The Visual World Atlas - Facts And Maps Of The Current World

THE VISUAL

WORLD ATLAS

[ FACTS AND MAPS OF THE CURRENT WORLD ]

Mantesh



The Visual
World Atlas

Facts and maps of the current world

The Visual World Atlas [document cartographique] was created and produced by CREDITS
QA International
329 De la Commune West, 3rd Floor Editor
Montreal, Quebec H2Y 2E1 François Fortin
Canada
T : 514.499.3000 Editorial Director
F : 514.499.3010 Martine Podesto

ISBN : 978-2-7644-0889-6 Chief Writers
Julie Cailliau
www.quebec-amerique.com Cécile Poulou-Gallet

© QA International, 2008. All rights reserved. Assistant Writer
Marie-Anne Legault
No part of this book may be reproduced or transmitted in any form or by any means, electronic
or mechanical, including photocopying, recording, or by any information storage and retrieval Cartographer
system, without permission in writing by QA International. François Turcotte-Goulet

Graphic Designers
Anne Tremblay
Josée Noiseux

Layout
Émilie Bellemare
Émilie Corriveau
Mélanie Giguère-Gilbert
Pascal Goyette
Danielle Quinty

Photo Acquisition
Gilles Vézina

Illustrator
Alain Lemire

Computer Graphics
Mathieu Douville

Translator
Kathe Roth

Proofreading
Veronica Schami Editorial Services

Project Manager
Nathalie Fréchette

Preprinting
Julien Brisebois
François Hénault
Karine Lévesque

Human Geography Consultant
Jean-Guy Vaillancourt

Mantesh

The Visual
World Atlas

Facts and maps of the current world

QA INTERNATIONAL

Mantesh

IV : H o w to u se this book

Subject

Each subject covers two to eight pages
and offers a complete comprehension

of the theme addressed.

Introduction

An introductory text gives a basic
overview of the subject.

Explanatory texts

Explanatory texts complement the
visual information.

Legend

A legend describes the symbols
used in the main map.

KEY TO SYMBOLS ON MAP

What it stands for Visual presentation What it stands for symbol Visual presentation
mountain range
plateau summit —
plain and basin —
desert depression —
ocean
sea lake
coastal element
island watercourse
continent
region capital
country
territory geographic reference point
(ISO country code)
city main road

international border

regional boundary

Abbreviated forms of the names of countries comply with the recommendations of the International Organization for
Standardization (ISO), detailed on page 164.

Enlargements HOW TO USE THIS BOOK : V

Portions of the main map are enlarged to Photographs
give a detailed view of certain regions.
The photographs are linked by lines to
the places where they were taken.

Visual tab

A photographic excerpt reminds
you of the chapter within which the
subject falls.

Main map

The main map gives you an
at-a-glance overview of the
theme discussed.

MAIN ABBREVIATIONS USED

Metric Unit Abbreviation U.S. Unit Equivalent

millimeter mm —

centimeter cm 0.4 inches

meter m 3.28 feet

kilometer km 0.62 miles

square kilometer km2 0.39 square miles

cubic meter m3 1.31 cubic yards

cubic kilometer km3 0.24 cubic miles

gram g 0.03 ounces

kilogram kg 2.2 pounds

metric ton t 1.1 short tons

million M the same

billion B the same

degrees Celsius °C 33.8 degrees Fahrenheit

hectopascal hPa 0.03 inches of mercury

liter L 33.8 ounces

million hectares M ha 2.47 million acres

hour, second h, s the same

Boxes kilometer per hour km/h the same

Supplementary information is given in kilowatt-hour kWh the same
secondary maps, illustrations, graphs, and
megawatt MW the same
statistical tables.
degree ° the same

before the Common Era bce
inhabitant
U.S. dollar inhab.
gross domestic product $
gross national product GDP

GNP

VI : INTRODUCTION

We live in an amazing world!
Earth, our blue planet, has a special something that makes it unique: it is home
to life. For millions of years, despite countless natural disasters and wild fluctuations
in climate, life has persisted.
For about the past 150 years, life on Earth, as tenacious as it may be, has come
under increasing threat. The growing impact of human activities on the planet’s
fragile balance is putting its inhabitants at risk.The forecasted ecological catastrophe
can be avoided, if we equip ourselves with the means to do so.
And Earth is worth protecting. Our tiny piece of the Universe offers a panoply
of breathtaking landscapes, from the vertiginous heights of the Himalayas and the
extraordinary aridity of the Sahara to the bursts of color in tropical seas. With so
much beauty and diversity, Earth deserves all of our respect.
In order to respect Earth, we have to know it better. Each region of the world
stands out,whether for its geography, its geology, its fauna, its population, its political
organization, or its economy. You will find out about all of these aspects in The Visual
World Atlas.
Today, all the continents have been explored and uncovered, but the knowledge
that has accumulated makes sense only if it is explained and deciphered. This book
does not present the most minute details on each region, but offers a careful selection
of relevant information that will enable you to discover our world and understand
the phenomena that sweep across it.
The Visual World Atlas provides a complete, detailed overview of Earth. It covers
31 subjects in physical and human geography and offers thousands of statistical
facts concerning the 193 countries of the world. It contains more than 110 thematic
maps, as well as photographs taken all over the world.
With this book in your hands, Earth, in all its diversity, is within your reach.
In a world in perpetual change, The Visual World Atlas gives you the keys to
comprehending the present and grasping the challenges to be met in the future.

Mantesh

Contents : VII

EARTH: A ROCKY PLANET :: 8

10 The Solar System 24 Landforms on the ocean floor

12 The planet Earth 26 Volcanoes

14 The structure of Earth 28 Earthquakes

18 Continental relief features

EARTH: A BLUE PLANET :: 30
32 The world ocean
38 Freshwater

EARTH: A PLANET IN BALANCE :: 42

44 Climates 58 The biosphere

48 Cold environments 62 The conservation of species

50 Arid environments 64 Atmospheric pollution

52 Climatic catastrophes 68 Water and soil pollution

EARTH: AN INHABITED PLANET :: 70

72 The political world 98 Agriculture
78 World population 102 Transportation
82 Languages 106 Inequalities
84 Religions 110 Freshwater resources
86 Sports 1 12 Health
90 Economics 1 14 Illiteracy
96 Energy 1 16 Conflicts

THE CONTINENTS :: 120

122 North America 146 Africa

128 South America 152 Oceania

134 Europe 1 58 Antarctica

140 Asia

161 Glossary
164 Statistical data sources
165 Geographical index
172 Thematic index
176 Photo credits



Earth: A Rocky Planet

Earth is the largest rocky planet in the Solar System. It offers a variety
of ever-changing landscapes. As the immense plates that form Earth’s
crust slowly move toward and away from each other, mountains rise,
oceans open up, volcanoes erupt. Erosion is also constantly shaping
the planet’s relief features: mountains flatten, valleys are dug, coastlines
recede. Observing Earth’s landscapes enables us to understand the
history of our planet, explain its structure, and anticipate its future
transformations.

TOP: Rocky beach, California, United States
LEFT: The Glen Coe Valley, Scotland

EARTH: A ROCKY PLANET 10 : THE SOLAR SYSTEM

The Universe contains an almost unimaginable number of galaxies—no fewer than
100 billion! In the midst of this immensity is our galaxy, the Milky Way. The Solar
System is located on the periphery of the Milky Way. It includes one star, the Sun,
and eight planets, three dwarf planets (Ceres, Eris, and Pluto), more than 160 natural
satellites orbiting these planets, millions of asteroids (small, rocky celestial bodies),
millions of comets (balls of dirty snow), billions of pebbles, and cosmic dust and gases.

The planets of the Solar System

The planets closest to the Sun are rocky planets. They are also called the inner planets,
since they are situated between the Sun and the main asteroid belt. Earth is one of
them. The planets situated outside the main asteroid belt are called the outer planets.
They are gaseous giants, composed mainly of hydrogen and helium.

diameter (km) MERCURY THE INNER PLANETS EARTH MARS
average distance from the Sun (AU) 4,879 VENUS 12,756 6,794
1 AU (astronomical unit) = 149,600,000 km 12,104
period of rotation 1 1.52
mass (relative to Earth) 0.39 0.72
gravity at the equator (relative to Earth) 23.9 hr 24.6 hr
temperature (ºC) 58.6 days 243 days 1 (5.9 × 1024 kg) 0.11
number of known natural satellites 0.055 0.82 100% (9.766 m/s2) 38%
38% 91% –87 to –5
composition of the atmosphere 462 –88 to 58
–173 to 427 0 1, the Moon 2
date of discovery 0 nitrogen, carbon dioxide,
carbon dioxide,
no substantial atmosphere nitrogen oxygen nitrogen
known since antiquity known since antiquity
known since antiquity known since antiquity
Source: NASA

THE ORBITS OF THE PLANETS AND DWARF PLANETS OF THE SOLAR SYSTEM

Sun Mercury Venus Earth Mars Ceres Jupiter Saturn

THE SOLAR SYSTEM : 11

Center of the Milky Way EARTH: A ROCKY PLANET
Our Solar System is situated about 28,000 light-years—that is,
280 million billion km—from the center of the Milky Way.

diameter (km) jupiter THE OUTER PLANETS uranus neptune
average distance from the Sun (AU) 142,984 saturn 51,118 49,528
1 AU (astronomical unit) = 149,600,000 km 120,536
period of rotation 19.19 30.07
mass (relative to Earth) 5.2 9.54
gravity at the equator (relative to Earth) 17.2 hr 16.1 hr
temperature (ºC) 9.8 hr 10.6 hr 14 17
number of known natural satellites 318 95 86%
214% –216 110%
composition of the atmosphere – 148 107% 27 –214
62 –178 13
date of discovery hydrogen, 60 hydrogen, helium, hydrogen, helium,
helium hydrogen, methane methane
known since antiquity helium 1781 1846
known since antiquity
Source: NASA

Uranus Pluto Eris Neptune

12 : the planet earth

Formed 4.6 billion years ago, Earth is the largest of the four rocky planets
in the Solar System. It has a single natural satellite: the Moon. Earth is the
densest celestial body in the Solar System: each cubic meter of the planet
weighs an average of 5.5 metric tons. It is also the only planet that
has vast oceans of liquid water, within which life appeared
3.5 billion years ago.

Kodiak Air
Base (USA)

EARTH: A ROCKY PLANET Lake Manicouagan, Canada Vandenberg Air Virginia Air &
The crater of Lake Manicouagan, in northeast Force Base (USA) Space Center (USA)
Canada, results from the impact of a meteorite Kennedy Space Center/
212 million years ago. Edwards Air Cape Canaveral (USA)
Force Base (USA)
Guyana Space
Earth seen from space Center (Europe)
Alacantara Launch
Earth’s vast oceans, from which it gets its Center (BRA)
nickname “the blue planet,” can be seen from
space. Its continents, with jagged coastlines, are
formed of mountains, deserts, lakes—all relief
features that are visible from space. Observation
satellites can also detect a number of impact craters
(the imprints of collisions between Earth and
meteorites) and forests. Earth observation satellites
are sent into space from launch bases dispersed
around the globe.

