DK Findout! Volcanoes - Maria Gill

Perched on
a volcanic plug

This church, called Saint-Michel
d’Aiguilhe, was built on top of a plug of
dried lava, which blocked the vent of an
extinct volcano in central France. You

have to walk up 268 steps to visit
the church, which is over
1,000 years old.

EXTINCT

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Sinking islands The short-lived
island caused
When some undersea volcanoes erupt, they release a few countries
enough lava or ash to form a new island. The to fall out.
island may stay there permanently or disappear
within months, washed away by the sea. Other
volcanic islands disappear more gradually, sinking
slowly over thousands of years.

FACT FILE

» Name: Graham

Island, Ferdinandea,
or Julia!

» Status: Active
» Last eruption: 1863
» Location: Between

Sicily (now part of Italy)
and the coast of Africa, in
the Mediterranean Sea

Claiming the isl
and

Where’s my island gone? Changing flags
In its short life, Graham Island was
In 1831, a new volcanic island rose out of the Mediterranean renamed twice and claimed by the
Sea near Sicily. A month later, a British sailor planted a British, Sicilians, and French. The
Union Jack flag in its cooling lava, claiming it for the UK. island briefly reappeared in 1863.
He named it Graham Island. Soon after, the Sicilians claimed
it for themselves, renaming it Ferdinandea. Then, the French
decided it was theirs, calling it Julia. While these countries
quarrelled over the island, it sank back into the sea!
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Disappearing beauty ! WOW!

Bora Bora is one of the most beautiful islands in Bora Bora is
the world. It formed about 4 million years ago sinking by 1 cm
from the eruption of an underwater volcano. (0.4 in) every
A ring-shaped coral island, called an atoll, grew
around it (see below). The now-extinct volcano 100 years!
is sinking very slowly. One day, the island will
disappear below the sea, leaving the atoll, with
a shallow lake, called a lagoon, inside it.

FACT FILE

» Name: Bora Bora
» Status: Extinct
» Last eruption:

Unknown

» Location: Society

Islands, French Polynesia,
in the South Pacific Ocean

Plants grow
on top of the
coral reef.

How an atoll forms New volcano Sinking island Atoll and lagoon
A coral reef begins After the volcano stops The volcano gradually
An atoll forms when a coral to grow around the erupting, it begins to sinks out of sight,
reef grows around a new underwater slopes of sink, but the coral reef leaving an atoll and
volcanic island in the ocean. a new volcanic island. keeps growing. a shallow lagoon.
The reef builds up from the
skeletons of corals, which 51
are tiny animals. Eventually
it pokes above the sea,
and the island sinks,
leaving an atoll with a
lagoon in the middle.

New islands

Volcanoes under the sea get bigger each time they
erupt. Eventually, their peaks may rise out of the
water as new islands. For thousands of years a
volcano has been growing near the island of Hunga
Tonga in the Pacific Ocean. It suddenly erupted in
2009, spewing huge clouds of smoke and ash high
into the air. It erupted again between late 2014 and
early 2015 and created a brand-new island.

Hunga Ha’apai

Hunga Tonga

Before 2014–15 eruption

After 2014–15 eruption
Before the 2014–15 eruption of the volcano near
Hunga Tonga, there were two little volcanic islands
poking out of the ocean. When the volcano stopped
erupting in 2015, a new area of land had risen out
of the sea between the two islands.

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! WOW! Surtsey, Iceland

A column of In 1963, fishermen aboard a boat
ash blasted out near Iceland noticed smoke coming
of the sea and out of the sea. A day later, a small
island had appeared. The island
rose to 9 km grew in size with further eruptions,
(6 miles) in which ended in 1967. It was named
Surtsey. However, the wind and
the sky. waves have since worn away half
the island. Scientists think Surtsey
might disappear below sea level by
2100. In the meantime, many plants
and animals, including these birds,
have made the island their home.

Kittiw Great black-backed gull

ake

Black guillemot Northern fulmar

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Deep-sea vents

A lot of volcanic activity takes place under Underwater hydrothermal vent
the ocean floor. In the 20th century, scientists The scientific word “hydrothermal”
comes from the Greek words for
discovered hydrothermal vents. These are
openings in the ocean floor that spurt out “water” and “heat”.
billowing clouds of superhot seawater,
rich in a variety of minerals.

Cold seawater
Very cold seawater,
about 2ºC (36ºF),
seeps through cracks
in the ocean floor.

