE
JUAN DE FUCA PLATE
SOMALI
PLATE
AFRICAN PLATE
SOUTH AMERICAN
PLATE
NORTH AMERICAN
PLATE
E U R A S I A N P L A T E
CARIBBEAN PLATE
AUSTRALIAN
PLATE
A N T A R C T I C P L A T E
NASCA
PLATE
NUBIA
PLATE
INDIAN
PLATE
PHILIPPINEPLATE
COCOSPLATE
SCOTIAPLATE
Edge of diffuse plate boundary
Edge of diffuse plate boundary
Location uncertain
Loca
tion
unce
rtai
n
Locat
ion uncertai
n
San Andreas Fault
Edge of diffuse plate boundary
Edge of diffuse plate boundary
Location uncertain
Loca
tion
unce
rtai
n
Locat
ion uncertai
n
San Andreas Fault
A R C T I C O C E A N
SOUTH
PACIFIC
OCEAN
NORTH
PACIFIC
OCEAN
NORTH
ATLANTIC
OCEAN
SOUTH
ATLANTICOCEAN
INDIAN
OCEAN
NORTH
PACIFIC
OCEAN
L. Superior
Great BearLake
Great SlaveLake
LakeWinnipeg
L. Huron
L. Michigan L. Ontario
L. Erie
LakeMalawi
LakeTanganyika
LakeVictoria
LakeBaikal
Caspian Sea
A m a z o n
AralSea
Ni le
Me d i t e r r a n e a n S e a
BeringSea
C a r i b b e a nS e a
WeddellSea
NorthSea
BarentsSea
Black Sea
ArabianSea
Sea of
Okhotsk
Philippine SeaSouth
China
Sea
Coral
Sea
Tasman
Sea
Drake P
assage
Bering S
trait
Gulf ofMexico
HudsonBay
BaffinBay
Bayof
Bengal
Bass Strait
Gulf ofSt. Lawrence
Red S
ea
A N T A R C T I C A
A M E R I C A
N O R T H
A M E R I C A
A F R I C A
E U R O P E
A S I A
A U S T R A L I A
S O U T H
G R E E N L A N D
S A H A R A
RO
CK
Y
MO
UN
TA
IN
S
AN
DE
S
HI
MA
L A Y A
AN
DE
S
UR
AL
MO
UN
TA
I NS
A L P S
Hawai‘i
Tahiti
Cape Horn
Cape of Good Hope
K a l a h a r i
D e s e r t
Madagascar
Plateau of Tibet
G O B I
Kamchatka Peninsula
Southern Alaska
San Francisco, CaliforniaLoma Prieta, California
San Fernando, CaliforniaNorthridge, California
Landers, California
GuatemalaMichoac´an,
Mexico
Northern Peru
Northern Bolivia
Southern Chile
Messina, Italy
El Asnam, Algeria
Armenia
Erzincan, Turkey
WesternIran
Northern Iran
Quetta, Pakistan
Latur, India
Yunnan, China
Qinghai, ChinaGansu and Shanxi, China
Tangshan, ChinaFukui, Japan
K¯obe, JapanTokyo, Japan
Kuril Islands, Russia
Mindanao, Philippines
Ízmit, Turkey
Gujarat, India
Southern Alaska
San Francisco, CaliforniaLoma Prieta, California
San Fernando, CaliforniaNorthridge, California
Landers, California
GuatemalaMichoac´an,
Mexico
Northern Peru
Northern Bolivia
Southern Chile
Messina, Italy
El Asnam, Algeria
Armenia
Erzincan, Turkey
WesternIran
Northern Iran
Quetta, PakistanBam, Iran
Latur, India
Yunnan, China
Qinghai, ChinaGansu and Shanxi, China
Tangshan, ChinaFukui, Japan
K¯obe, JapanTokyo, Japan
Kuril Islands, Russia
Mindanao, Philippines
Ízmit, Turkey
Gujarat, India
Denali ParkSouthern Alaska
San Francisco, CaliforniaLoma Prieta, California
San Fernando, CaliforniaNorthridge, California
Landers, California
GuatemalaMichoac´an,
Mexico
Northern Peru
Northern Bolivia
Southern Chile
Messina, Italy
El Asnam, Algeria
Armenia
Erzincan, Turkey
WesternIran
Northern Iran
Quetta, Pakistan
Latur, India
Yunnan, China
Qinghai, ChinaGansu and Shanxi, China
Tangshan, ChinaFukui, Japan
K¯obe, JapanTokyo, Japan
Kuril Islands, Russia
Mindanao, Philippines
Ízmit, Turkey
