E ARTH’ S I NTERIOR
S ECTION 1
EARTH’S INTERIOR

We never have been able to
visually see into the center of the
Earth.

The largest mine is in South Africa
and is about 3.8 kilometers (2.4
miles) deep.
EARTH’S INTERIOR

Scientists use indirect observation
to observe the Earth’s interior.

Scientists know about the interior
of the Earth from waves produced
by earthquakes.

Seismic waves – waves produced
by earthquakes.
EARTH’S INTERIOR

The speed of the seismic waves
tell scientists about the structure
of the Earth.
EARTH’S INTERIOR
Diagram From:
revisionworld.co.uk
EARTH’S INTERIOR

To begin a journey to the center
of the Earth, you would need to
travel through solid rock.

Temperatures and pressures
would change as you travel
towards the center.
EARTH’S INTERIOR
Temperatures

At first, the temperature around
the surface is cool. Then
temperatures increase rapidly for
several miles and then increase
slowly after that.

For every 40 meters you travel
inward, the temperature rises 1ºC
(33.8ºF).
EARTH’S INTERIOR
Pressure

The deeper you travel into the
Earth, the greater the pressure.

Pressure – the force pushing on a
surface or area
EARTH’S INTERIOR

You will travel through several
layers as you travel through the
Earth.

The Earth is made up of three
main chemical layers.



crust
mantle
core
EARTH’S INTERIOR
Diagram From:
faculty.weber.edu
EARTH’S INTERIOR

Each layer has its own conditions
and materials.
Diagram From:
eoearth.org
EARTH’S INTERIOR

Crust – a layer of rock that forms
Earth’s outer skin

Very thin layer of the Earth.

Includes both the dry land and
the ocean floor.

Thickest under high mountains
and thinnest under the ocean.
EARTH’S INTERIOR

Oceanic crust is made of dense
materials.

Continental crust is made of less
dense materials.

5-40 km thick

Made of oxygen, silicon, aluminum,
calcium, iron, sodium, potassium,
and magnesium
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Crust
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
Mantle – layer of solid, hot rock

Made of oxygen, silicon, iron, and
magnesium.

2,900 km thick

68% of Earth’s mass and 82% of
Earth’s volume
EARTH’S INTERIOR

Traveling farther into the mantle
there is increasing temperatures
and pressures.
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Crust
Mantle
EARTH’S INTERIOR

The core makes up about 33% of
the Earth’s mass but only 15% of
the Earth’s volume.

The core is VERY dense.

Made of iron and nickel

Temperatures range from 3630ºF
– 5430ºF (2,000ºC – 3,000ºC)
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Crust
Mantle
Core
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
The Earth is made up of five main
physical layers.





lithosphere
asthenosphere
mesosphere
outer core
inner core
EARTH’S INTERIOR

The crust and the upper part of
the mantle are very similar, very
hard and rocky.

Lithosphere – the crust and the
uppermost part of the mantle
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Lithosphere
(rigid)
Crust
Mantle
Core
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
Material in the mantel is softer
and can bend, somewhat like
plastic.
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
Asthenosphere – the soft rock
layer of the Earth that can flow
slowly

The lithosphere floats on top of
the asthenosphere.

Enormous heat and pressure
allow this soft, solid rock to move.
EARTH’S INTERIOR
Lithosphere
(rigid)
Asthenosphere
(plastic)
Crust
Mantle
Core
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
Mesosphere– the hard rock layer
that makes up most of the mantle

Extreme pressure at this depth
makes the rock very hard and
unable to move like the
asthenosphere.
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Lithosphere
(rigid)
Asthenosphere
(plastic)
Crust
Mantle
Mesosphere
(rigid)
Core
EARTH’S INTERIOR

The core has two parts, an outer
core and inner core.

Outer core – a layer of molten,
liquid metal that surrounds the
inner core

Inner core – a dense ball of solid
metal
EARTH’S INTERIOR
Lithosphere
(rigid)
Asthenosphere
(plastic)
Crust
Mantle
Mesosphere
(rigid)
Outer Core
(liquid)
Inner Core
(solid)
Core
EARTH’S INTERIOR
Diagram From:
geophysics.ou.edu
EARTH’S INTERIOR
Diagram From:
faculty.weber.edu
EARTH’S INTERIOR
Diagram From:
spring.net
EARTH’S INTERIOR
Layers of the Earth
Depiction
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
Currents in the liquid outer core
force the solid inner core to spin
at a slightly faster rate than the
rest of the planet.

The currents created by the outer
core create the Earth’s magnetic
field.
EARTH’S INTERIOR

The Earth acts like a giant bar
magnet.

A compass will point to the
Earth’s magnetic North pole.
EARTH’S INTERIOR
Diagram From: glossary.oilfield.slb.com
EARTH’S INTERIOR
Diagram From: cnx.org