ESSENTIAL NATURAL SCIENCE 2 Unit 9 HOMECONTENTS RESOURCES CLOSE BACK LINKS Internal dynamics of the...

ESSENTIAL NATURAL SCIENCE 2Unit 9

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Internal dynamics of the Earth

CONTENTS

RESOURCES



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CONTENTS

INTERNAL DYNAMICS OF THE EARTH

The interior of the Earth Why the interior is so hot

Characteristics Volcanic eruptions

Volcanic eruptions Volcanic materialTypes of eruptions

Earthquakes

EarthquakesEffectsSeismic waves

Reducing the damages Reducing the damage

Warning systems

Mountain building

Relief featuresDistribution of seismic and volcanic activityInteraction of processes

Rocks

Igneous rocksMetamorphic rocks The rock cycle

Internal heat

PhenomenaEvidence

Tectonic plates

Tectonic plates



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Evidence of the heat from the interior of the Earth

RESOURCES

Why the interior of the Earth is so hot

Characteristics of the interior of the Earth

Phenomena produced by internalenergy

Volcanic eruptions

Eruptions and volcanic material

Types of eruptions

Earthquakes Effects of earthquakes

Reducing the damage

Warning systems Mountain building and relief features

Interaction of internal and external processes

Igneous rocks Metamorphic rocks

Seismic waves

Tectonic plates

Distribution of seismic and volcanicactivity

The rock cycle Links

The interior of the Earth



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Why the interior of the Earth is so hot

Earth today4,000 million years ago4,600 million years ago

solid crust

ocean

liquid outer core

solid inner core(6,000 ºC)

solid mantle

meteorite

metal materialscrust

mantle

nucleusGiant meteorites continually collided with the Earth.

As the Earth heated up, it expanded in size. Metal materials sunk to the centre.



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Characteristics of the interior of the Earth

At a depth of 50 km:• the temperature is 600 ºC• the pressure is 20,000 atmospheres

Temperature and pressure increase with depth.

Rate of increase in temperature:

30 ºC per kilometre

GEOTHERMALGRADIENT



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Tectonic plates



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Tectonic plates

At divergent boundaries, plates move apart.

At convergent boundaries, plates push together.

At transform boundaries, plates slide by each other.

Plates move in three ways.



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Volcanic eruptions

Molten rock and gases are ejected through the Earth’s crust.

Phenomena produced by internal energy

Earthquakes

A violent trembling of the Earth’s crust which lasts a short time and varies in intensity.

Continental drift

Isostasy

Slow vertical movement of the Earth’s crust.

A slow horizontal movement of the continents.



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Formation of a magnetic field

Evidence of heat from the interior of the Earth

Formation of the atmosphere Hot rocks

Hydrothermal phenomena



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Volcanic eruptions

crust

mantle

outer core

inner core

crust

mantle

hotspot

hot spots within the

mantle



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vent

volcanic cone

PYROCLASTICMATERIALS

GASES

LAVA

magma chamber

pipe (conduit)

CLICK TO SEE MORE



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vent

volcanic cone


GASES

LAVA

magma chamber

pipe (conduit)

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GASES

carbon dioxde

water vapour

sulphur gases

carbon monoxide

[close]



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vent

volcanic cone


GASES

LAVA

magma chamber

pipe (conduit)

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PYROCLASTIC MATERIAL

ash

lapilli

volcanic bombs

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vent

volcanic cone


GASES

LAVA

magma chamber

pipe (conduit)

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LAVA

At more than 1,000 ºC, lava is very liquid and flows easily.

At less than 700 ºC, lava is thick and flows slowly.

Bubbles of gas escape gently.

Bubbles of gas splatter and cause explosions.

[close]



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Types of eruptions CLICK ON THE GREEN

BUTTONS TO LEARN MORE.

HAWAIIAN STROMBOLIAN VULCANIAN



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CLICK ON THE GREEN BUTTONS TO LEARN MORE.

STROMBOLIAN VULCANIAN

Types of eruptions

HAWAIIAN

• magma temperature: very high (over 1,000 ºC)• very liquid lava• not very destructive nor explosive

Shield volcano

magma chamber

central ventpipe (conduit)

[close]



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HAWAIIAN STROMBOLIAN VULCANIAN STROMBOLIAN

Types of eruptions

• magma temperature: moderate (700 - 1,000 ºC)• thick lava• explosive pyroclastic material

pipe (conduit)

Stratovolcano (composite volcano)

magma chamber

volcanic conecentral vent

[close]



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HAWAIIAN STROMBOLIAN VULCANIANVULCANIAN

Types of eruptions

• magma temperature: low (less than 700 ºC)• violent, destructive explosions• generally gases and ash are expelled

magma chamber

Dome volcano

volcanic pipe of solidified lava

[close]



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Earthquakes

seismic waves

epicentre

hypocentre (focus)

Earthquakes are caused by a sudden release of energy from the Earth’s crust.