Gujarat, India
Southern Alaska
San Francisco, CaliforniaLoma Prieta, California
San Fernando, CaliforniaNorthridge, California
Landers, California
GuatemalaMichoac´an,
Mexico
Northern Peru
Northern Bolivia
Southern Chile
Messina, Italy
El Asnam, Algeria
Armenia
Erzincan, Turkey
WesternIran
Northern Iran
Quetta, PakistanBam, Iran
Latur, India
Yunnan, China
Qinghai, ChinaGansu and Shanxi, China
Tangshan, ChinaFukui, Japan
K¯obe, JapanTokyo, Japan
Kuril Islands, Russia
Mindanao, Philippines
Ízmit, Turkey
Gujarat, India
Denali ParkKatmai/Novarupta
Mount St. Helens, Washington
Lassen Peak, California
Soufriere Hills, MontserratMt. Pel´ee, Martinique
Soufri`ere, St. Vincent
El Chich´on, Mexico
Paricutín, Mexico
Santa María, Guatemala
Nevado del Ruiz, Colombia
Quizap´u, Chile
Cerro Hudson, Chile
Surtsey, Iceland Bezymyannaya, Russia
Ksudach, Russia
Pinatubo, PhilippinesTaal, Philippines
Rabaul Caldera, Papua New Guinea
Lamington,Papua New Guinea
Merapi, Indonesia
Kelut, Indonesia Agung, Indonesia
Ruapehu,New Zealand
Grímsv¨otn, Iceland
Reventador, Ecuador
Shiveluch, RussiaKatmai/Novarupta
Mount St. Helens, Washington
Lassen Peak, California
Soufriere Hills, MontserratMt. Pel´ee, Martinique
Soufri`ere, St. Vincent
El Chich´on, Mexico
Paricutín, Mexico
Santa María, Guatemala
Nevado del Ruiz, Colombia
Quizap´u, Chile
Cerro Hudson, Chile
Surtsey, Iceland Bezymyannaya, Russia
Ksudach, Russia
Pinatubo, PhilippinesTaal, Philippines
Rabaul Caldera, Papua New Guinea
Lamington,Papua New Guinea
Merapi, Indonesia
Kelut, Indonesia Agung, Indonesia
Ruapehu,New Zealand
Grímsv¨otn, Iceland
Reventador, Ecuador
Shiveluch, Russia
Ulawun, Papua New Guinea
Katmai/Novarupta
Mount St. Helens, Washington
Lassen Peak, California
Soufriere Hills, MontserratMt. Pel´ee, Martinique
Soufri`ere, St. Vincent
El Chich´on, Mexico
Paricutín, Mexico
Santa María, Guatemala
Nevado del Ruiz, Colombia
Quizap´u, Chile
Cerro Hudson, Chile
Surtsey, Iceland Bezymyannaya, Russia
Ksudach, Russia
Pinatubo, PhilippinesTaal, Philippines
Rabaul Caldera, Papua New Guinea
Lamington,Papua New Guinea
Merapi, Indonesia
Kelut, Indonesia Agung, Indonesia
Ruapehu,New Zealand
Grímsv¨otn, Iceland
Reventador, Ecuador
Shiveluch, RussiaKatmai/Novarupta
Mount St. Helens, Washington
Lassen Peak, California
Soufriere Hills, MontserratMt. Pel´ee, Martinique
Soufri`ere, St. Vincent
El Chich´on, Mexico
Paricutín, Mexico
Santa María, Guatemala
Nevado del Ruiz, Colombia
Quizap´u, Chile
Cerro Hudson, Chile
Surtsey, Iceland Bezymyannaya, Russia
Ksudach, Russia
Pinatubo, PhilippinesTaal, Philippines
Rabaul Caldera, Papua New Guinea
Lamington,Papua New Guinea
Merapi, Indonesia
Kelut, Indonesia Agung, Indonesia
Ruapehu,New Zealand
Grímsv¨otn, Iceland
Reventador, Ecuador
Shiveluch, Russia
Ulawun, Papua New Guinea
Kodiak-Bowie
Cobb
Raton
Guadalupe-Baja
Yel lowstone
Hawai i-Emperor
Samoa
Tahit i-Society
Gambier
Austra l-Cooks
Easter
Louisv i l le
JuanFern ´andez
Gal ´apagos
Tr indade
St . Helena
Walv is Ridge
Bouvet
Crozet
Kerguelen
R ´eunion
Comoros