Hurricane Iris
Cyclones are visible from space. They form cloud disks
almost 1,000 km in diameter.

THE MOON

The Moon is Earth’s only natural satellite. It makes T H E v i s i ble FA C E O F T H E M O O N
one revolution around Earth in 28 days and always Lunar relief features and landing sites for lunar missions

has the same face turned toward the planet (the

visible face). Its diameter is 3,476 km, and its surface

is pocked with craters produced by collisions with Mare Frigoris

asteroids. Situated only 384,400 km from Earth, MJounrtaes CMauocnatseuss Lacus
the Moon is the most-studied celestial body after Somniorum
our planet. Since the late 1950s, several dozen space 17
215 SerMenairteatis 21
ImMbarriuem

missions, manned and unmanned, have explored it. 13 Rima Brayley ApMeonnntiensus 17 CrMisairuem
PrOocceeallnaurusm Montes HMaoenmtuess
Lunar mission landing sites Carpatus BDuorcskulamnTdranqMuailrleitatis 24 MMaarreginis
6 MSienduisi 20 MSmaryethii
9 InsMualarreum 511 GuRtiemnbaeerg 16

RRiimccaioeli 1 3 12 14

CoMgnairteum 16 Mare
NeMcatarer is Fecunditatis
Lacus Veris Rimae Sirsalis

Apollo (manned missions, USA) Montes Cordillera HuMmaorreum Mare Nubium Rupes Altai
Montes Rook
Surveyor (USA) Vallis Snellius

Luna (USSR) 7 Vallis Rheita

The figure represents the mission number.

Sources: USGS; NASA

THE PLANET EARTH : 13

Plesetsk
Cosmodrome (RUS)

Palmachim Baikonur Svobodny EARTH: A ROCKY PLANET
Air Base (ISR) Cosmodrome (KAZ) Cosmodrome (RUS)

Gando Air Jiuquan Satellite Kagoshima
Base (USA) Launch Center (CHN) Space Center (JPN)
Tanegashima
Taiyuan Satellite Space Center (JPN)
Launch Center (CHN)

Xichang Space
Launch Center (CHN)

Sriharikota Odyssey/Sea Launch
Air Base (IND) launch platform (USA)

Christmas Island
launch base (AUS)

Phytoplankton, offshore of Namibia Lake Balkhash, Kazakhstan E A RT H S E E N BY Satell i te
Artificial satellites allow us to study the development The affluents of Lake Balkhash are visible on
and movement of phytoplankton. satellite images. Launch bases
Artificial satellites, space probes, and
manned vessels

Meteorites
Diameter of impact crater

100–300 km
10–99.9 km
1–9.9 km
0.1–0.9 km
Source: The Earth Impact Database, University of
New Brunswick

Composite image built from data recorded by NASA satellites in 2001

14 : THE STRUCTURE OF EARTH

e interior of our planet, with its extreme pressure and temperature conditions, is still
a mysterious place. It is where minerals are created and metamorphosed through processes
that span millions of years. e immense plates that form Earth’s crust float on the
surface of a mass of partially liquid rock. As these plates collide
with each other, they build mountains and open up oceans.

EARTH: A ROCKY PLANET Plate tectonics NORTH AMERICAN
P L AT E
Although it seems to be immobile,
the land on which we live moves several CARIBBEAN
centimeters each year. India and Asia, for P L AT E
example, are moving toward each other by 4 to 6 cm every year.
COCOS
is phenomenon, called plate tectonics, results from the fact P L AT E
that the lithosphere, the outer layer of Earth, is fragmented into a
dozen huge plates, the tectonic plates, about 100 km thick, that slide NAZCA SOUTH
over the surface of Earth’s mantle. Plate tectonics is responsible for P L AT E AMERICAN
most of the components of Earth’s surface, including oceans, created
when two plates move apart (divergent plates), and mountain ranges P L AT E
(convergent plates) that come into existence when two plates collide.
Sometimes, two plates simply slip against each other along what is called
a transform fault. Although the movement of lithospheric plates is slow and
continuous, it is nonetheless the cause of the most violent and devastating
phenomena on the planet: volcanic eruptions and earthquakes.

PACIFIC
P L AT E

THE TECTONIC PLATES
Edges of the plates

Relative movements between two plates
Divergent plates
Convergent plates
Transform fault

Movement of a plate
Direction of movement of a plate

Sources: USGS; ESRI

ANTARCTIC PLATE

San Andreas Fault, California, United States
Frictions along the San Andreas Fault, at the juncture
of the Pacific and North American plates, cause
frequent earthquakes.

T H E str u ct u re O F E A RT H : 15

Eurasian
P l at e

arabian Pacific EARTH: A ROCKY PLANET
p l at e P l at e

P h i l i pp i n e Se a
P l at e

African
P l at e

Indian-Australian
P l at e

CONTINENTAL DRIFT

In the early 20th century, the German geophysicist and Panthalassa Pangaea
climatologist Alfred Wegener noted that the continents
looked like they might be able to fit together. He Eart h 2 5 0 million year s a g o
observed, for example, that the contours of the west coast
of Africa were an almost perfect match with those of
the east coast of South America. He thus formulated the
hypothesis, demonstrated in the 1960s, that millions of
years ago there was just one huge continent, Pangaea, in a
single ocean, Panthalassa. This supercontinent apparently
broke up gradually, forming new continents and new
oceans that continued to drift on the surface of the globe.
The expansion of the sea floor and plate tectonics are
responsible for the mechanism of continental drift. The
plates carrying continents are moving toward or away from
each other at speeds varying from 1 to 18 cm per year.

E art h today

16 : THE structure OF EARTH formed of three concentric layers—from densest to lightest, core,
mantle, and crust. Each has an individual chemical composition
The interior of Earth and specific physical properties. Earth’s crust, composed of
oceanic crust and continental crust, represents barely 3% of the
It is impossible to have a completely clear picture of Earth’s planet’s volume.
internal structure. However, study of the transformations of the
planet’s surface and analysis of other planets in the Solar System
have supplied much information about the interior of Earth.
Our planet has a total mass of about 6 trillion tons and is

COMPOSITION OF EARTH

silicon (15%)
oxygen (30%)

iron (35%)

EARTH: A ROCKY PLANET other elements (3%) magnesium (13%)
sulfur (2%) nickel (2%)

Most of Earth’s surface consists of The continental crust is 20 to 40 km thick, and
oceanic crust about 10 km thick. up to 70 km thick under mountain ranges.

CROSS SECTION OF EARTH The lithosphere, Earth’s rigid outer part, is
composed of terrestrial crust (continental or
oceanic) and part of the mantle.

In the asthenosphere, the temperature reaches
more than 1,200°C, a temperature at which
rock partially melts. The plasticity of this layer
makes continental drift possible.

Convection currents transport Earth’s
internal heat toward the surface.

The mantle takes up 80% of Earth’s total Volcanic eruption of Etna (Italy), in 2002 >
volume. Composed mainly of volcanic rock, The lava that flows from erupting volcanoes comes
it is in a state of partial fusion (magma) at
from magma rising from Earth’s mantle.
a temperature of about 3,000°C.

Although the core takes up 16% of the volume The outer core is composed of
of Earth, it makes up only 33% of its mass. It molten metal.
contains the heaviest elements on the planet,
The inner core is composed of metals in a solid state,
such as iron and nickel. even though the temperature is above 6,000°C.



18 : CONTINENTAL RELIEF FEATURES

e movements of Earth’s crust and the erosive action of the wind and water shape a

variety of relief features on Earth’s surface, such as mountains, plains, and plateaus.

In spite of the diversity of landforms, all continents have a similar structure, with older

and more recent parts. e continents rest on a bedrock formed of very Mount Barbeau
old rocks dating from the Precambrian Era (4.6 billion to 2,616 m

570 million years ago). Most major bedrock

zones are situated in the center of

the continents. BROOKS RANGE Mount Gunnbjorn
3,694 m

Mount McKinley #KA RANGE MACKENZIE MO Mount Odin
6,194 m 2,147 m

ALAS COAS UNTAINS T M O U N T A Mont d'Iberville
1,652 m
Mount Logan i
5,956 m d
a
CK n a
O a n
R C

EARTH: A ROCKY PLANET INS S h i eld

The landforms of continents CRAASNCGAEDE IES Great LAURENTIANS S
Plains Mount Washington
Mountains are the most prominent of Earth’s relief 1,917 m
features. ey are characterized by more or less steep I A N
slopes, and their altitude depends on their age. Plains are
vast flat areas in which shallow valleys are carved out by Great C H
watercourses. Plateaus are large flat stretches edged by Basin
escarpments, sometimes very steep. Rivers carve encased SNIEEVRARDAA A
valleys, or sometimes gorges or canyons,
into them. Many plateaus are not very high, L
but some, such as the Tibetan Plateau, may
reach more than 3,000 m in altitude. A
Ozark
PlateauP
antic coastal pl
# Colorado P
Plateau
A
n

i

Death Valley a
-86 m

SSI IOEERCORCRRRIAIADEMEMNNATATDADARLRLEEAtl

#SIEDRERLASMUARODRriEzaba, 5,700 m Lago Enriquillo
-46 m

Pico Cristóbal Colón LlanoPico Bolívar
5,776 m 4,981 m

Chimborazo s
6,310 m Guyana Plateau

A ND Pico da Neblina
2,994 m
Amazonia

Huascarán
6,768 m

E ChiquitosGMroastsoo
Highlands
Sajama AltiplaCno O# Brazilian
6,542 m S Plateau

CONTINENTAL RELIEF FEATURES Glacier National Park, United States Bonete Gran Parana Pico da Bandeira
The steep, snowy slopes of the young Rocky Mountains Chaco Plateau 2,890 m
Summits and depressions tower over the landscape of western North America. 6,759 m #
Summit, altitude Ojos del Salado # R SERRA
Depression, altitude DO MAR
6,893 m
D

I

Aconcagua, 6,962 m L

L Pampas

Landforms E

MOUNTAIN RANGES R
Plateaus
Plains and basins A
Patagonia
Altitude Laguna del Carbón
6,000–8,850 m -105 m
5,000–5,999 m
4,000–4,999 m Altiplano, Chile
3,000–3,999 m The Altiplano region stretches through Chile, Bolivia,
2,000–2,999 m and Peru. At more than 3,000 m altitude, it is one of the
1,000–1,999 m highest plateaus in the world.
500–999 m
250–499 m Mount Vinson
1–249 m 4,892 m
–408–0 m

Sources: NIMA; NASA

ELLSW O#RTH MOUNTAINS

Ben Nevis GMROAUMNPTIAAINNS CONTINENTAL RELIEF FEATURES : 19
1,344 m

CAMBRIAN PENNINES Germano-Polish Plain
MOUNTAINS

SUDET Dhaulagiri, 8,167 m

Gerlachovska # Annapurna, 8,091 m
ES D E N N I N E S 2,655 m C A R
VOSGES Grossglockner # # Manaslu, 8,156 m

