Tectonic plate map

The Earth's crust and upper mantle are broken into pieces called tectonic plates. This map shows the major tectonic plates. The plates are constantly moving.

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

In this activity, you will investigate the boundaries between them. You'll see how energy released by the separation,
collision or sliding of plates affects the Earth's surface.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

South

American

plate

African

plate

Magnifier

The highlighted location on the map is in the middle of the Atlantic Ocean.

This is where the African and South American tectonic plates meet.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

South

American

plate

African

plate

Magnifier

Select this location for a closer view, and to head back in time 100 million years.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust
Tectonic viewer
0

Movement:

km

Timeline

0

50

100

0.0
million years

Let's investigate what type of plate movement is occurring at this location.

Try each of the Tectonic forces, selecting Apply force to see which one creates movement between the African and South American plates.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust
Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

50

100

30.0
million years
Back

That's right.

You have found the tectonic force pair occurring at this plate boundary.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust
Tectonic viewer
900

Movement:

km

The boundary between these two plates is called a divergent boundary, because the plates are moving apart. They will probably continue to do so for millions of years into the future.

Now select years in the Timeline and move the slider to work out approximately how far apart the plates are moving each year.

In one year, they move apart:

3 centimetres

12 centimetres

3 kilometres

Check
Timeline

0

50

100

0

100

200

Back

Correct.

These plates are moving apart at about 3 centimetres per year. This may not seem like much, but let's see what it means if we switch the time scale to millions of years.

OK

That's not right.

Set the slider on the Timeline to ten years and look at the Movement counter to work out the answer.

Try again

That's still not right.

The plates at this boundary
move apart at about
3 centimetres per year.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust
Tectonic viewer
0

Movement:

km

Now the Timeline is set to million years. Select Apply force or move the slider to 20 million years and watch what happens as the plates move apart.

How would you describe what happened?

The plates did not move.

As the plates moved apart, the
gap between them was filled.

The plates moved apart and
then came back together.

Check
Timeline

0

50

100

0.0
million years
Back

Correct.

As the plates pulled apart, magma (molten rock from the mantle) rose up to fill the gap.

OK

That's not right.

Move the slider again and watch carefully to see what happens to the plates.

Try again

That's not right.

The plates moved apart, but
they did not move back
together.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust A B C
Tectonic viewer
600

Movement:

km

This time, move the Timeline slider to 80 million years.

Where do you think the magma that rose up to fill the gap at
20 million years is located now?

Select A, B or C on the diagram.

Timeline

0

50

100

20.0
million years
Back

Correct.

The magma cools and solidifies, becoming part of the oceanic crust. As the plates move, the solidified magma moves as well, away from the plate boundary.

OK

That's not right.

Move the slider again and watch carefully to see what happens to the magma between 20 and 80 million years.

Try again

That's still not right.

The correct answer is B.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Ocean floor
Tectonic plate Mantle Oceanic crust
Tectonic viewer
2400

Movement:

km

Timeline

0

50

100

80.0
million years
Back

Correct.

The oceanic crust is highest near the gap between the plates.

OK

That's not right.

Look closely at the oceanic crust in the diagram.

Try again

That's still not right.

Move the Timeline slider and look at the sea floor near the gap.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Tectonic viewer
2400

Movement:

km

Timeline

0

50

100

80.0
million years
Back

Correct.

The plates 'float' on the Earth's mantle, which is composed of super-heated rocky material that moves as if it is flowing very slowly. Newly formed rocks, which are very hot, are less dense and more buoyant.

As the rocks gradually move away from the plate boundary and cool off, they become denser and sink lower in the mantle. The older they get, the denser they become.

OK

That's not right.

Rising magma does affect the slope of the sea floor.

Try again

That's not right.

Here's a hint: most substances tend to be less dense when they are hot.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Tectonic viewer
0

Movement:

km

Move the slider to 100 million years and watch the animation.

As the plates move apart over millions of years, what do you think is happening?

A submerged mountain range is forming.

The sea floor is spreading,
making the ocean wider.

Both of the above

Check
Timeline

0

50

100

0.0
million years
Back

Correct.