East Afr ica
Afar
Tibest iUpl i f t
CapeVerde
New England
Bermuda
Azores
Ice land
Carol ine
East Austra l ia
Tasmant id
Kodiak-Bowie
Cobb
Raton
Guadalupe-Baja
Yel lowstone
Hawai i-Emperor
Samoa
Tahit i-Society
Gambier
Austra l-Cooks
Easter
Louisv i l le
JuanFern ´andez
Gal ´apagos
Tr indade
St . Helena
Walv is Ridge
Bouvet
Crozet
Kerguelen
R ´eunion
Comoros
East Afr ica
Afar
Tibest iUpl i f t
CapeVerde
New England
Bermuda
Azores
Ice land
Carol ine
East Austra l ia
Tasmant id
EQUATOR EQUATORDivergent (arrow length is proportional to plate motion speed)
Convergent
Hot spot
Divergent boundaryConvergent boundaryTransform zone
Diffuse plate boundarydeformation zone
Notable earthquakeof the 20th century
20th century earthquakegreater than 6.5 magnitude
Notable volcanic eruptionof the 20th century
Known volcanic eruptionduring the past 10,000 years
Plate boundary Major tectonic event inthe last 100 years
Earthquake
Plate motion
Tectonic feature
Volcanic eruption
EUROPENORTHAMERICA
SOUTHAMERICA
A S I A
AUSTRALIA
ANTARCTICA
AFRICA
NORTHATLANTICOCEAN
SOUTHATLANTICOCEAN
PACIFICOCEAN
INDIANOCEAN
SOUTHAMERICA
NORTHAMERICA
AFRICA
ASIAEUROPE
IndiaAUSTRALIA
TETHYSOCEAN
ATLANTICOCEAN
PACIFIC
OCEAN
ANTARCTICA
India
NORTHAMERICA
SOUTHAMERICA
AUSTRALIA
ANTARCTICA
AFRICA
PANTHALASSIC
OCEAN
TETHY S O C E A N
EURASIA
China
Cimmeria
Wrangellia
PA
NG
AE
A Arabia
China
India
Laurentia andBaltica
Siberia
SOUTH AMERICA
AFRICA
AUSTRALIA
PANTHALASSIC
OCEAN
ANTARCTICA
PALEOTETHYSOCEAN
Arabia
China
LaurentiaSiberia
BalticaSOUTH AMERICA
AFRICA
AUSTRALIA
PANTHALASSIC
OCEAN
ANTARCTICA
G O N D W A N A
Congo
China
Siberia
Baltica
SOUTH AMERICANORTH AMERICA
AUSTRALIA
PANTHALASSIC
OCEAN
P A N N O T I A
Compare the patterns on this tectonics map with the more general Natural Hazards map seen on the following plate. Natural Hazards | Plate 16
CONNECTIONS
After a meteorite impact wiped out the dinosaurs, drifting continental fragments began to collide. Africa pushed into western Eurasia, raising the Alps. India rammed into Asia, creating the Himalayan Plateau and
squeezing Southeast Asia aside. Birds and once tiny mammals grew large and evolved in their own ways on the new continents as today’s spectacular mountains began to rise.
Cracks across Pangaea spread into rifts and began growing into oceans. The Atlantic opened between Africa and North America as the Pacific shrank. New rifts split North America from Eurasia, and South America tore
away from Africa, opening the South Atlantic. To the south, India split away from Africa, with Antarctica and Aus-tralia left alone near the South Pole.
Pangaea drifted north, and 225 million years ago the first dinosaurs roamed a world-continent that stretched almost from Pole to Pole and nearly encircled an ocean called Tethys, ancestor of the Mediterranean. The colliding
plates slowed their movement, ocean floors sank, and cracks began tearing North America away from Africa. The Pacific’s predecessor, the immense Panthalassic Ocean, surrounded the supercontinent.