3,798 m PATHIANS Mount Everest, 8,850 m

JU RA A L P# S Hungarian Cho Oyu, 8,201 m # ##
Basin
## Mount Cervin Lhotse, 8,516 m
CENTRAL Mount Moldoveanu
# #CMANOTUANBSTRIAEGIIRARNRNESADAODlSmE anPzAM2oYnr3,Ro3eP,n14Etec3o0Naa4kPmyE,eomE2aMS,k5A9S2SIMmF oMn42ot,,ne87tC00Bi76nlatmmonc4,4782AG,m9CrPa1o2nrndmoe
INARIC ALPS 2,543 m Makalu, 8,463 m #
LKAN
BA Kanchenjunga, 8,586 m

PINDUSMusala Peak
2,925 m

SIESRIERRARMAONMREEVuANlDAhacén, 3,482 m Mount
A Etna Olympus CHERSKY
SCMAONUDNITNAAIVNISAN 3,323 m 2,917 m VERKHOYANSK

INS Central MOUNTAINS RANGE KOLYMA MOUNTAINS
A Siberian
Plateau
Hvannadalshnúkur Galdhøppigen URAL MOUNT West
2,119 m 2,469 m Siberian

Plain

Central Volga Mount Belukha ONOVY RANGE STANOVOY RANGE
Russian Uplands YABL
Uplands MaPlnacihnurian
A CShSaoAb-t4MtHk0AAhMGSameSGtIlArFGDRhhjiarudz-o4a7yyLmialkeDQeTiaabtdetarSire-aa1as3D,, 3-e-42pmM00rAe80oTnsAuPammsUnltiaRoot5iUnl5MnS,iS6,ahEoM2n4lkubO0h3nUr0atu5NmrAmCs,Ta1ArA3aI7Nr#ZUa4#Samt,ZC,r5dAA4GK8RSDuOUmeChSpaSErsLepBsi#saRinoU-Cn2SaVD58sp,ap6ammi1da0ainnvZ3maSaa,-Ven58rKpga7d1aah8udmunimnndayIP,nAl-daHk1iuKIcnN3PUshAD2S8aMUPNH,nm1aIa#KR2arnAbS6ygRTaL#PaAaAmItiKD7AkAO,MKKR4NPHAUK8#3GoMA2,Sa9N6bn1HeLLmg4dAUe4mTysAN,Ni5Pbl0eSAYa6MAt6iHaLn,uT9mnAALUz8PNNt7aTlSSag-THmt1BQuAeA5aaraNpsi4udiaInamnAmMPi7ne,Pyn5SClaa#doh5tuiKi6enSBtoahamiancushkinuaan
## # EARTH: A ROCKY PLANET
#

Jebel Toubkal T L # MOUNTAINS SURLAANIGMEAN H I WESTERN GHATS China Mount Fuji
4,167 m # Plain 3,776 m
ASIR
#A ## Agrihan
HIJAZ 965 m
Sebkha Tah ARAKAN YOM
-55 m

Plateau TIBESTI Kulul
-75 m
Mount Koussi Deccan ACNONRADMILITLIECRA
3,445 m ENNEDI Denakil HADRAMOUT Plateau Khorat
Plain plain
DARFUR # Lake Assal, -155 m Doda Betta Chuo Yang Sin
-125 m # 2,636 m 2,420 m
FOUTA Jos #
DJALLON Plateau
ETHIOPIAN
MASSIF Kinabalu
ADMAAMSASWIFA y 4,101 m
Batu, 4,400 m
Mount Cameroon ley
Mount Stanley e BARISAN RANGE

4,070 m 5,109 m ft Val Mount Kenya, 5,199 m
Congo Vall Kilimanjaro, 5,892 m

Basin Ri
t
MITUMBA MOUNTAINS Gunung Kerinci
reat 3,805 m Bulu Puncak Jaya M#AOKE MOUN#TAI Mount Wilhelm
Rif Rantekombola 4,884 m 4,509 m

G 3,478 m
t

West NS
rea

G

Angola East
Plateau
Kimberley DILL E R A
Okavango Plateau
Basin
HAMERRASNLGEEY MOUNT COR
DRAKE
NSBERG #MCDONNELL AUSTR AL I A N

Mount Zeil
1,531 m

Lake Eyre, -12 m
Nullarbor Plain
FLINDERS
RANGES

# Mount Kosciusko Ruapehu
2,228 m Mount
2,797 m

Mount Ossa Mount Cook
1,617 m
3,764 m #

NEW ZEALAND
ALPS

Great Rift Valley, East Africa Australian Cordillera, Australia
The Great Rift Valley is an immense graben. The old mountains of the Australian Cordillera, rounded
It stretches about 5,500 km through East and gently sloping, are home to the highest peak on the
Africa and is divided into western and eastern continent, Mount Kosciusko, at an altitude of 2,228 m.
sections, in the African Great Lakes region.

20 : c ontin e ntal R E L I E F F E AT U R E S

The formation of mountains

The uplift of a landform is the result of a complex process: the comprehension of orogenesis (the process of mountain
a single mountain range may be composed of fragments of formation). In fact, the movement of oceanic and continental
oceanic crust, volcanic rock, and metamorphic rock (transformed plates is responsible for the formation of most mountains.
by high pressure and temperatures). These different types of Subduction mountains, such as the Andes, are created when an
rock are generally arranged in strata that have been folded, oceanic and a continental plate come together, while collision
upturned, or even dislocated along faults. With the discovery mountains, such as the Himalayas, are the result of an impact
of the existence of lithospheric plates came great progress in between two continental plates.

volcano

fault

subduction mountains
coastal mountains

EARTH: A ROCKY PLANET continental plate

magma

oceanic plate

accretionary wedge

BETWEE N OCEAN AND continent Subjected to considerable forces, the continental plate folds and
deforms, giving rise to a subduction mountain range  . When the
When an oceanic plate collides with a continent, it slides under the oceanic plate reaches the mantle, the rocks that form it melt and are
continental plate . Oceanic sediments scraped away by this contact transformed into magma  . These molten rocks sometimes rise to the
accumulate in what is called an accretionary wedge  . As the oceanic surface again, where they are expelled by volcanoes  .
plate sinks, the volume of the accretionary wedge increases, to the point
that it sometimes rises above sea level and forms coastal mountains  .

YOUNG MOUNTAINS AND OLD MOUNTAINS

The shape of a mountain depends, in large part, on its age. Formed
by recent tectonic shocks, the youngest mountain ranges on the
planet (Alps, Himalayas, Rockies, Andes, Caucasus) are very jagged,
with steep slopes and pointed summits. Most of them have not
finished rising, since the slow movements of lithospheric plates
continue to reshape the landforms. The Alps, for example, result
from an enormous uplift that took place about 50 million years ago,
when the Eurasian Plate collided with the African Plate. The oldest
mountains (Urals, Appalachians, Australian Cordillera, Drakensberg)
look less rugged: they have been smoothed out by erosion, which
scrapes material from the slopes and deposits it in the hollows. The
Appalachians, created more than 300 million years ago, are among the
oldest mountains in the world.

≥ 145 million years
< 145 million years

c o n t i n e n ta l R ELIE F F EAT U R E S : 21

t h e h ighest summ it s in the wo r ld

summit ALTITUDE mountain range first ASCENT
North America
Mount McKinley 6,194 m Rockies 1913
Mount Logan 5,956 m Rockies 1925
Orizaba 5,700 m Sierra Madre 1848
South America
Aconcagua 6,962 m Andes Cordillera 1897
Ojos del Salado 6,893 m Andes Cordillera 1937
Europe
Mount Elbrus 5,643 m Caucasus 1874
Mont Blanc 4,807 m Alps 1786
Africa
Kilimanjaro 5,892 m isolated volcano 1889
Mount Kenya 5,199 m isolated volcano 1899
Asia
Mount Everest 8,850 m Himalayas 1953 EARTH: A ROCKY PLANET
K2 8,614 m Karakoram 1954
Kangchenjunga 8,586 m Himalayas 1955
Makalu 8,463 m Himalayas 1955
Cho Oyu 8,201 m Himalayas 1954
Dhaulagiri 8,167 m Himalayas 1960
Manaslu 8,156 m Himalayas 1956
Nanga Parbat 8,126 m Punjab 1953
Annapurna 8,091 m Himalayas 1950
Antarctica
Mount Vinson 4,892 m Ellsworth 1966

Caucasus Mountains, Russia
The Caucasus Mountains extend to the southern border of European Russia, between the Black Sea, to the west, and the
Caspian Sea, to the east. They are the highest in Europe, with Mount Elbrus culminating at 5,643 m.

22 : c o n t i n e n ta l R ELIE F F EAT U R E S usually widens by only a few millimeters over a thousand
years. Mountainous massifs, semiarid regions, and areas where
The erosion cycle the surface of the land has been modified by human activity
(clear-cutting, construction of roads and cities, etc.) erode most
Erosion, a process of abrasion, transformation, and degradation, rapidly. The slowest erosion is associated with lowlands where
is a cycle that begins with the gradual ablation of surface the materials are very hard, such as the Canadian Shield.
material and continues with the transportation of loose
particles to where they accumulate in the form of sediment.
Water and wind are the main agents of erosion: through
chemical or mechanical procedures, they profoundly alter the
landscape. The erosion cycle occurs at different paces, but all
are very slow on the human scale: a fissure in a block of granite

TH E EVOLUTION OF A LAN DSCAPE

EARTH: A ROCKY PLANET Fluvial landscapes are transformed by erosion
caused by watercourses. When the landscape
is very uneven, with high peaks and steep
slopes, erosion is very rapid. Watercourses
carve out deep V-shaped valleys and sweep
away much rocky debris.

As erosion continues, the relief features
flatten out: the summits become rounded and
the slopes become gentler. The watercourses
transport less debris and flow more slowly.

After several million years of erosion, the
landscape becomes a peneplain: there are few
relief features and they barely rise above the
base level. The erosion process slows.

base level = sea level

Geological phenomena may cause a sudden
elevation of the terrain. In this case, the
peneplain is raised high above the base level.

elevation of the terrain

Erosion may then begin again: watercourses
once again carve out deep valleys.

Goblin Valley, United States >
These rocky mushroom-shaped columns 2 to 3 m high, also called hoodoos,

rise by the hundreds in Goblin Valley. They were shaped by erosion,
mainly by the wind.