As the plates move apart, the sea floor
spreads, widening the ocean about
3 centimetres per year, or about 30 kilometres
per million years. Over 130 million years, this
process split what was a single continent into
Africa and South America, and created the
vast Atlantic Ocean between them.

Sea-floor spreading at this plate boundary has
also created a submerged mountain range
known as the Mid-Atlantic Ridge. Some of this
range rises above sea level as islands.

130 million years ago

OK

That's partly right, but it is not the full answer.

Try again

That's still only partly right.

As the plates move apart, this creates both a submerged mountain range and makes the ocean wider.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

African

plate

Oceanic crust South American plate Mantle Oceanic crust African plate A B C
Tectonic viewer
3000

Movement:

km

Look at the diagram. The rocks are labelled in three locations:
A, B and C.

In which order were the rocks created, from first to last?

A, B, C

C, B, A

B, A, C

Check
Timeline

0

50

100

100.0
million years
Back

Correct.

The rocks at position A are the youngest and those at C are the oldest.

Geologists have dated the rocks and found that the further away from the plate boundary, the older the rocks.

This is one piece of evidence to support the theory of sea-floor spreading.

OK

That's not right.

Have another look at the diagram.

Try again

That's still not right.

Think about how the rocks are being formed at this boundary to help you decide which of the ridges was created first.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Eurasian

plate

Now we've moved to another location: Iceland.

Like the previous location, this island also lies on the Mid-Atlantic Ridge. However, Iceland is in the North Atlantic Ocean.

North American plate Mid-Atlantic
Ridge
Atlantic Ocean Iceland Eurasian plate Volcanoes Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Eurasian

plate

In Iceland, we have the rare opportunity to see the effects of a divergent boundary on land.

What do you think the effects of plate movement are in this location?

Cracks in the ground

Volcanoes

Both of the above

Check
North American plate Mid-Atlantic
Ridge
Atlantic Ocean Iceland Eurasian plate Volcanoes Back

Correct.

As the plates spread apart at this location, cracks in the ground form. These are called fissure vents.

They can erupt, discharging lava explosively or non-explosively, and forming large volcanoes.

Acknowledgements OK
<

That's only partly right.

Look at the diagram again.

Try again

That's only partly correct.

Try again

Acknowledgements

Please refer to Conditions of use.

The illustration of a fissure eruption at Krafla in Iceland by David Hardy has been reproduced by kind permission of David Hardy/Science Photo Library.

X

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Eurasian

plate

If the divergent boundary runs roughly through the middle of Iceland, where would you find the oldest rocks?

Near the centre of the island

On the east coast only

On both the east and west
coasts

Check
North American plate Mid-Atlantic
Ridge
Atlantic Ocean Iceland Eurasian plate Volcanoes Back

Correct.

The oldest rocks would be furthest from the plate boundary, so they would be near the east and west coasts.

OK

That's not right.

Look at the diagram. Remember that the new rock forms at the plate boundary.

Try again

That's not right.

Remember, there are two plates moving in opposite directions away from the boundary.

Try again

Acknowledgements

Please refer to Conditions of use.

The illustration of a fissure eruption at Krafla in Iceland by David Hardy has been reproduced by kind permission of David Hardy/Science Photo Library/Photolibrary.com.

X

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Eurasian

plate

Congratulations! You have completed this activity.

You have explored how tectonic plates at divergent boundaries move away from each other. This process has formed submerged mountain chains and helped create oceans through sea-floor spreading.

When you're ready, select another activity from the top of the screen.

North American plate Mid-Atlantic
Ridge
Atlantic Ocean Iceland Eurasian plate Volcanoes Back
Tectonic plate map

South

American

plate

Nazca

plate

Magnifier

The location highlighted on the map is on the west coast of South America.

Here, there is a plate boundary where continental crust meets oceanic crust.

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

South

American

plate

Nazca

plate

Magnifier

Select this location for a closer view and to go back in time 100 million years.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Tectonic viewer
0

Movement:

km

Timeline

0

25

50

0.0
million years

Let's investigate what type of plate movement is occurring at this location.

Try each of the Tectonic forces, selecting Apply force to see which one creates movement between the Nazca plate and the South American plate.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

25

50

0.0
million years
Back

That's right.