Exploring the sea Yeti crab
This furry deep-
More is known about the surface of the sea crab was only
Moon than the Earth’s ocean floor. To help discovered in 2005.
explore the ocean depths, scientists use small It is blind, lives off
underwater vehicles called submersibles, bacteria, and grows
such as DeepSee, shown here. Some hold a up to 15 cm (6 in) long.
very small crew. Others work without a crew.

Living in hot water

In the 1970s, scientists were amazed
to find many animals and microscopic
life-forms called bacteria surviving in
the pitch-black, scalding-hot, mineral-
rich waters around hydrothermal vents.

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Mineral chimney Black smoker Minerals
Minerals from When a mineral chimney Microscopic life-forms
the hot water releases dark clouds of called bacteria use these
settle to form hot, mineral-rich water, it chemicals, spewed out
fast-growing is called a “black smoker”. from the vents, as their
chimneys. source of energy.
Rising hot water
Water, heated by magma
to temperatures as high
as 400ºC (750ºF), rises up
the hydrothermal vent.

Magma
Seawater travels far
below the ocean floor,
where magma heats it.
On the way back up, it
picks up minerals from
rocks it moves through.

Deep ocean Giant tube worms
scale worm These red-tipped
Just 2.5 cm (1 in) worms grow up
long, this scary- to 2.4 m (8 ft) long.
looking worm They feed on bacteria
shoots out its jaws and hide in their tubes
to catch its dinner. if they are threatened.

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Volcanoes in space

Volcanoes haven’t just shaped the Earth – they’ve also
shaped other planets and their moons in our Solar
System. Many of these volcanoes in space have been
extinct for millions of years, but some are very much
alive. Most of our knowledge about these volcanoes
has been collected by spacecraft called probes.

Mercury Venus Earth Mars

Mercury’s surface Maat Mons Olympus Mons

There are no active volcanoes Venus has more than a Mars has the biggest known
on Mercury any more. Many thousand volcanoes. The volcano in the Solar System.
craters, however, are found on tallest is Maat Mons, which It is called Olympus Mons and
this planet. They were caused is 8 km (5 miles) high. Thick is 25 km (15 miles) high.
by asteroids and comets hitting cloud surrounds the planet, That’s almost three times
Mercury billions of years ago. but scientists can use radar taller than the Earth’s Mount
Lava flows from volcanoes to see its surface. They Everest! Scientists do not
later smoothed the insides think that some of Venus’s yet know if any of Mars’s
of some of these huge craters. volcanoes are still active. volcanoes are still active.

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The New Horizons probe flew by Jupiter’s moon Io in 2007. Exploring the
Solar System

Space probes are robotic spacecraft that are
launched from Earth to explore space. They
take photographs and gather information,
before sending it back to Earth. Some probes
are programmed to orbit, or circle around,
planets and moons. Others gather information
just by flying past, and a few have even made
landings. Probes have helped us understand
the Solar System and have discovered many
volcanoes in space.

Jupiter Saturn Uranus Neptune

Io Enceladus Triton

Hundreds of active volcanoes There are huge geysers on Like Enceladus, Neptune’s
are found on Io, one of Jupiter’s Enceladus, which is one of largest moon, Triton, has
moons. Some erupt explosively, Saturn’s moons. The geysers geysers. They spurt columns
shooting up columns of gas spurt water and gases from of nitrogen and dark dust.
and dust that rise hundreds an ocean that lies hidden The columns can rise 8 km
of kilometres. Others form underneath Enceladus’s icy (5 miles) before being blown
huge craters with great lava crust. This type of geyser away by the wind. They also
lakes. There are also lava flows is also called an ice volcano, leave long dark streaks on
500 km (300 miles) long. or cryovolcano. the moon’s surface.

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Volcano facts INDONESIA
and figures is the country with the most
active volcanoes – 76 have
Volcanoes are a fascinating subject. been observed erupting!
Here are some weird and wonderful
facts you might not know about them!

There are about 1,55 0 active volcanoes in theworld.

There are about 74,000 YEARS

2,000 since a supervolcano,
volcanologists called Toba, in Indonesia,
erupted. It plunged the
in the world today! world into a 10-year-long

cold spell.

20 300,000,000
is the average is the number of people thought
number of Earth’s to live within the range of an
volcanoes erupting active volcano.
on any day.

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20,000,000 tonnes !

(22,000,000 tons) of the poisonous gas
sulphur dioxide were given out by Mount
Pinatubo in the Philippines, in 1991.
The eruption lowered the world’s
temperature by 0.5ºC (1ºF).

60 km (37 miles) Most active volcano

is the maximum height that an ash in the world is Kilauea in Hawaii, USA. This volcano
column can reach after an eruption. has been erupting nonstop since 1983!