24 : LANDFORMS ON THE OCEAN FLOOR

Landforms on the ocean floor are as diverse as continental landforms. Under the surface

of the ocean, mountains, plains, plateaus, volcanoes, trenches, and canyons form stunning

landscapes and many of these formations are much larger than are those on land. For instance,

vast abyssal plains are crossed by immense mountain ranges, called oceanic ridges, that stretch

almost 70,000 kilometers in length. ese underwater mountain ranges are between 1,000 and

3,000 meters high, and running their entire length is a rift, a central subsidence

plain that forms as the oceanic plates separate. Where

lithospheric plates meet, gigantic oceanic

depressions, trenches, reach depths comparable

to the altitude of the highest

continental peaks. e deepest

point is 11,034 meters, in the

Mariana Trench in the North

EARTH: A ROCKY PLANET Pacific Ocean. -243 m

Aleutian Trench Reykjanes Ridge

Gor a
d Ridge
NORTH
-5,474 m
ATLANTIC
O C E A N id
The oceanic crust d- A t l a n t i c R
-6,792 m g
While the rocks that make up the e
continents may be 3.8 billion years old, -4,131 m Nares Dee-p6,995 m
the rocks that make up the ocean floor
are never older than 200 million years -6,479 m CaTryemnacnh -7,848 m Pue-r8to,6R0ic5omTre
old. New oceanic crust is constantly m -5,581 m
being formed by volcanic activity that NORTH ral nchAmerican -6,128 m
takes place in the oceanic ridges. With PACIFIC Cent EasRt iPdagcei c
a thickness of about 10 km, the oceanic -6,013 m Ridg-e6,647
crust is also much thinner than the OCEAN
continental crust, which is from 20 to Mi
70 km thick.
C h il e-Peru -6,403 m -5,753 m

East Paci c Ridge -6,015 m -7,694 m
-8,073 m
Trench
SOUTH
PACIFIC Chile Rid

OCEAN ge

-5,653 m

Rise -6,618 m -5,813 m

P a ci f ic- A n t a r c t ic

South Sandwich
Trench, -8,163 m

Pillow lava
Magma situated under the oceanic ridge forms pillow lava
when it comes into contact with relatively cold seawater.

LANDFORMS ON THE OCEAN FLOOR : 25

THE OCEAN FLOOR

The continental shelf is the part of the continent Most of the ocean floor is occupied by vast
that extends from 1 to 1,000 km in a gentle slope abyssal plains that begin at the foot of the
continental slope and are at a depth of between
under the ocean. 3,000 and 6,000 m.

Eurasian Basin An oceanic trench is a deep valley that
-5,254 m cuts into the abyssal plain. It may reach
depths greater than 10,000 m.

ARCTIC

OCEAN

Molloy Hole At the end of the continental shelf,
-5,669 m the continental slope is an abrupt

drop-off in altitude to more than
3,000 m in depth.

-3,931 m An oceanic ridge is an underwater
mountain range situated on either side of a

long, deep fissure in the ocean floor.

-694 m An island arc is a string of volcanic islands formed following the EARTH: A ROCKY PLANET
subduction of an oceanic lithospheric plate under
another oceanic plate .

-3,151 m

ril Trench -7,457 m Aleu-ti7a,n77T3remnch

-5,737 m Ku -7,724 m
-9,533 m

-2,954 m -2,276 m RiRdyguekyu -7,743 m
-2,962 m -4,570 m Japan Trench
NORTH
-3,741 m
-5,317 m PACIFIC

-6,533 m OCEAN
-9,780 m
-6,579 m
Cape -7,519 m
Verde
Basin

-2,837 m

-8,767 m

Philippine ench
-5,016 m Trench Marian-a1T1r ,034 m -6,912 m
-10,164 m Yap Trench
-5,626 m -4,119 m

-1,714 m -6,035 m

-7,743 m -7,205 m

-5,862 m

-5,707 m -100 m -7,586 m -8,930 m
-7J,a1v2a5Trmench -9,000 m TreVnitcyha
Mid-Atlantic Ridg e INDIAN Bengal Ridge
Whar
-6,269 m -6,614 m Basin New Hebrid TrTeonncgha
ton -7,334 m es Trench-10,719 m
OCEAN -7,374 m
-4,091 m
-9,779 m
UNDERWATER LANDFORMS
-6,714 m KTerremncahdec
Depth of seas and oceans
Ridge -6,973 m
6,000–11,034 m
SOUTH Cape -6,180 m 5,000–5,999 m
Agulhas Southwest Indian 4,000–4,999 m
3,000–3,999 m
ATLANTIC 2,000–2,999 m
1,000–1,999 m
OCEAN 500–999 m
0–499 m
-6,683 m Source: Scripps Institution of Oceanography, UCSD

Deepest zones
Depth

Source: Scripps Institution of Oceanography, UCSD

26 : VOLCANOES

Volcanoes may erupt at various locations all over the world, especially at the borders

between lithospheric plates. Violent and spectacular, volcanic eruptions occur when

molten rock, called magma, rises from Earth’s mantle. As it rises, the magma releases

gases, and the pressure increases to the point that Earth’s crust gives way—and there

is a volcanic eruption. About 50 eruptions take place on continents every year;

the number of underwater eruptions has not been counted.

It is possible to observe volcanic eruptions from close

up, since volcanoes do not form haphazardly on

Earth’s surface. Rather, they are situated in

zones where Earth’s crust is fractured or SWEDEN FINLAND RUSSIA
above hot spots, where magma has NORWAY MONGOLIA
pierced the crust.
ESTONIA

LATVIA
LITHUANIA
DENMARK

IRELAND KUINNGITDFEORDAMSNWCEITBNZEELLLRDULXANGIDETLARIEMLYAAUNCSYZTSERVCIANH BELARUS Unzen Volcano, Japan
POLAND Despite an order to evacuate the valley, there were
43 deaths when Unzen Volcano erupted in 1991.
EARTH: A ROCKY PLANET REP. SVK UKRAINE

HUNGARY VIETNAM
HRV ROMANIA MOLDOVA
AND MCO SMR BIH SCG
SPAIN ALBMKD BGR UZBEKISTAN
VAT GEORGIA KYRGYZSTAN
PORTUGAL ARMENIA AZERBAIJAN
GREECE TURKEY TURKMENISTAN
TAJIKISTAN

TUNISIA MALTA CYPRUS SYRIA IRAQ CHINA
LEBANON
MOROCCO GAZA STRIP WEST BANK I R A N AFGHANISTAN

ALGERIA LIBYA ISRAEL JORDAN KUWAIT PAKISTAN NEPALBHUTAN
EGYPT BAHRAIN UNITED I N D I A BANGLADESH
WESTERN QATAR ARAB
SAHARA (MA) EMIRATES

How volcanoes work SAUDI ARABIA OMAN BURMA
LAOS
MAURITANIA

Hot, light magma from Earth’s mantle SENEGAL MALI NIGER YEMEN THAILAND
GAMBIA CAMBODIA
CHAD SUDAN ERITREA
rises toward the surface from the magma GUINEA-BISSAU GUINEA
chamber in which it had accumulated. SIERRALEONE BURKINAGHANA Lake Nyos DJIBOUTI
FASO BENIN (volcanic), 1986
LIBERIA NIGERIA
CÔTE
Over time, the buildup of material pushes D'IVOIRE CENTRAL AFRICAN REP. ETHIOPIA SRI LANKA
the magma into the pipe and brings it to the SOMALIA MALDIVES BRUNEI
TOGO Lake Monoun MALAYSIA
CAMEROON (volcanic), 1984
EQUATORIAL GUINEA RWANDA UGANDA SINGAPORE
INDO
SAO TOME GABON Nyiragongo, KENYA Marapi, 1979

surface, where it overflows the crater in the form AND PRINCIPE CONGO1977 and 2002 SEYCHELLES
DEM. REP.
OF THE CONGO BURUNDI

of lava. e eruption plume is composed of cinders , lava TANZANIA Galunggung, 1982

, and rock debris, which are ejected above the crater. e ANGOLA MALAWI COMOROS Dieng Volcanic Complex, 1979
magma that does not reach the surface sometimes penetrates Merapi, 1994
a layer of rock of a different type and solidifies ; this ZAMBIA MOZAMBIQUE MADAGASCAR
phenomenon is called intrusion. ZIMBABWE MAURITIUS Kelut, 1966 and 1990
Semeru, 1981
VOLCANISM
Rinjani, 1994

NAMIBIA BOTSWANA

SOUTH SWAZILAND Volcanic eruptions
AFRICA LESOTHO Eruptions after 1965
causing more than 10 deaths
Fumaroles are plumes of Lava, which may reach a (named on the map)
burning gas. temperature of 1,000°C, flows Eruptions that took place between the
down the slopes of the volcano at beginning of the Common Era and today
Heated by the nearby magma, an average speed of 300 m/h. Eruptions that took place between 8000 BCE
underground water is expelled and the beginning of the Common Era
Magma is composed of molten
in the form of steam spouts rocks and gas. It is subjected to Sources: Smithsonian Institution, Global
called geysers. extremely high pressure, and it Volcanism Program; Em-dat
is very hot.
Number of victims per country
(dead, injured, and displaced)

≥ 1,000,000
100,000–999,999
10,000–99,999
1,000–9,999
< 1,000
no victims

Source: Em-dat

Edges of lithospheric plates

The Paci c Ring of Fire
Sources: USGS; ESRI

HOT SPOTS VOLCANOES : 27

Hot spots occur in the middle of oceanic or continental plates and not THE PACIFIC RING OF FIRE
at the edges between plates. Pockets of magma rise from Earth’s lower
mantle toward the surface and pierce the lithospheric plate. While the Usually, volcanoes emerge along the edges of lithospheric plates,
lithospheric plate continues to move, the hot spot, still active, remains forming an island chain. One of the best known is the Pacific Ring of
in one place and continues to pierce Earth’s crust, creating a string of Fire, which contains many of the world’s volcanoes. e Ring of Fire
volcanic islands. e Hawaiian Archipelago is one example. includes the volcanic archipelagos of the Aleutian Islands, Japan, and
the Philippines.

GREENLAND (DK)

A L E U T I A N A R C H I P E L A G O (US) CANADA EARTH: A ROCKY PLANET

Saint Helens, 1980
UNITED STATES

NORTH KOREA JAPAN
SOUTH KOREA

Unzen,
1991

HAWAIIAN MEXICO BAHAMAS
ARCHIPELAGO (US)
Popocatépetl, El Chichón, CUBA
1997 1982 DOMINICAN ANTIGUA AND BARBUDA
REP. Soufrière, 1997
HAITI DOMINICA
JAMAICA SAINT LUCIA
Pinatubo, 1991 GUATEMALA BELIZE HONDURAS KNA BARBADOS
Taal, 1965 TRINIDAD AND TOBAGO
Mayon, 1993 EL SALVADOR NICARAGUA VCT GUYANA
PHILIPPINES COSTA RICA GRENADA FRENCH GUIANA (FR)

PALAU MARSHALL IS. Arenal, 1968 PANAMA VENEZUELA SURINAME
Awu, 1966 MICRONESIA
Nevado del Ruiz, 1985
ECUADOR COLOMBIA
Galeras, 1993

NESIA PAPUA NAURU KIRIBATI PERU
TIMOR NEW GUINEA SOLOMON IS. TUVALU BRAZIL
LESTE

VANUATU FIJI SAMOA BOLIVIA
TONGA
PARAGUAY
AUSTRALIA CHILE

ARGENTINA
URUGUAY

THE MOST LETHAL VOLCANIC ERUPTIONS SINCE 1980

NEW DATE LOCATION VOLCANO TYPE OF ERUPTION NUMBER OF DEATHS
ZEALAND 21,800
1985 Colombia Nevado del Ruiz explosive 1,746
VOLCANIC ERUPTIONS 640
1986 Cameroon Lake Nyos (volcanic) emission of carbon dioxide 200
ere are two main types of volcanic eruptions: 192
effusive and explosive. Effusive eruptions involve 1991 Philippines Pinatubo explosive 100
flows of very fluid lava and free gas emissions 90
from volcanoes that usually have gentle slopes. 2002 Dem. Rep. of the Congo Nyiragongo effusive 79
Explosive eruptions are more formidable and 58
usually involve volcanoes with steep slopes. 1981 Java (Indonesia) Semeru explosive 43
Very thick, viscous lava blocks the escape 37
of gases in the magma chamber, so that the 1982 Mexico El Chichón explosive 33
pressure increases inside the volcano to the 32
point that it causes explosions accompanied 1980 United States Saint Helens explosive
by expulsions of rock, lava, and cinders over
hundreds of kilometers. 1993 Philippines Mayon explosive

1994 Java (Indonesia) Merapi explosive

1991 Japan Unzen explosive

1984 Cameroon Lake Monoun (volcanic) emission of carbon dioxide

1990 Java (Indonesia) Kelut explosive

1997 Montserrat Soufrière explosive

28 : EARTHQUAKES Mantesh

Earthquakes, also known as seisms, are produced when there is a sudden tremor

on the surface of Earth due to a discharge of energy issuing from the depths of the

planet. e movement of lithospheric plates and the enormous tensions that

accumulate at their meeting points are directly responsible for

seismic activity. Earthquakes therefore take place mainly

along faults in Earth’s crust, at the edges of the plates.

ere are almost 1 million GREENLAND (DK)

tremors around the planet each

year, but only just over 5% of

them are felt. When they occur

in urban areas, earthquakes CANADA
cause disasters, sometimes

killing thousands of people.