You have found the tectonic force pair occurring at this plate boundary.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Tectonic viewer
0

Movement:

km

The boundary between these two plates is called a convergent boundary, because the two plates are moving towards one another.

Now select years in the Timeline and move the slider to work out approximately how much the plates move each year.

Timeline
0.0

0

25

50

0

100

200

Back

Correct.

These plates are moving towards each other at a rate of about
8 centimetres per year.

OK

That's not right.

Set the slider on the Timeline to ten years and look at the Movement counter to work out the answer.

Try again

That's still not right.

The plates at this boundary
move about 8 centimetres per year.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Oceanic crust Continental crust
Tectonic viewer
0

Movement:

km

What do you think will happen if the plates continue to move towards each other over millions of years?

The plates will eventually stop moving.

The oceanic crust will slide
over the continental crust.

The oceanic crust will slide
under the continental crust.

Check
Timeline

0

25

50

0.0
million years
Back

Correct.

The oceanic crust is denser than the lighter continental crust, so it will slide under it.

This process is called
subduction.

OK

That's not right.

Select Apply force again and watch closely what happens to the plates.

Try again

That's still not right.

The oceanic crust will slide
under the continental crust.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Oceanic crust Continental crust
Tectonic viewer
0

Movement:

cm

Let's look at subduction in action.

Set the Timeline to million years. Then select Apply force or move the slider to watch the plates move over 10 million years.

Timeline

0

100

200

0

25

50

0
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
800

Movement:

km

Can you see that the oceanic crust continues to subduct under the continental crust?

What is happening to the oceanic crust?

It is forced down into the hot mantle, where it melts.

It is forced down into the
mantle, but does not change.

It buckles.

Check
Timeline

0

25

50

10.0
million years
Back

Correct.

The oceanic crust is forced deeper into the Earth's mantle, where the temperatures are so high that rock melts. In this way, the crust is 'recycled'.

OK

That's not right.

Use the Timeline slider to watch the plates move and see what happens.

Try again

That's still not right.

Look at the animation to see what happens to the oceanic crust.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
800

Movement:

km

Now move the slider to 15 million years and see what happens to the oceanic crust.

Timeline

0

25

50

10.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
1200

Movement:

km

As the oceanic crust melts, it is recycled in the Earth's mantle.

But some of the molten rock rises up through the continental crust under extreme temperature and pressure. What do you think will happen to this molten rock?

Some of it will break through
the continental crust to create volcanoes.

It will all become solid before
it reaches the surface.

The molten rock will melt the existing mountain range.

Check
Timeline

0

25

50

15.0
million years
Back

Correct.

It will break through the continental crust to create volcanoes. It also deforms and lifts the continental crust.

Let's see it in action.

OK

This can happen, but it is not happening in this case.

Try again

That's not right.

The rising molten rock does not melt the existing mountain range.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
1200

Movement:

km

Select Apply force and watch what happens.

Timeline

0

25

50

15.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
4000

Movement:

km

Volcanoes can form when heavy oceanic crust subducts under lighter continental crust.

Which other geological events do you think could result from subduction?

Tsunamis

Earthquakes

Both of the above

Check
Timeline

0

25

50

50.0
million years
Back

Correct.

The surface of the subducting plate grinds against the other plate. Sections of its crust can become locked and then suddenly release, producing earthquakes.

In this location, most of the earthquakes occur deep under the continent. However, some occur at shallow depths
offshore, which can create a tsunami.

Offshore earthquakes have generated numerous tsunamis in this region over the past few centuries.

OK

That's partly right.

Have another go.

Try again

That's still only partly right.

Both tsunamis and earthquakes could result from this type of plate movement.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

South

American

plate

Nazca

plate

Nazca plate Oceanic crust Mantle Continental crust South American plate
Tectonic viewer
4000

Movement:

km

This diagram represents the geological situation today in South America.

Where the Nazca plate subducts under the South American plate, it creates a deep sea trench all along the coast.

Over millions of years, the converging plates have formed the Andes, the longest mountain range in the world.