Most of this
volcano is
under the sea.

75% 6,893 m e10,204 m
(22,615 ft) Ma(33,476 ft)
is the proportion of
Earth’s volcanoes that Highest peakOjos d Highest from bas
are on the Ring of Fire
in the Pacific Ocean. el Salado, South Am una Kea, Hawaii, U

This volcano’s peak is the The base of this volcano
highest in the air. is deep in the ocean.
59
erica
SA

Glossary crater Bowl-shaped hole in
the top part of a volcano

Here are the meanings of some words that crust Outer layer of the Earth
are useful for you to know when learning cryovolcano Huge geyser
all about volcanoes. seen on distant moons that
erupts water and gas rather
active Word used to describe caldera Huge crater that than molten rock
a volcano that is erupting may form after a very large divergent boundary Where
now or has erupted in the volcanic eruption tectonic plates are moving
last 10,000 years ce Common Era, or all the away from each other
ash Tiny solid particles years after year 0 dormant Word used to
formed from lava blasted cinder cone Type of volcano describe a volcano that has
out of a volcano mainly made of layers of lava not erupted in the past few
atoll Ring-shaped coral fragments called cinders thousand years but could do
island that forms around continental crust Outer layer so in the future
a slowly sinking volcano of the Earth with land on it earthquake Shaking of the
basalt Volcanic rock or lava convergent boundary Earth’s surface caused by
that is rich in the metals iron Where tectonic plates are shifting tectonic plates or
and magnesium moving towards each other volcanic activity
bce Before Common Era, or core Centre of the Earth, eruption When lava, ash,
all the years before year 0 made of iron and nickel rock, or gas shoots or flows
black smoker Volcanic vent out of a volcano
on the seafloor that belches A volcano extinct Word used to
out dark clouds of superhot forms when describe a volcano that
water and minerals magma is will never erupt again
erupted. flood basalt Huge area
of land covered in thick
layers of a type of lava

called basalt

fumarole Hole in the
ground in a volcanic
region from which steam
and gas escape

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geyser Hot spring that plate boundary Where two A tiltmeter
spurts a column of water or more tectonic plates meet measures small
and steam into the air plug Mass of lava that has changes in the
hotspot Place where very hardened and blocked the slope of the land.
hot rock inside the Earth vent of a volcano
rises up as a plume, or column, pumice Lightweight form supervolcano Volcano
into the crust and breaks of dried lava that is full of that could have an eruption
through to form a volcano air bubbles a thousand times greater
hot spring Place in a volcanic pyroclastic flow Eruption than most other volcanoes
region where hot water from of hot gas, ash, pumice, and
underground bubbles up to rocks that moves rapidly tectonic plate Large,
the Earth’s surface down a volcano’s slopes slow-moving piece of the
lahar Mudflow of water Ring of Fire Area around the Earth’s crust
mixed with volcanic ash and edges of the Pacific Ocean
other debris, such as rocks that includes 75 per cent of tiltmeter Instrument that
landslide Sliding of loose soil the world’s active volcanoes measures changes in the
and rock down a steep slope shield Type of volcano slope, or tilt, of the ground.
lava Hot, melted rock that with gently sloping sides It is used to predict volcanic
has come out of a volcano and a shape like an ancient eruptions
lava bomb Big blob of warrior’s shield
lava thrown out during stalactite Piece of rock transform boundary Where
an eruption that cools into that hangs down from the tectonic plates are sliding
rock in midair roof of a cave and looks past each other
magma Hot, melted rock like an icicle
below the Earth’s surface stalagmite Pointed piece tsunami Giant sea wave
mantle Thick layer of hot of rock slowly growing out created by an earthquake
rock between the Earth’s of the floor of a cave or a volcanic eruption
crust and core stratovolcano Large,
mud pot Pool of boiling steep-sided volcano made of vent Opening in the Earth’s
mud in a volcanic region many layers of lava and ash crust out of which lava, ash,
oceanic crust Outer layer of submarine volcano Volcano rock, and gas erupt
the Earth with ocean above it that is completely covered
by the sea volcano Opening in the Earth’s
crust, usually in the shape
of a mountain, out of which
magma, ash, rock, and gas
erupt, sometimes explosively