EARTH: A ROCKY PLANET Almost 830,000 people died during the most lethal

earthquake in history, which shook northern China UNITED STATES

in 1556.

MEXICO BAHAMAS

CUBA ANTIGUA AND BARBUDA
DOMINICAN DOMINICA
SAINT LUCIA
HAITI REP.
JAMAICA BARBADOS
The Richter scale BELIZE HONDURAS KNA TRINIDAD AND TOBAGO
Guatemala City, 1976 GUATEMALA NICARAGUA VCT
Invented by the American geophysicist Charles Francis Richter, the COSTA RICA GUYANA
Richter scale measures the magnitude of an earthquake—that is, the EL SALVADOR GRENADA FRENCH GUIANA (FR)
amount of energy that it releases. Each whole number on the scale
corresponds to an intensity 32 times higher than the preceding number. Managua, 1972 PANAMA SURINAME

us, a magnitude 6 earthquake is 32 times more powerful than a VENEZUELA
magnitude 5 earthquake. Earthquakes of a magnitude above 4 are felt by
most people; those with a magnitude above 5 cause damage. Earthquakes COLOMBIA
of a magnitude above 8 cause total destruction of inhabited zones. ey
are rare, occurring fewer than four times a year. ECUADOR

THE MECHANISM OF EARTHQUAKES PERU BRAZIL
Chimbote, 1970

BOLIVIA

PARAGUAY
CHILE

Valparaiso, San Juan, 1944
1906 URUGUAY

Chillán, 1939 ARGENTINA

The epicenter is the region on the surface seismic waves EARTHQUAKES
directly above the focus, the initial point of Magnitude of earthquakes occurring
since 1900
rupture deep within Earth. Earthquakes that caused more than
10,000 deaths are named.
plate movements fault
9–9.5
plates 2. When the tension becomes too great, an 3. Usually, the earthquake is strongest and the 8–8.9
immense quantity of energy is suddenly damage is greatest at the epicenter. After the 7–7.9
1. As lithospheric plates move, they compress released in the form of seismic waves that earthquake, the affected region undergoes a 6–6.9
and expand the rock, subjecting it to propagate to the surface, producing a series morphological alteration, since the two plates, 5–5.9
considerable tension and friction. At this of tremors of Earth’s crust. still side by side, are slightly displaced. 4–4.9
stage, nothing moves. The edges of the Source: Em-dat
plates remain immobile against each other
while the tension increases. Edges of lithospheric plates

Sources: USGS; ESRI

EARTHQUAKES : 29

Izmit, 1999 GEORGIA UZBEKISTAN Earthquake in Kobe, Japan
Spitak, 1988 An earthquake with a magnitude
Erzincan, 1939 Qazvin, TURKMENISTAN TAJIKISTAN of 6.9 on the Richter scale caused
TURKEY ARMENIAAZERBAIJAN 1962 PAKISTAN more than 5,000 deaths in the Kobe
Gilan Province, Ashgabat, 1948 region of Japan in January 1995.
Tien Shan, 1907
1990
Khorosan Province,
1968

CYPRUS SYRIA

LEBANON Tabas, 1978 AFGHANISTAN
IRAN
IRAQ

GAZA STRIP WEST BANK

ISRAEL Quetta, 1935
PORTUGAL Bam, 2003
EGYPT GHANA KUWAIT
SAUDI ARABIA
BENIN JORDAN
ICELAND

SWEDEN FINLAND RUSSIA
NORWAY
ESTONIA
DENMARK LATVIA
LITHUANIA

IRELAND UNITED NLD POLAND BELARUS
KINGDOM
BEL GERMANY
CZECH
FRANCE LUX LIE REP. SVK UKRAINE KAZAKHSTAN
SWITZERLAND
AUSTRIA HUNGARY EARTH: A ROCKY PLANETMONGOLIA
ITALY SVN HRV ROMANIA
VIETNAM
AND MCO SMR BIH SRB BGRMOLDOVA Anshan, 1975
AvezzaVnAoT , MNE MKD
1915 KYRGYZSTAN
ALB
SPAIN GREECE NORTH
Gansu Province, KOREA JAPAN Kanto Plain,
1932 Qinghai 1923
Messina, Tangshan, 1976 SOUTH
TUNISIA MALTA 1908 Province, 1927 KOREA
Agadir, 1960 Sichuan
Muzaffarabad, 2005 Kangra CHINA Province, 1933
MOROCCO District, 1905 Sichuan
Sichuan
Province, 2008 Province, 1974
BHUTAN
ALGERIA LIBYA NEPAL Guangdong
EGYPT Province, 1918
WESTERN QATAR UNITED
SAHARA (MA) BAHRAIN ARAB INDIA BANGLADESH
SAUDI EMIRATES BURMA Tonghai, 1970
ARABIA LAOS
MAURITANIA OMAN Gujarat, 2001

CAPE VERDE MALI NIGER ERITREA

SENEGAL NIGERIA CHAD YEMEN THAILAND
CAMEROON CAMBODIA
GAMBIA BURKINA SUDAN DJIBOUTI
BRUNEI
GUINEA- GUINEA FASO MALAYSIA PHILIPPINES
BISSAU
SIERRA LEONE CÔTE SINGAPORE MARSHALL IS.
LIBERIA D'IVOIRE CENTRAL ETHIOPIA SRI LANKA PALAU MICRONESIA
AFRICAN REP. SOMALIA
TOGO MALDIVES

UGANDA Sumatra, 2004

EQUATORIAL GUINEA RWANDA KENYA

SAO TOME GABON NAURU KIRIBATI
AND PRINCIPE SOLOMON IS. TUVALU
CONGO DEM. REP. SEYCHELLES INDONESIA
OF THE CONGO BURUNDI

TANZANIA PAPUA
NEW GUINEA
TIMOR
MALAWI COMOROS LESTE

ANGOLA

ZAMBIA MOZAMBIQUE VANUATU FIJI SAMOA
ZIMBABWE TONGA
MADAGASCAR MAURITIUS
NAMIBIA
BOTSWANA

SWAZILAND AUSTRALIA

SOUTH LESOTHO
AFRICA

THE MOST LETHAL EARTHQUAKES SINCE 1900

DATE REGION AFFECTED MAGNITUDE NUMBER OF DEAD NEW
December 26, 2004 ZEALAND
Sumatra (Indonesia) 9.0 283,106
July 27, 1976 (earthquake and tsunami)
May 22, 1927
December 16, 1920 Tangshan (China) 7.5 at least 255,000
September 1, 1923
October 5, 1948 Qinghai (China) 8.3 200,000
December 28, 1908
Gansu (China) 7.8 200,000
October 8, 2005
Number of earthquake victims May 12, 2008 Kanto (Japan) 7.9 143,000
by country since 1900 December 25, 1932
(dead, injured, and displaced) May 31, 1970 Ashgabat (Turkmenistan) 7.3 110,000
June 20, 1990
≥ 10,000,000 May 30, 1935 Messina (Italy) 7.2 85,000
1, 000,000–9,999,999 (earthquake and tsunami)
100,000–999,999
10,000–99,999 Northern Pakistan 7.6 80,360
1,000–9,999
< 1,000 Sichuan (China) 7.9 at least 80,000
Borders of country groups
(ex-USSR and ex-Yugoslavia) Gansu (China) 7.6 70,000

Source: Em-dat Peru 7.9 66,000

Western Iran 7.7 45,000

Quetta (Pakistan) 7.5 45,000



Earth: A Blue Planet

Almost three-quarters of Earth’s surface is covered with water. The
abundance of liquid water, which distinguishes Earth from all other
planets in the Solar System, has earned it the nickname “blue planet.”
The four oceans and dozens of seas that form the world ocean contain
salt water, while the planet’s glaciers and ice caps contain freshwater.
Freshwater constantly circulates through the huge reservoirs that are
the oceans and seas, inland waters, the atmosphere, and the biosphere.
However, access to it is very uneven from one region to another.

TOP: Falkland Islands, in the South Atlantic Ocean
LEFT: Iceberg, off Antarctica

32 : THE WORLD OCEAN

Only 30% of Earth’s surface is exposed land. e rest is covered by a huge body of salt

water with a volume of more than 1 billion cubic kilometers: the world ocean.

Twice a day, the oceans of the globe rise and fall by several meters. Tides are

caused by the gravitational pull of the Moon, and to a certain extent Ellesmere Is.

of the Sun, on our planet. e seas and oceans also move

in waves—undulations of the surface of the BEAUFORT SEA Prince Devon Is.
Patrick Is. Melville Is.

water generated by the wind. Banks Is. Prince of Baf n Bay Greenland
Amundsen Gulf Wales Is.
Ocean currents, on the other Victoria Is. Baf n Is.
Bering

hand, are movements of huge Strait ARCTIC POLAR CIRCLE
Davis Strait
masses of ocean water along ch.

very precise routes. Nunivak Is. Gulf of Hudson Bay
Kodiak Island Alaska

Aleutian Is. Turks and Caicos Is.
Great Inagua Is.

Queen Charlotte Is. Hispaniola Puerto British Virgin Is. Anticosti Is.
Rico Anguilla Newfoundland
EARTH: A BLUE PLANET Vancouver Is. Barbuda
St. Pierre and Miquelon
Saint Croix Is. Antigua
Grande-Terre
CARIBBEAN SEA Montserrat Marie-Galante
Martinique

Vast stretches of salt water NORTH Aruba St. Vincent Azores
PACIFIC Margarita Is. Tobago
e world ocean is divided by the continents Guadaloupe NORTH
into four main regions (Pacific, Atlantic, OCEAN Roca Alijos Trinidad ATLANTIC
Revillagigedo Is.
Bermuda OCEAN

Indian, and Arctic) and many smaller Hawaii ar TROPIC OF CANCER Grand Bahama Is. Abaco Is.
basins, the seas, most of which are shallow SARGASSO
Gulf of Mexico SEA
AndrosCuba
and set back from the oceans. While
Cayman Is.