Timeline

0

25

50

50.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Eurasian

plate

Indian

plate

Magnifier

Now let's move to a location in northern India.

There is a boundary between the Indian plate and the Eurasian plate at the highlighted spot on the map.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Eurasian

plate

Indian

plate

Magnifier

Select this location for a closer view and to go back in time 40 million years.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian plate

Indian

plate

Tectonic viewer
0

Movement:

km

Timeline

0

25

50

0.0
million years

Let's investigate what type of plate movement is occurring at this location.

Try each of the Tectonic forces, selecting Apply force to see which one is creating movement here.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian plate

Indian

plate

Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

25

50

10.0
million years
Back

That's right.

You have found the tectonic force pair occurring at this plate boundary.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian plate

Indian

plate

Tectonic viewer
800

Movement:

km

Timeline

0

25

50

10.0
million years

This is a convergent boundary between two continental crusts.

What do you think will happen if this force is applied over millions of years?

Try it and see. The Timeline is set to million years. Use the slider to move the plates over 40 million years.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian plate

Indian

plate

Tectonic viewer
3200

Movement:

km

Timeline

0

25

50

40.0
million years

Because the two continental crusts are of similar density, one doesn't slide under the other.

They crash into each other and deform.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian plate

Indian

plate

Indian plate Continental crust Eurasian plate Continental crust
Tectonic viewer
3200

Movement:

km

What sort of geographical feature do you think this process would create?

Mountains

Volcanoes

Islands

Check
Timeline

0

25

50

40.0
million years
Back

Correct.

The largest mountain range in the world, the Himalayas, is the result of the Indian plate colliding with the Eurasian plate at this boundary.

The Himalayas are still being pushed upwards today.

OK

That's not right.

The force of the plates crashing into each other pushes the land upwards. There is no magma rising to create volcanoes.

Try again

That's not right.

This boundary is under a continent, not under water, so islands would not be created.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Australian

plate

Pacific

plate

Magnifier

Now let's move to a location in the South Pacific. There is a boundary between the oceanic crusts of the Pacific plate and the Australian plate at the highlighted spot on the map.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Australian

plate

Pacific

plate

Magnifier

Select this location for a closer view and to go back in time 50 million years.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Pacific plate

Australian plate

Australian plate Oceanic crust Pacific plate Oceanic crust
Tectonic viewer
0

Movement:

km

This is a convergent boundary.
The cross section you see is a view to the north.

What is happening at the
boundary?

The plates have stopped
moving.

The Australian plate is
subducting under the Pacific
plate.

The Pacific plate is subducting
under the Australian plate.

Check
Timeline

0

25

50

0.0
million years
Back

Correct.

The Pacific plate subducts under the Australian plate.

OK

That's not right.

Look at the diagram again.

Try again

That's still not right.

The Pacific plate subducts under the Australian plate.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Pacific plate

Australian plate

Australian plate Oceanic crust Pacific plate Oceanic crust
Tectonic viewer
0

Movement:

km

From what you've seen in other examples of convergent boundaries, what do you think could happen as the Pacific plate subducts under the Australian plate?

Select Apply force to try it and see.

Timeline

0

25

50

0.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Pacific plate

Australian plate

Australian plate Oceanic crust Pacific plate Oceanic crust
Tectonic viewer
4000

Movement:

km

Did you notice what happened? The Pacific plate melts as it is forced deeper into the Earth's mantle.

Some of the molten rock rises through the Australian plate under extreme temperature and pressure to create the Tonga-Kermadec Arc, which is a chain of volcanic islands.

Where the two plates meet, they form an 8-kilometre-deep underwater trench: the Tonga-Kermadec Trench.

Timeline

0

25

50

50.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Pacific plate

Australian plate

Australian plate Oceanic crust Pacific plate Oceanic crust
Tectonic viewer
4000

Movement:

km

Given that subduction is happening at this boundary, what other sort of geological activity is likely?

Tsunamis

Earthquakes

Both tsunamis and earthquakes

Check
Timeline

0

25

50

50.0
million years
Back

Correct.

Earthquakes can occur at subduction zones because the converging crusts sometimes lock for a time, then move suddenly to release the stress. Some of the world's biggest earthquakes have been at subduction zones.