volcanologist Scientist who
studies volcanoes

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Index

A deep-sea vents 54–55 Hawaii 11, 36
Devil’s Tower (Wyoming, USA) hazards 20–21
aa lava 12, 13 heat suits 42, 45
active volcanoes 5, 48, 58 36 Herculaneum 24–25
algae 33 diamonds 37 hot springs 38, 47
andesite 12 dinosaurs 31 hotspots 7
ash 4, 5 divergent boundaries 9 Hunga Tonga (Pacific Ocean)
ash clouds 21, 28, 29 dormant volcanoes 5, 46, 48
ash falls 20, 47 52–53
ash plumes 29 E Hverir Mud Pots (Iceland) 32
Atlantis 23 hydrothermal vents 54–55
atolls 51 Earth, structure of 6–7
avalanches 20 earthquakes 6, 8, 9, 21 I
electrical storms 21, 40–41
B emergency plans 19 igneous rock 12
Enceladus 57 Io 57
basalt 12, 30–31 Erta Ale (Ethiopia) 11 Irazú Volcano (Costa Rica) 4
black smokers 55 eruptions 4–5, 14–15, 18, 43 islands 36, 50–51, 52–53
block lava 12 extinct volcanoes 5, 48–49
Bora Bora 51 Eyjafjallajökull (Iceland) 28–29 J

C F Jolly, Dr Gill 43
Jupiter 57
calderas 10–11, 46 fissures 5
cameras 44 flamingos 38 K
Canary Islands 36 flood basalts 30–31
cave houses 35 Fly Ranch Geyser (USA) 33 Kilauea (Hawaii, USA) 11, 59
caves 34–35 Fuchi 23 Krakatau (Indonesia) 15
cinder cones 10–11 fumaroles 32–33
climate change 37 L
convergent boundaries 9 G
coral 51 lagoons 51
core, Earth’s 6, 7 gas masks 45 Lake Ilopango (El Salvador) 14
Crater Lake (Oregon, USA) 11 gas, poisonous 27, 59 Lake Natron 38
crust, Earth’s 6, 7, 8 geysers 32–33, 47 Lake Nyos (Cameroon) 26–27
crystals 34 Giant’s Causeway Lake Taupo (New Zealand) 47
landslides 15
D (Northern Ireland) 30 lava 4, 5, 11, 12–13, 45
Graham Island 50 lava bombs 5
dacite 12 Lava Butte (Oregon, USA) 11
Dallol Fumaroles (Ethiopia) 33 H lava tubes 34
Deccan Traps (India) 31 lightning, volcanic 21, 40–41
habitats 38–39 lizards, lava 39
hand glasses 45

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M Olympus Mons (Mars) 56 Surtr 23
Surtsey (Iceland) 53
Maat Mons (Venus) 56 P survival kits 18, 19
macaques, Japanese 38
magma 4, 5, 7, 32 pahoehoe lava 12 T
maleos 39 Parícutin (Mexico) 11
mantle 6, 7 Pele 22 Taupo Caldera (New Zealand)
mantle plumes 7 photography 44 47
Mars 56 pillow lava 12
Mauna Kea (Hawaii, USA) 59 plates, tectonic 8–9 tectonic plates 8–9
Mercury 56 Pliny the Elder 24 tiltmeters 44
Mid-Atlantic Ridge 8, 9 Pliny the Younger 25 Toba Caldera (Sumatra,
mineral chimneys 55 plugs, lava 49
Montserrat 43 Pompeii 20, 24–25 Indonesia) 46, 58
Moon 30 pressure 7, 9 tools 43, 44–45
Mount Aniakchak probes, space 57 transform boundaries 9
pumice 7, 12 Triton 57
(Alaska, USA) 11 pyroclastic flows 5, 14–15, tsunamis 15, 21
Mount Cleveland
21, 25 U
(Alaska, USA) 4
Mount Etna (Sicily, Italy) 11, 41 R underwater caves 35
Mount Fuji (Japan) 11, 23 underwater volcanoes 50,
Mount Merapi (Java, Indonesia) ridges 9
Rift Valley (Africa) 8, 9 51, 52
21 Ring of Fire (Pacific) 8, 9, 59
Mount Pelée (Martinique) 14 rocks, lava 12 V
Mount Pinatubo (Philippines)
S vents 5
59 Venus 30, 56
Mount St. Helens (USA) 16–17, safety 18–19 volcanoes
San Andreas Fault (USA) 8, 9
41 Santorini (Greece) 23 facts and figures 58–59
Mount Tambora (Indonesia) 15 Saturn 57 formation of 9
Mount Vesuvius (Italy) 20, seismometers 44 life of 48–49
shield volcanoes 10–11 types of 10–11
24–25 Siberian Traps (Russia) 31 what is a volcano? 4–5
mud flows 14, 20 sinking islands 50–51 volcanologists 42–45, 58
mud pots 32 space 56–57 Vulcan 22
myths and legends 22–23 Stabiae 24
stalactites and stalagmites 35 W
N Steamboat Geyser (USA) 32
stratovolcanoes 10–11 water 32, 36
Neptune 57 sulphur dioxide 59 worms 55
Nevado del Ruiz (Colombia) 14 supermagnets 37
New Horizons probe 57 supervolcanoes 46–47, 58 Y