Bay Is.

marginal seas, such as the South China Sea,

open out to an ocean, enclosed seas, such Clipperton Is. Panama Canal
EQUATOR Cocos Is.
as the Mediterranean, are attached to an Palmyra Atoll
Tabuaeran Is.
ocean by a narrow passage. Some salt lakes Kiritimati Is.

that have no contact with the ocean are also Jarvis Is. Galapagos Is. Fernando de
Noronha Is.

called seas; an example is the Caspian Sea.

Caroline Is. Marquesas Is. SOUTH

French Polynesia PACIFIC

Society Is. Tuamotu Arch. Pitcairn Is. OCEAN Martin Vaz Is.
Cook Is. Tahiti Is. Gambier Is. Trindade Is.
TROPIC OF CAPRICORN
Tubuai Easter Is.

Sala y Gomez Is.

THE MAIN SEAS

SEA AREA MAIN COASTAL COUNTRIES Juan Fernandez Is.

Arabian Sea 3,600,000 km2 Yemen, Oman, Iran, Pakistan, Somalia

South China Sea 3,500,000 km2 China, Taiwan, Philippines, Malaysia, Vietnam Chiloé Is.
Weddell Sea 2,800,000 km2 Antarctica

Caribbean Sea 2,600,000 km2 Venezuela, Colombia, Central American countries, Antilles Wellington Is. Falkland Is. South
Mediterranean Sea 2,510,000 km2 Strait of Magellan Tierra del Fuego Georgia Is.
France, Italy, Greece, Turkey, Egypt, Libya, Tunisia, Algeria, Cape Horn
Bay of Bengal 2,170,000 km2 Morocco, Spain South
Gulf of Mexico 1,540,000 km2 Drake Passage SCOTIA SEA Sandwich Is.
Sri Lanka, India, Bangladesh, Myanmar

Mexico, Cuba, United States

Barents Sea 1,405,000 km2 Norway, Russia ANTARCTIC POLAR CIRCLE
Sea of Japan 970,000 km2 Japan, South Korea, North Korea, Russia
East China Sea 770,000 km2 China, North Korea, South Korea, Japan, Taiwan BELLINGSHAUSEN Alexander Is. WEDDELL SEA
North Sea 570,000 km2 Norway, Denmark, the Netherlands, France, United Kingdom SEA

Red Sea 450,000 km2 Saudi Arabia, Yemen, Erytrea, Sudan, Egypt

Beaufort Sea 450,000 km2 Canada, United States

Black Sea 420,000 km2 Ukraine, Russia, Georgia, Turkey, Bulgaria, Rumania

Persian Gulf 233,000 km2 Iraq, Iran, United Arab Emirates, Saudi Arabia, Kuwait

THE WORLD OCEAN : 33

THE OCEANS

OCEAN AREA VOLUME LENGTH OF COAST DEEPEST POINT
Pacific
Atlantic 165,000,000 km2 707,000,000 km3 135,663 km 11,034 m (Mariana Trench)
Indian
Arctic 82,400,000 km2 323,600,000 km3 111,866 km 8,605 m (Puerto Rico Trench)

ARCTIC BARENTS SEA 73,400,000 km2 292,000,000 km3 66,526 km 7,125 m (Java Trench)
OCEAN
14,000,000 km2 16,700,000 km3 45,389 km 5,669 m (Molloy Hole)

GREENLAND Svalbard Severnaya Zemlya
SEA
LAPTEV SEA
Zemlya New Siberia Is.
KARA SEA

North Cape Novaya EAST SIBERIAN SEA Wrangel Is.
WHITE CHUKCHI
Denmark Jan Mayen SEA SEA
Strait NORWEGIAN SEA

Iceland Gulf of Bothnia

Faroe Is. St. Lawrence Is.
Shetland Is. BERING
SEA
NORTH SEA BALTIC SEA SEA OF OKHOTSK Kamchatka
Great Komandor Is.
Ireland Britain
EARTH: A BLUE PLANET
Corse DRIATIC BLACK SEA CASPIAN Hokkaido
Gilbert IsSEA
Sardaigne AEGEAN SEA OF NORTH
SakhalinJAPAN
M E D I T E R R A Sicily SEA
SumatraNEA Honshu
Crete
GNSEA YESLELAOW PACIFIC
Persian G l CEHAISNTA
Madeira Suez Canal SEA Shikoku OCEAN
Canary Is. RED SEA Kyushu
SEA Ryuky
A Taiwan u Is. Ogasawara Gunto Midway Is.
Marcus Is.
u f ulf of Oman

ARABIAN SEA Bay of PHILIPPINE Wake Is.
Khuriya Bengal SEA
Muriya Is. SOUTH Johnston
CHINA Luzon Atoll
SEA
Gulf of Aden Socotra Guam
Lakshadweep Andaman Is.

Sri Nicobar Is. Mindanao C a r o l i n e I s . a r c h . Senyavin Is.
Lanka Chuuk Is.

Bioko CELEBES Admiralty Is. Howland Is.
SEA
Mentawai Is. BISMARCK New Ireland
Borneo SEA Bougainville Is.
Sulawesi . Baker Is.

JAVA SEA New Britain Choiseul Phoenix Is.
Java
Ascension Is. Zanzibar FLORES BANDA New Guinea Santa Isabel Is. Gardner Is.
St. Helen’s Is. SEA SEA Malaita
Farquhar Is.
ARAFURA Saint Croix Is. Tokelau
Mayotte Agalega Is. Christmas Is. TIMOR SEA Guadalcanal
SEA
INDIAN Cocos Is. Gulf of Wallis Is.
Carpentaria
Mozambique Channel Cargados Futuna Is.
Madagascar Carajos Sh. Vanua Levu American
Viti Levu Samoa

Rodrigues Is. New Caledonia Loyalty Is.

Reunion

OCEAN Australia

Norfolk Is. Kermadec Is.

Cape Great
Agulhas Australian

Bight

SOUTH TASMANIAN North Is.
Chatham Is.
Tasmania SEA

ATLANTIC South Is.

OCEAN Prince Edward Is. Crozet Is. Stewart Is.
Antipodes Is.
Bouvet Is. Kerguelen Is. Auckland Is.
Heard and Campbell Is.
McDonald Is.
Macquarie Is.

SEAS AND OCEANS Bay of Fundy, Canada
Ocean currents This bay, about 290 km long, is famous for its very
high tides, which may rise by 16 m in just a few
Warm hours. This phenomenon is due to the fact that the
Cold bay is shallow and funnel-shaped, narrowing as it
goes inland.
Landmasses
Continents
Islands

Sources: ESRI; NIMA

Edges of the archipelagos
in the Pacific Ocean

34 : THE WORLD OCEAN

the surface te mperature of SEAwater 25–29.9°C SURFACE TEMPERATURE OF SEAWATER
20–24.9°C
Water and the atmosphere are constantly exchanging 15–19.9°C SALINITY OF SEAWATER
energy in the form of heat. The surface temperature of 10–14.9°C
the seas and oceans thus plays a fundamental role in the 5–9.9°C WAVE HEIGHTS
regulation of atmospheric processes. Measurement of 0.1–4.9°C
seawater temperature enables us to follow the evolution of –1.9–0°C Waves unfurling on the beach, Australia >
climatic phenomena, such as El Niño, and ocean currents, A wave about to break on the shore momentarily forms a tube (cylinder
such as the Gulf Stream, and to predict the formation of Source: NOAA
cyclones. Seawater temperature also provides information of air) at its peak.
on the development of phytoplankton and shoals of fish.
The distribution of surface temperatures is linked to hours
of sunlight, which, in turn, depends on the latitude. The
temperature of the oceans ranges from 28°C, near the
equator, to –2°C, in the high latitudes (north and south),
closely following the distribution of solar radiation that
reaches the surface of the water.

EARTH: A BLUE PLANET THE SALINITY OF SEAWATER

The salinity of seawater is the amount of salt dissolved Very high
in the water. On average, seawater contains 35 g of salt High
per liter. The more enclosed the sea, the higher its salinity. Average
For example, salinity is lower than average in the North Low
Pacific Ocean (32 g/l)  , but higher than average in the Very low
Red Sea (40 g/l)  . The Dead Sea is the saltiest body of
water in the world, with a salinity of 330 g/l, and the Baltic Source : NOAA
Sea is one of the least salty, with a salinity of only 8 g/l.
The balance between water evaporation from the oceans
and precipitation is responsible for differences in salinity.
Under subtropical anticyclones such as those in the
Azores , evaporation is very high, and so the seawater
is saltier. On the other hand, the equatorial region is
subjected to strong and frequent rainfall, which results in
a lower salinity level in seawater around the equator .

WAVE HEIGHTS 10–12 m
8–9.9 m
Earth observation satellites are used to measure wave 6–7.9 m
heights. Wave-height data are used to study relationships 4–5.9 m
between sea and air and their meteorological and 2–3.9 m
climatic consequences. Wave height is also very useful 1–1.9 m
information for marine transport and offshore drilling. <1m
In fact, each wave is a shape produced by undulations
created by the wind in the high seas. Near the coasts, the Source: NOAA
wave’s amplitude is determined by the relief features on
the ocean floor. The undulation that moves the wave is
stopped when it hits the shore.



36 : THE WORLD OCEAN continuous action of the sea, rivers, and wind, and it may take a
variety of forms depending on the geological nature of the coast.
Littorals

A littoral is a coastal zone between the low-tide line and the
high-tide line. This landscape is constantly changing due to the

A barrier reef (or barrier island) is a sandbar Deltas form at the mouths of rivers. They Fjords (fjord means “long arm of the sea” in
parallel to the shore at a distance of between result from the accumulation and deposit of Norwegian) are valleys that were carved out
a few and several dozen kilometers. A lagoon sediments carried by watercourses. long ago by glaciers, then invaded by water.
forms behind the reef.
EARTH: A BLUE PLANET

Geologic events have sometimes modified A ria is a fluvial valley that is submerged An atoll is a coral reef that forms around
the coastline by producing faults. This is the following a rise in sea level or a subsidence a volcanic island. It is ring-shaped and
case for very high shore cliffs formed by of land. surrounds a lagoon.
tectonic faults.

Lanzarote, Canary Islands (Spain)
Parts of the volcanic island of Lanzarote, situated in the ocean off southern Morocco,
have coastal escarpments that form cliffs, such as the ones around the Papagayo beach.