If the earthquake is shallow and occurs offshore, it can cause a tsunami.

OK

That's partly right. Have another go.

Try again

That's still only partly right.

It's likely that both tsunamis and earthquakes may occur.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Pacific plate

Australian plate

Australian plate Oceanic crust Pacific plate Oceanic crust
Tectonic viewer
4000

Movement:

km

Congratulations! You have completed this activity.

You have explored several different convergent boundaries. When tectonic plates collide, this can form volcanoes, mountain chains and deep sea trenches. The force of the plates colliding can create earthquakes, and if this occurs offshore, tsunamis.

When you're ready, select another activity from the top of the screen.

Timeline

0

25

50

50.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

North

American

plate

Pacific

plate

Magnifier

Let's focus on the west coast of the United States. There is a boundary between the oceanic crust of the Pacific plate and the continental crust of the North American plate here.

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

North

American

plate

Pacific

plate

Magnifier

Select this location for a closer view and to go back in time to 1827.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

Let's investigate what type of plate movement is occurring at this location.

Try each of the Tectonic forces, selecting Apply force to see which one creates movement at this plate boundary.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

100

200

0
years
Back

That's right.

You have found the tectonic force pair occurring at this plate boundary.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

The boundary between these two plates is called a transform boundary. The tectonic forces here cause the two plates to slide past each other.

Now move the slider on the Timeline to work out approximately how much the plates move each year.

50 centimetres

0.5 centimetres

5 centimetres

Check
Timeline

0

100

200

0
years
Back

Correct.

The plates are grinding horizontally past each other at a rate of about 5 centimetres per year.

OK

That's not right.

Set the slider on the Timeline to ten years and look at the Movement counter to work out the answer.

Try again

That's still not right.

The plates are moving at a rate of about 5 centimetres per year.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

What do you think will happen if the plates continue to move past each other for 30 years?

Select Apply force to try it and see.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Continental crust Pacific plate Continental crust North American plate
Tectonic viewer
150

Movement:

cm

What happened?

The Pacific plate and the North American plate:

You can select Apply force to see this again if you want.

Moved further apart from each other

Gradually slid along their boundary, but the crust got
stuck and then released with a sudden jolt

Stayed still and then suddenly burst past each other

Check
Timeline

0

100

200

30
years
Back

Correct.

As we have seen, the plates continuously creep past each other at a rate of about
5 centimetres per year.

Over a period of time, a section of plate can get stuck, building up stress until it suddenly lurches free.

OK

That's not right.

Watch the animation again. Do the plates move away from each other, or slide past each other?

Try again

That's not right.

Watch the animation again. The plates continuously slide past each other, but some of the
crust gets stuck.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Continental crust Pacific plate Continental crust North American plate
Tectonic viewer
150

Movement:

cm

After 30 years of movement, there was a sound.

What do you think that sound represented?

An earthquake

A thunderstorm

An erupting volcano

Check
Timeline

0

100

200

30
years
Back

Correct.

It was the sound of an earthquake. As the plates slowly grind past each other, friction can stop a section of the crust from moving. Stress builds up in this 'locked' section until it suddenly releases in a huge jolt. The result is a major
earthquake.

While some sections of a boundary may lock, other sections may slide more freely, and large earthquakes do not occur there.

OK

That's not right.

Watch the animation again and imagine the force and vibrations caused by a section of the Earth's crust suddenly lurching or breaking.

Try again

That's not right.

Watch the animation again. This type of plate boundary doesn't involve magma (hot rock from the mantle) rising to the Earth's surface to form a volcano.

Try again

Are you sure you want to
go to another activity?

Yes No

The plate boundary we have been investigating is the San Andreas Fault in California. It is one of the most famous transform boundaries.

The photo shows a fence built over the San Andreas Fault. The gap in the fence happened during an earthquake. It shows how much this section of the plates moved during the sudden jolt.

Acknowledgements
Back

Acknowledgements

Please refer to Conditions of use.

The photograph of a fence offset by the San Andreas Fault during the earthquake in San Francisco, California, 18 April 1906 by Grove K Gilbert has been reproduced by kind permission of the National Information Service for Earthquake Engineering, University of California, Berkeley, USA.