O Yellowstone Park (USA) 47
yeti crabs 54
Ojos del Salado (South America)
59

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Acknowledgements

DORLING KINDERSLEY would like to thank: Kathleen Teece for editorial assistance, Alexandra Beeden
for proofreading, and Helen Peters for the index. The publishers would also like to thank Dr Gill Jolly for
the “Meet the expert” interview, Mark Buckley for his geology expertise, and Dan Crisp for his illustrations.

The publisher would like to thank the Response Team (cra). 30 Alamy Images: Photo Library: Philippe Crassous (bl). 56
following for their kind permission to Dennis Frates (cl). 31 Alamy Images: Dinodia NASA: (cra, fcra); JPL / Northwestern
reproduce their photographs: Photos (cl). Corbis: Serguei Fomine / Global University (cl); JPL-Caltech (cla); JPL (c, cla/
Look (br); Sergey Krasovskiy / Stocktrek Images Venus). 57 NASA: (c); JPL / USGS (cl);
(Key: a-above; b-below/bottom; c-centre; (cra). Dreamstime.com: Odua (fcl). 33 Corbis: JPL-Caltech / Lunar & Planetary Institute (cr);
f-far; l-left; r-right; t-top) Christophe Boisvieux (bl); Frans Lanting (ca). NASANewHorizons (t). 58 Dorling
34 Alamy Images: Imagebroker (clb). Kindersley: Dan Crisp (c). 59 Alamy Images:
2 Alamy Images: A & J Visage (bl). Corbis: Photoshot: Xinhua (br). 35 Alamy Images: Greg Vaughn (cra). Corbis: Ed Darack / Science
Frans Lanting (bc). 2-3 Alamy Images: Imagebroker (cl); Lilyana Vynogradova (cr). Faction (bl). NASA: Jacques Descloitres,
Michele Falzone (b). 3 Alamy Images: Tom Corbis: YNA / epa (bc). 36 Alamy Images: MODIS Land Rapid Response Team at NASA
Pfeiffer (cb). Dorling Kindersley: Natural Michele Falzone (cl). Fotolia: Yong Hian Lim GSFC (br). 60 Dorling Kindersley: Dan Crisp
History Museum, London (fcr, fcrb, crb, crb/ (br). 37 Dorling Kindersley: Natural History (tl, bl). 61 U.S. Geological Survey: (tr)
gemstone, cr). Dreamstime.com: Odua (bc). Museum, London (tr/4 uses, tr/5 uses).
4 NASA: (cl). 4-5 Dorling Kindersley: Dan Dreamstime.com: Samotrebizan (bl). 38 Cover images: Front: Dorling Kindersley:
Crisp. 8 Alamy Images: Tom Bean (bl); Martin Alamy Images: epa European Pressphoto Dan Crisp cra, Eden Camp Museum, Yorkshire
Strmiska (tr). 11 Alamy Images: Accent Agency creative account (bl). 39 Alamy fcra, Natural History Museum, London cr, fcr;
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(crb). Dreamstime.com: Craig Hanson / Photo Library: Jeremy Bishop. 43 Alamy Front Flap: Alamy Images: epa European
Rssfhs (cra); Lex Schmidt / Lexschmidt (cla). 12 Images: NG Images (crb). 44 Dreamstime. Pressphoto Agency creative account cl/
Alamy Images: Nature Picture Library (cl); com: Ronald Van Der Beek / Uzuri (c). U.S. (front), Olga Kolos tc/ (front), tc/ (front), A & J
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Alvadorado / COLPRENSA / Xinhua (cla). Getty NASA: GSFC / MITI / ERSDAC / JAROS, and the Flap: Dorling Kindersley: Gary Ombler / The
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Images: Aflo Co., Ltd (tl); Richard Roscoe / Observatory image by Jesse Allen, using All other images © Dorling Kindersley
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Peter Turnley (bl). 28-29 Dreamstime.com: Jeff Rotman (cla). naturepl.com: David Shale
Klikk. 29 NASA: Jeff Schmaltz / MODIS Rapid (bc). 55 Corbis: Ralph White (bc). Science

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