THE LARGEST ISLANDS IN THE WORLD THE WORLD OCEAN : 37

ISLAND AREA OCEAN HIGHEST POINT ALTITUDE (m)
Australia 2,228
Greenland 7,740,000 km2 Indian and Pacific Mount Kosciusko 3,733
New Guinea 4,884
Borneo 2,166,086 km2 Arctic Gunnbjorn 4,095
Madagascar 2,876
Baffin Island 792,500 km2 Pacific Puncak Jaya 2,147
Sumatra 3,805
Honshu 725,500 km2 Pacific Mount Kinabalu 3,776
Great Britain 1,344
Victoria 587,040 km2 Indian Mount Maromokotro 655

507,500 km2 Arctic Mount Odin

427,300 km2 Indian Mount Kerinci

227,400 km2 Pacific Mount Fuji

218,100 km2 Atlantic Ben Nevis

217,300 km2 Arctic unnamed summit

EARTH: A BLUE PLANET

38 : FRESHWATER

Barely 2.8% of all water on Earth is freshwater. Most of it is found

in glaciers and pack ice (77%) and in groundwater (22%). e

rest, only 1%, forms the watercourses that irrigate valleys and

plains. As it flows down from mountaintops to the ocean,

freshwater feeds glaciers, lakes, and rivers. e water

evaporates and forms clouds, precipitation

from which feeds watercourses.

For millions of years, this Yukon Macke Great Bear Thelon Nettilling Lake
vast water cycle has created Lake

landscapes by carving out ans zosGreat Slave
ouriLake

valleys, eroding mountains, Fraser Rio Grande. Lake Athabasca
olumbia RivPeace Reindeer lake
akeLSaaskkeatWchienCwneaindpaergLoaskiseson
Nel
and changing shorelines. It nzie Lake WinnipegAlMaibssaissippi

plays an essential role in the redistribution of Della Lake Manitoba OLake Superior
Lake Huron
C Sn Miss Lake Lawrence
Ontario
EARTH: A BLUE PLANET water around the planet. Great Salt Lake Niagara
Michigan St.

e LakeSacram nto Lake Erie Hudson
Yaqui Color hio
ado Ark Susquehanna
ma
Yosemite as
Bra

Rio Grande Usumacinta
de Santiago
Balsas

Lake Nicaragua

Watersheds Magdalena Orino co
Angel Falls
A watershed is a region where all water—precipitation, runoff, and o
groundwater—flows toward a common body of water. A single Tapajos Rio Branc
watershed may contain a number of smaller watersheds. Pu JapuraRio Negro
añónayo les PiresAm azon
tum Ucayali Xingu
Mar rus ira
íba
Pu Te a
Made Araguaia Parn c sco
Tocantins Fran i Glass
deMaDidroes Paragua Juruena
Lake Titicaca y São

THE LARGEST RIVERS RIVERS, LAKES, AND WATERFALLS anaUruguaP a r
Hydrography y
RIVER CONTINENT LENGTH AREA OF WATERSHED
Waterfalls Colorado
Nile Africa 6,670 km 2,870,000 km2 River Chubut
Amazon South America 6,570 km 6,915,000 km2 Lake
Yangzi Jiang Asia 6,300 km 1,855,000 km2
Mississippi–Missouri North America 5,970 km 2,980,000 km2 Edge of watersheds
Jenissei–Angara Asia 5,870 km 2,580,000 km2
Ob–Irtych Asia 5,410 km 2,990,000 km2 Source: Pfafstetter Classification, USGS
Paranà–Rio de la Plata South America 4,880 km 3,100,000 km2
Congo Africa 4,630 km 3,680,000 km2 Freshwater available in the
Amur Asia 4,440 km 1,855,000 km2 main watersheds
Lena Asia 4,268 km 2,490,000 km2 (billions of m3 per year)
Mackenzie North America 4,241 km 1,790,000 km2
Niger Africa 4,184 km 2,090,000 km2 ≥ 250
Mekong Asia 4,023 km 100–249
Volga Europe 3,687 km 810,000 km2 40–99
Murray–Darling Oceania 3,370 km 1,380,000 km2 20–39
1,057,000 km2 10–19
< 10
No data available
Regions with no major watershed
Source: World Resources Institute

Niagara Falls, on the Canada–United FRESHWATER : 39
States border
Although they are not very high, the Yellow River, China
Niagara Falls are spectacular, as they The Yellow River (Huang He in
are wide and have a high discharge rate. Chinese) owes its name to the large
Every minute, 155 million liters of water, quantities of alluvia that it carries.
or the equivalent of 50 Olympic-size
swimming pools, flow over the falls from
a height of about 50 m!

joki Tobol Ob digir Kolyma
Kemi Pecho In
ka Sepik
GlommaLaageDnalalven Lake Ladoga Northern Dvina enisseiJ Vilyuy Fly
ra Angara Lena
Lake Onega Aldan Wallaman
Suir Burdekin
Neva Irtych Amur
Jiang
Lake Vanern Kama
Mahakam
Rh El Ode Vist Lake
sterDnie Dnieper Don Ural Baikal
He
Sein ula Vo Yangzi iang
Loire r Hong XiJiang

be Kapuas
Weserine

e
Krimmler lga Caspian Sea Lake
Balkhash
Garonne e Po Danube Aral Syr EARTH: A BLUE PLANET
Ebro Rhon Sea
B Darya
DueTraoge Gavarnie Kunene Firat AraKkusra Am Tarim Yalu
Guadalquivir Con Issyk Kul
Kizilirmak u Darya Huang
T Murat
Eup r igris Lake Koko Nor
h Urmia

ates Indus

aaDr Shatt al Arab Brahmaputra SalwIerreanwaddy
Oued J

iges
Gan ari
White Nile N i l e Tapti Narmada ahanadM
KrisGhondaav
Sé é Mekong
n gal Blue Nile
Niger Lake Chad Chao Phraya
Lake Lake Tana
Volta enue
Ogooué Lake
Ubangi Turkana Sh
go
ebele
Lake Albert Lake Jubba
Victoria
LukugaLualabaLake
K Tanganyika

i
Ru j
wanza Lake
Malawi

Okavan Zambezi Chire Mania
L mpopo Mtarazi Mangoky

go

i

Orange Tugela arling

D
Murray

Sutherland

THE LARGEST LAKES THE HIGHEST WATERFALLS

LAKE AREA DEPTH ORIGIN WATERFALL COUNTRY HEIGHT
Caspian Sea tectonic
Lake Superior 386,400 km2 1,025 m glacial Angel Falls Venezuela 979 m
Lake Victoria tectonic
Lake Huron 82,100 km2 405 m glacial Mtarazi Zimbabwe 762 m
Lake Michigan glacial
Lake Tanganyika 69,500 km2 82 m tectonic Yosemite United States 739 m
Lake Baikal tectonic
Great Bear Lake 59’800 km2 228 m glacial Tugela South Africa 614 m
Lake Malawi tectonic
Great Slave Lake 57,750 km2 281 m glacial Sutherland New Zealand 580 m

32,900 km2 1,436 m Della Canada 440 m

31,700 km2 1,620 m Gavarnie France 422 m

31,600 km2 82 m Glass Brazil 404 m

29,500 km2 706 m Krimmler Austria 381 m

28,900 km2 614 m Wallaman Australia 347 m

40 : freshwater a young river that continues to flow down the mountain,
following sleep slopes and forming waterfalls . The river
Watercourses carves out deep gorges , and then broadens. Fed by tributaries

Springs, rivers, and lakes form a network with a hierarchy: each , it becomes a large river . As it grows wider, the river forms
flows into a large watercourse, and all watercourses finally flow meanders . Many rivers form deltas at their mouths, and
into the sea. A river such as the Amazon, for example, is fed by finally flow into the sea . Evaporation of water from the
15,000 tributaries. oceans forms clouds, and the water cycle starts over.

Rainwater seeps into the ground and rises to the surface in
the form of a spring , then flows down hills and mountains.
Sometimes fed by meltwater from glaciers , the stream
becomes a torrent ; then, fed by more springs, it becomes

wat e r cy c le

A watercourse that flows into another
is called a tributary.

ear t h : a B L U E p la n e t At the beginning of its course, the river
rushes down mountain slopes, carving
out a bed by creating deep gorges.

Yellowstone National Park, United States
The Lower Falls of the Yellowstone River help
to carve out the riverbed.

oxbow lake

waterfall

A river that feeds a lake is called a
tributary. A river that leaves a lake is

called a distributary.

At the foot of the mountain, the river broadens
and its flow rate slows. The riverbed and banks

continue to erode, carving out a valley.

When it reaches the plain, the river arrives
at its base level and forms meanders,
where it deposits sediments.

Taieri River, New Zealand (South Island)
The meanders of the Taieri River emphasize the
bottom of the Starth Taieri glacial valley.

Lakes FRESHWATER : 41

Surface water usually flows toward the sea, but sometimes it is due to a high evaporation rate and accumulation of dissolved
held back by a depression or dam and forms a lake. Although mineral salts.
most lakes are filled with freshwater, others have high salinity

Water in glacial lakes has accumulated in Tectonic lakes occupy natural basins that The craters of some volcanoes fill with water.
depressions carved out by glaciers and in result from movements of Earth’s crusts These volcanic lakes may also form in valleys
valleys where moraines (glacial deposits), along folds and faults. Many are situated where lava flows hold back water.
some of which are 200 m high, have created below sea level, and some form closed
dams. Most lakes in the northern hemisphere systems with no distributaries.
are of this type.

EARTH: A BLUE PLANET

Oxbow lakes sometimes form in the areas An oasis is formed in a desert when the wind Reservoirs, artificial lakes whose waters are
around rivers. They are formed in meanders, or erodes the ground and exposes the water table. usually held in by dams, supply water for
oxbows, abandoned by the watercourse. Unless Oases also appear where a fault line causes human consumption, irrigation, or production
they are regularly fed by new water, they water to flow toward a particular point. of hydroelectric power.
rapidly dry up.

When a river does not encounter a stronger current as it is
flowing into the sea, it deposits its sediments at the mouth. The
alluvia—sediment deposits—spread out in a fan shape divided into
channels of various widths and shapes. This is called a delta. When
a river encounters a tide that is more powerful than its current, the
sediments that it is carrying disperse. The river’s mouth opens out
like a funnel, and this is called an estuary.

Rio de la Plata estuary, on the border between Nile Delta, Egypt
Argentina and Uruguay At its mouth, the Nile forms a vast delta, clearly visible on
The Rio de la Plata marks the mouth of the Parana and a satellite image.
Uruguay rivers.



Earth: A Planet in Balance

Earth is enveloped in a thin layer of air called the atmosphere.Depending
on the characteristics of air masses around the globe, different regions
have more or less cold, humid, and windy climates. Most weather
phenomena take place in the 15 kilometers of the atmosphere closest
to the ground. This layer of the atmosphere is also home to many living
species. Together, air, water, and a layer of earth form the biosphere,
the habitable part of the planet. Living beings and their environments
form ecosystems. The constant interactions between the components
of an ecosystem maintain its equilibrium. For the last hundred years,
the intensification of human activities has caused air, water, and soil
pollution and threatens to upset the equilibrium of our planet.

TOP: Elk, in Yellowstone National Park, United States
LEFT: Emperor penguins, on South Georgia Island, in the South Atlantic Ocean

44 : CLIMATES

Temperatures, precipitation, humidity, and winds vary enormously from one region

of the world to another. So, Earth has a number of very different climates, each

one with specific atmospheric and meteorological conditions. e distribution

of climatic zones on the surface of the planet depends primarily

on latitude, because sunshine conditions (length of the

day, alternation of seasons, angle of solar rays) play Northice, Greenland
–66.1°C, January 9, 1954
the most important role in

determining climate. Other Arctic Bay, Canada
12 mm

factors are also involved, such

as the lay and orientation of the

land, dominant winds, altitude,

landforms, and ocean currents.