Close

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
150

Movement:

cm

The earthquake we've explored happened in southern California in 1857. It was one of the largest earthquakes ever recorded in the United States. It left a
350-kilometre scar across the surface of the Earth. The shaking lasted at least a minute, and in some places the land slipped up to 9 metres.

Note the years on the Timeline, then select Apply force to see how long it takes before another earthquake occurs.

The next earthquake occurs after:

24 years

49 years

72 years

Check
Timeline

0

100

200

30
years
Back

Correct.

Although many small tremors occur every year, the next large earthquake on the San Andreas Fault happened 49 years later.

This was the devastating earthquake that occurred in northern California in 1906. Over 80% of the city of San Francisco was destroyed by the violent shaking and fires it caused.

OK

That's not right.

Use the slider on the Timeline
to work out the number of years between these two major earthquakes.

Try again

That's still not right.

It took 49 years before the next major earthquake occurred.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Tectonic viewer
395

Movement:

cm

Note the years on the Timeline and then select Apply force to see how long it takes before another large earthquake on the San Andreas fault occurs.

How long does it take for the next earthquake to occur?

38 years

52 years

83 years

Check
Timeline

0

100

200

79
years
Back

Correct.

Another destructive earthquake took place in northern California 83 years later, in 1989.

It caused extensive damage to buildings and freeways, and part of the San Francisco Bay Bridge collapsed.

OK

That's not right.

Use the slider on the Timeline to work out the number of years between this major earthquake and the previous one.

Try again

That's still not right.

It took 83 years before the next major earthquake occurred.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Pacific

plate

Continental crust Pacific plate Continental crust North American plate
Tectonic viewer
810

Movement:

cm

Given that there were 49 years between the 1857 and 1906 earthquakes, and then 83 years until the 1989 earthquake, how long do you think it will be before the next major earthquake occurs on the San Andreas Fault?

49 years

83 years

It is not possible to know.

Check
Timeline

0

100

200

162
years
Back

Correct.

It is very difficult to predict exactly when the next big earthquake will occur.

Although the movement of the plates is relatively constant, it is not known when the stress building up in different sections will be released, causing another large earthquake.

Based on the frequency of smaller tremors and other observations, geologists think it may happen before 2032, but no-one really knows.

OK

That's not right.

Have the other earthquakes occurred at exactly the same time intervals?

Try again

That's still not right.

It is not possible to know when the next earthquake will occur.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Juan

de Fuca

plate

Pacific

plate

Magnifier

Now let's move to a location in the Pacific Ocean.

There is a boundary between the Juan de Fuca plate and the Pacific plate at the highlighted spot on the map.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

Juan

de Fuca

plate

Pacific

plate

Magnifier

Select this location for a closer view.

Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

cm

Let's investigate what type of plate movement is occurring at this location.

Try each of the Tectonic forces, selecting Apply force to see which one creates movement at this plate boundary.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

cm

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

100

200

0
years
Back

That's right.

You have found the tectonic force pair occurring at this plate boundary.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

cm

This is also a transform boundary, where two plates slide past each other. However, this one is in the ocean.

Transform boundaries on the ocean floor are much more common than those on land.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

cm

Now select Apply force to see what happens as the plates move over 50 years.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
250

Movement:

cm

Did you notice that this transform boundary behaves in a very similar way to the one on land?

How would you describe what happened?

The plates moved past each
other smoothly.

The movement of the crust was blocked in one section, and
then it suddenly jolted free.

The plates didn't move at all.

Check
Timeline

0

100

200

50
years
Back

Correct.

Just like on land, friction stopped a section of the plates from moving for a period of time.

Eventually the tectonic stresses built up to a point where they overcame the friction and the crust jerked free suddenly.

This caused an earthquake, only this time it was underwater.

OK

That's not right.

Select Apply force again and watch what happens closely.

Try again

That's still not right.

The movement of the plates was blocked in one section, and then it suddenly jolted free.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Oceanic crust Pacific plate Oceanic crust Juan de Fuca plate
Tectonic viewer
250

Movement:

cm

Timeline

0

100

200

50
years
Back

Correct.