Some of today’s mountains were formed before continents assumed their present shapes. Laurentia (North America) collided with Baltica (northern Europe) and later with Ava-lonia (Britain and New England). The
tremendous pressure of the collisions caused the northern Appalachians and the Caledonian Mountains to rise along the seams of the growing superconti-nent, Pangaea.
A chunk of Pannotia broke off and drifted north to the Equator, leaving the continent of Gondwana at the South Pole. The breakaway chunk then split into three parts, which would become North America,
northern Europe, and Siberia. Shallow waters became nurseries for the first multicellular animals with exoskele-tons. This fauna diversified rapidly in a burst of evolutionary creativity called the Cambrian explosion.
As part of a long, repeating process, a supercontinent called Rodinia began splitting apart 750 million years ago. Ocean basins opened in the growing rifts between the pieces. Some frag-ments collided, pushing up mountains
where glaciers grew and spread across the globe, twice even cover-ing the Equator. In time the pieces reunited to cover the center of a new polar supercontinent, Pannotia.
Seafloor SpreadingAdjacent oceanic plates slowly diverge at the rate of a few centimeters a year. Along these boundaries—such as the Mid-Atlantic Ridge and the East Pacific Rise—molten rock (magma) pours forth to form new crust (lithosphere).
SubductionWhen two massive plates col-lide, the older, colder, denser one—often the oceanic plate meeting a continental plate—takes a dive. Pulled into the interior of the Earth, it heats up and is reabsorbed into the mantle. Water rising from the subducting plate causes rock above it to melt, causing a volcanic eruption.
accretionAs ocean plates advance on continental edges or island arcs and slide under them, seamounts on the ocean floor are skimmed off and pile up in submarine trenches. The buildup can fuse with continental plates, as most geologists agree was the case with Alaska and much of western North America.
colliSionWhen continental plates meet, the resulting forces can build impres-sive mountain ranges. Earth’s highest landforms—the Himalaya and adjacent Tibetan plateaus—were born when the Indian plate rammed into the Eurasian plate 50 million years ago.
faultingBoundaries at which plates slip alongside each other are called transform faults. An example is California’s San Andreas fault, which accommodates the stresses between the North American and Pacific plates. Large and sudden displacements—strike-slip movements—can create high-magnitude earthquakes.
hot SpotSA column of magma rising from deep in the mantle, a hot spot is a thermal plume that literally burns a hole in Earth’s rocky crust. The result? Volcanoes, geysers, and new islands. Eruptions occur at plate boundaries, such as in Iceland and the Galápagos, as well as within plates, such as the volcanoes of Hawai‘i and the geysers of Yellowstone.
50 million yearS ago100 million yearS ago200 million yearS ag0300 million yearS ago500 million yearS ago600 million yearS ago
ViSualiZing tectonic proceSSeS
a fluctuating earth
The scale of the thing is otherworldly—a jagged range of outsize mountain peaks, towering three kilometers (two miles) above the abyssal plains and stretching shoulder to vertiginous shoulder along more than 64,380 kilometers (40,000 miles) of seafloor. The global mid-ocean ridge system is by far the grandest geological feature of our planet, snaking into every major ocean basin, and yet it was almost entirely unknown until the 1950s.
Early seafloor maps, such as those first printed in National Geographic, revealed a hidden world. They also helped change fundamentally the way we see our planet, by providing crucial early proof for perhaps the most important geological break-through of the past century. The theory of plate tectonics, popularly known as continental drift, holds that rather than being a stable, planetary skin, the continents are more like rafts constantly adrift upon a bed of molten rock. The ocean ridges are the engines of continental drift, the seams along which new seafloor is formed by cooling magma that rises from below, before spreading outward to push the continents slowly but surely around the Earth’s surface. The results range from immediately spectacular events such as volcanoes, earthquakes, and geysers to the slow-motion uplift of mountain chains and vol-canic islands. Over hundreds of millions of years, new ocean crust is formed along the mid-ocean ridges and old ocean crust is recycled along sub-duction zones, as the continents are shifted and resorted across the face of the Earth.
15 15
TECTONICS
The Earth in Motion
Tectonics.indd 1-2 5/18/10 10:49:00 AM