EARTH: A PLANET IN BALANCE Henderson Lake, Canada
6,502 mm

NORTH AND
Death Valley, United States CENTRAL AMERICA

56.6°C, July 10, 1913

TROPIC OF CANCER

Mount Waialeale, EQUATOR
Hawaii

11,684 mm

Climates of the world HERMAL Lloro, Colombia
8,992 mm

T

One-quarter of the planet’s landmass has a EQUATOR
dry (arid or semiarid) climate, characterized
by drought throughout the year. Regions in SOUTH AMERICA
the intertropical zone, between the Tropics
of Cancer and Capricorn, have a tropical Arica, Chile
climate with high temperatures due to regular 0.4 mm
and continual sunshine conditions. e wet
tropical climate has abundant and constant Villa Maria, Argentina
humidity, which encourages growth of the tropical 49.1°C, January 2, 1920
rainforest, while the wet tropical climate with dry
winter has a wet season with monsoon rains and a dry Amundsen-Scott Station Valle de los Patos Superior,
winter season. Temperate regions have a mild climate 20.3 mm Argentina
and four well-defined seasons. Temperate climates
are very diverse, however, as they are influenced by –39°C, July 17, 1972
geographic factors such as altitude, relief features,
and proximity to the ocean. Mountainous regions ANTARCTIC POLAR CIRCLE Vostok
and high plateau zones have a cold climate with low –89.4°C
temperatures. Finally, at the poles, the temperature July 21, 1983
rarely rises above 0°C and the ground remains frozen Vanda Station
for most of the year. 15°C, January 5, 1974

Antarctica
A number of low temperature records have been set
in Antarctica.

CLIMATE TYPES Warm temperate Tropical CLIMATES : 45
Coastal (no dry season, cool summer) Wet
Cold Mediterranean (dry summer) Wet with dry winter Temperature and precipitation records
Ice cap Subtropical humid Maximum temperature (°C) per continent
Tundra Minimum temperature (°C) per continent
Mountain Dry Annual maximum precipitation (mm) per continent
Arid Annual minimum precipitation (mm) per continent
Cold temperate Semiarid
Continental with short, cold summer Regional border
Continental with cool summer Sources: NOAA; Argentina National Weather Service
Continental with hot summer
Verkhoyansk, Russia
ARCTIC POLAR CIRCLE –67.8°C, February 7, 1892

Ust’Shchugor, Russia Oymyakon, Russia
–55°C, over 15 years –67.8°C, February 6, 1933

EUROPE EARTH: A PLANET IN BALANCE

Crkvice, Bosnia
4,648 mm

Seville, Spain Astrakan, Russia
50°C, August 4, 1881 162.6 mm

Ifrane, Morocco El Azizia, Libya Tirat Tsvi, Israel ASIA
–23.9°C 57.8°C 53.9°C, June 22, 1942
Mawsynram, India
February 11, 1935 September 13, 1922 Aswan, Egypt 11,871 mm
1 mm
AFRICA
Aden, Yemen
45.7 mm

Debunja, Cameroon
10,287 mm

TROPIC OF CAPRICORN Cloncurry, Australia
53.3°C, January 16, 1889
INFLUENCE OF RELIEF FEATURES ON CLIMATE
OCEANIA
Some arid regions are dry because of the mountain range
configuration of landforms that surround Mulka, Australia
ANTARCTIC POLAR CIRCLE them. For instance, when a mountain 102.9 mm
range borders a shoreline, it holds back Charlotte Pass, Australia
much of the humidity contained in the –23°C, June 29, 1994
marine air masses. e regions in the lee
of this mountain barrier then receive very desert zone
little precipitation. is is the case for the
Patagonia, Great Basin, and Gobi deserts. dry air

humid air mass

46 : CLIMATES Temperate regions have four alternating seasons: after spring
comes summer, then autumn, and finally winter. Elsewhere in
The Cycle of the Seasons the world, the march of the seasons is less distinct. Subtropical
regions have only two seasons: a dry season and a wet season.
Contrary to popular belief, the cycle of the seasons—that is, the As the seasons pass, the air temperature and atmospheric
periodic changes in climate as the months go by—is due not to pressure vary. Atmospheric pressure is the force that air exerts
the distance of Earth from the Sun but to its inclination: our upon a given surface. It may differ by altitude and temperature.
planet’s axis of rotation is tilted by about 23.5˚ in relation to There are therefore zones of high and low pressure. In general,
the ecliptic (Earth’s orbital plane). This inclination is directly a high-pressure zone, or anticyclone, is responsible for good
responsible for the variation in sunlight conditions, and weather and a low-pressure zone, or depression, is responsible
therefore for the succession of seasons throughout the year. for bad weather.
This also explains why the seasons in the two hemispheres are
opposite: summer in the South always takes place during winter
in the North.

EARTH: A PLANET IN BALANCE E The spring equinox takes place on March 20 or 21 in
N the Northern Hemisphere. The Sun rises exactly in
the East and sets exactly in the West, and day and
W S night are the same length.

Earth is at its aphelion, or maximum distance
from the Sun (152.1 million km), on July 3. The
heat that reigns in the North on this date is due

to Earth’s inclination.

E S E S
N N

W W

The summer solstice is the longest day The shortest day of the year in the
of the year (June 21 or 22 in the Northern Northern Hemisphere is December 21
Hemisphere). The Sun rises high in the or 22. This is the winter solstice. The
sky and warms the atmosphere. sun stays low in the sky and does not
warm the atmosphere much.

On September 22 or 23, day and night are the same On January 3, Earth is at its perihelion,
length. This is the fall equinox in the Northern its closest position to the Sun
(147.3 million km).
Hemisphere. As it does at the spring equinox, the Sun
rises exactly in the East and sets exactly in the West. E

N S

W

African savanna, Kenya INFLUENCE OF LATITUDE ON LENGTH OF DAY
Kenya has two dry seasons, from December
to March and July to October; these summer SPRING WINTER AUTUMN
alternate with two rainy seasons: one from solstice EQUINOX SOLSTICE EQUINOX
April to June, and one in November, which
sometimes extends to mid-December. poles (90˚) 24 hr 12 hr 0 hr 12 hr
12 hr
Schoolchildren in snowsuits, Canada Helsinki (60˚) 19 hr 12 hr 6 hr 12 hr
Canada has four distinct seasons. 12 hr
Winters are particularly cold and snowy. Montreal (45˚) 16 hr 12 hr 8 hr 12 hr

Cairo (30˚) 14 hr 12 hr 10 hr

equator (0˚) 12 hr 12 hr 12 hr

CLIMATES : 47

SEASONAL VARIATIONS IN AIR TEMPERATURE
AND ATMOSPHERIC PRESSURE

AIR TEMPERATURE IN JANUARY AIR TEMPERATURE IN JULY
Average calculated from 1960 to 2005 Average calculated from 1960 to 2005

≥ 25°C ≥ 25°C EARTH: A PLANET IN BALANCE
15 to 24.9°C 15 to 24.9°C
5 to 14.9°C 5 to 14.9°C
–9.9 to 4.9°C –9.9 to 4.9°C
–29.9 to –10°C –29.9 to –10°C
≤ –30°C Sources: NOAA; NCEP; CPC
Sources: NOAA; NCEP; CPC
ATMOSPHERIC PRESSURE IN JULY
ATMOSPHERIC PRESSURE IN JANUARY Average calculated from 1960 to 2005
Average calculated from 1960 to 2005
≥ 1032 hPa
≥ 1032 hPa 1026 - 1031.9 hPa
1026–1031.9 hPa 1020 - 1025.9 hPa
1020–1025.9 hPa 1014 - 1019.9 hPa
1014–1019.9 hPa 1008 - 1013.9 hPa
1008–1013.9 hPa 1002 - 1007.9 hPa
1002–1007.9 hPa 996 - 1001.9 hPa
996–1001.9 hPa < 996 hPa
< 996 hPa Sources : NOAA, CDAS,
Sources: NOAA; CDAS; NCEP-NCAR
NCEP-NCAR

The Angle of Solar Rays

The temperature on the surface On June 21, it is summer
of Earth depends directly on in Algiers, in the Northern
the angle at which the Sun’s Hemisphere.
rays penetrate the atmosphere.
When this angle of incidence is On June 21, it is winter in
small—when the rays graze the Capetown, in the Southern
planet’s surface—the Sun’s energy is Hemisphere.
dispersed. On the contrary, heat is
at its maximum when the Sun’s rays
reach the ground at a 90° angle.

Because of Earth’s inclination,
sunlight reaches the Northern
Hemisphere at a maximum angle
during the Northern summer. At
the same time, the Sun’s rays graze
the Southern Hemisphere and it is
winter in the South.

48 : COLD ENVIRONMENTS

At the highest latitudes, close to the poles, the climate is dominated

by polar air masses, which do not heat up much even during the

long period of summer sunshine. In the center of Antarctica and

Greenland, where the temperature never rises above 0°C, the

ground remains permanently frozen and covered

with a thick ice cap, the continental ice sheet.

e northern edges of Eurasia and North Perito Moreno Glacier, Argentina
Some 30 km long and covering some 250 km2, Perito Moreno is an
America have a more temperate climate: immense continental glacier.

summer temperatures rise above the

freezing point, which enables a BRAZIL
thin top layer of ground to thaw

and tundra vegetation to grow.

EARTH: A PLANET IN BALANCE ARGENTINA Larsen Filchner
Ice Shelf Ice Shelf
The main cold regions Ronne
Ice Shelf Amery
e coldest regions of the Ice Shelf
planet are the poles and Lambert
mountain summits. e poles Glacier
are permanently frozen, but how
far the pack ice stretches toward South Geographic Pole
the middle latitudes varies with
the seasons. e highest mountain AN Ross ANTARCTIC
peaks are also covered with glaciers. TROPIC OF CAPR Ice Shelf South Magnetic Pole

TARCTIC POLAR CIRCLE

COLD ENVIRONMENTS ICORN

Snow, glacier, or continental ice cap NEW- AUSTRALIA
Ice shelf ZEALAND
Average extension of the pack ice in July
(summer at the North Pole, winter at the South Pole)
Average extension of the pack ice in January
(winter at the North Pole, summer at the South Pole)

Source: NSIDC

Pack ice

In the coldest oceans on the planet, especially at the poles, the is layer of ice forms a vast sheet measuring 20 million km2
seawater is covered by a floating layer of ice, a stretch of frozen at its maximum winter extent, but it shrinks a great deal in the
seawater formed when the water temperature falls below –1.9°C. summer. Pack ice is different from the ice shelves (the Ross Ice
Shelf, the Larsen Ice Shelf, etc.) that form the edge of some
ese masses of ice, called pack ice, may be 3 to 4 m thick. In parts of Antarctica. ese are actually floating glaciers, several
winter, Arctic pack ice invades ords, bays, estuaries, and hundred meters thick, contiguous to the continental ice cap.
straits. Hudson Bay is totally icebound during the winter.
Antarctica , covered by an ice cap, is also surrounded by pack ice.