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Effects of earthquakes

Chile (1960)

9.6Richter Scale

hypocentre (focus)

epicentre

landslides

damage to buildings

tsunami

seismic waves



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seismogram

seismograph

Seismic waves

Studying seismic waves

seismic waves

WHAT OTHER INFORMATIONCAN SCIENTISTS LEARN FROM SEISMIC WAVES?



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Seismic waves

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Answer: They can learn information about the internal structure of the Earth.

liquid outer core

solid inner core

lithosphere

tectonic (lithospheric) plates

crust (granite and basalt)

mantle (perioditite)

core (iron)



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Reducing the damage from earthquakes and volcanoes

Risk map

Preparedness

Prediction

Emissions of water vapour and other gases are observed.

Buildings are designed to withstand seismic movement.

low high

Prediction



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satellite

An early warning buoy system receives information about waves, wind and seismic movement.

Warning systems

buoy

Hawaii



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Mountain building and relief features

RELIEF FEATURES OF THE EARTH

HOW RELIEF IS FORMED

The crust thickens.

outer core

mantle

rift valley

Two plates move apart.

rising current

Himalayas

Two plates push together.



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Pyrenees

Betic ranges

20 million years ago

Alboran plateIberian plate

Eurasia


Iberian plateAlboran plate

Ebro massif




Two plates push together. RELIEF FEATURES

OF THE EARTH

GO BACKouter core

mantle

rift

rising current

The crust thickens.

Two plates move apart.



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CLICK ON THE RED DOTS TO LEARN MORE GO BACK



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Continental shelves: areas near the coastline, under the sea, made up of continental crust




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Oceanic (mid-oceanic) ridges: chains of submarine mountains with intense volcanic activity

CLICK ON THE RED DOTS

TO LEARN MORE GO BACK



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Great plains: large extensions of flat land





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Mountain ranges:chains of mountains





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Ocean trenches: the deepest areas of the ocean




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Submarine volcanoescan create volcanic archipelagos.





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Abyssal plains: the largest plains on the planet




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Distribution of seismic and volcanic activity

high seismic activitymoderate seismic activitylow seismic activity

volcanic activity



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Interaction of internal and external processes

Isostatic movement

subsidence (sinking)

upliftThe weight of deposited sediment produces subsidence.

Agents erode and reduce the weight of the lithosphere.



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Igneous rocks

Common igneous rocks

GRANITE PEGAMATITE SYENITE GABBRO

VOLCANIC SCORIA PUMICE OBSIDIAN BASALT

Plu

ton

ic o

r in

tru

sive

ig

neo

us

rock

sV

olc

anic

or

extr

usi

ve

ign

eou

s ro

cks



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Metamorphic rocks

Common metamorphic rocks

Clay minerals

Clay minerals or slate

Clay minerals, slate, or schist

Sandstone with quartz

Limestone

SLATE SCHIST GNEISS QUARTZITE MARBLE

Ori

gin

al r

oc

k a

nd

m

etam

orp

his

mM

etam

orp

hic

ro

ck

increase in temperature

and pressure

intense increase in

temperature and pressure

very intense increase in

temperature and pressure

intense

increase in temperature

and pressure

intense increase in

temperature and

pressure



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The rock cycle

SEDIMENTS

MAGMASEDIMENTARY ROCK

IGNEOUS ROCK

METAMORPHIC ROCK

melting

metamorphism

metamorphismweathering and erosion

weathering

and erosion

we

ath

eri

ng

a

nd

ero

sio

n

co

mp

ac

tio

n

an

d

ce

me

nta

tio

n

melting

mel

tin

g

coo

lin

g



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Links

How do rocks undergo change?http://www.classzone.com/books/earth_science/terc/content/investigations/es0602/es0602page01.cfm?chapter_no=investigation

Observe animations of processes that occur along plate boundaries. http://www.classzone.com/books/earth_science/terc/content/visualizations/es0804/es0804page01.cfm?chapter_no=visualization

The Earth: A living planethttp://www.seed.slb.com/en/scictr/watch/living_planet/index.htm

The rock cycle diagramhttp://www.learner.org/interactives/rockcycle/diagram.html

Animated guide: volcanoeshttp://news.bbc.co.uk/2/hi/science/nature/4972366.stm

Interactives: Volcanoeshttp://www.learner.org/interactives/volcanoes/

Earthquakes http://www.bbc.co.uk/science/hottopics/naturaldisasters/earthquakes.shtml

Rocks and the rock cyclehttp://www.windows.ucar.edu/tour/link=/earth/geology/rocks_intro.html

How earthquakes happenhttp://news.bbc.co.uk/2/hi/4126809.stm

Rockhoundshttp://www.fi.edu/fellows/fellow1/oct98/expert/index.html

Plate tectonicshttp://www.bbc.co.uk/schools/gcsebitesize/geography/platetectonics/

The interior of the Earthhttp://csep10.phys.utk.edu/astr161/lect/earth/interior.html

ESSENTIAL NATURAL SCIENCE 2 Unit 9 HOMECONTENTS RESOURCES CLOSE BACK LINKS Internal dynamics of the...

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