Tsunamis are not generated by earthquakes at transform boundaries, because the plates slide horizontally. Most tsunamis occur at subduction boundaries, where a section of the sea floor slips up or down.

In the 2004 tsunami in South-
East Asia, scientists estimate
that the sea floor may have
slipped up to 10 metres.

OK

That's not right.

Tsunamis can be generated at any distance from shore.

Try again

That's not right.

For a tsunami to form, the sea floor must suddenly move up or down.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Oceanic crust Pacific plate Oceanic crust Juan de Fuca plate
Tectonic viewer
250

Movement:

cm

Congratulations! You have completed this activity.

You have explored the dramatic effects of transform boundaries. When tectonic plates grind past each other, this can cause earthquakes on land or under the sea.

When you're ready, select another activity from the top of the screen.

Timeline

0

100

200

50
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map

This is a map showing the Earth's major tectonic plates.

Select a location to investigate what sort of tectonic activity is occurring there.

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

km

This is the Juan de Fuca Ridge, an underwater boundary between the oceanic crusts of the Juan de Fuca plate and the Pacific plate.

Your job is to investigate what is happening at this tectonic boundary.

Try each of the Tectonic forces, selecting Apply force to see which one is creating movement here.

Timeline

0

50

100

0.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

50

100

0.0
million years
Back

That's correct.

You have found that, at this boundary, the tectonic plates
are moving away from each other.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Now select the correct term in each drop-down menu to describe the tectonic activity at this location.

This is a   boundary between two tectonic plates carrying

crust.

Check
Back

Well done.

This location is a divergent boundary between two oceanic crusts.

OK

That's not right.

Check that both your answers
are correct.

Try again

That's not right.

Go back to the animation and see if you can recognise the type of tectonic activity found at this location.

Try again

That's still not right.

This location is a divergent boundary between two oceanic crusts.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Juan de Fuca

plate

Pacific plate

Now look at the list of geological features and events.

Select the ones that you think are most likely to occur at this location, then select Check.

This is a   boundary between two tectonic plates carrying

crust.

Back

Correct.

The Juan de Fuca Ridge is a divergent boundary under the Pacific Ocean.

As the ocean floor spreads, new crust is being created, as well as a submarine mountain chain about 500 kilometres long.

OK

The geological feature you have selected is incorrect.

Try again

The geological feature you have selected is incorrect.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

None of the geological features you have selected are correct.

Try again

None of the geological features you have selected are correct.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

At least one of the geological features you have selected is incorrect.

Try again

At least one of the geological features you have selected is incorrect. Read them carefully and try again.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

At least one of the geological features you have selected is incorrect.

Let's take a look at the correct answers.

OK

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

Try again

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You haven't selected all the correct geological features.

Let's take a look at all the correct answers.

OK

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Australian

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

This is the boundary between the Australian plate and the Pacific plate, on the South Island of New Zealand.

Your job is to investigate what is happening at this tectonic boundary.

Try each of the Tectonic forces, selecting Apply force to see which one is creating movement here.

Timeline

0

100

200

0
years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Australian

plate

Pacific

plate

Tectonic viewer
0

Movement:

cm

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

100

200

0
years
Back

That's correct.

You have found that, at this boundary, the tectonic plates
are sliding past each other.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Australian

plate

Pacific

plate

Now select the correct term in each drop-down menu to describe the tectonic activity at this location.

This is a   boundary between two tectonic plates carrying

crust.

Check
Back

Well done.

This location is essentially a transform boundary between
two sections of continental crust. However, there is some convergence happening at the same time.

OK

That's not right.

Check that both your answers
are correct.

Try again

That's not right.

Go back to the animation and
see if you can recognise the type
of tectonic activity found at this location.

Try again

That's still not right.

This location is a transform boundary between two continental crusts.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Australian

plate

Pacific

plate

The Alpine Fault is mainly a transform boundary, but there is some convergence as well.

Now look at the list of geological features and events.

Select the ones that you think are most likely to occur at this location, then select Check.

This is a   boundary between two tectonic plates carrying

crust.

Back

Correct.

This is the Alpine Fault in New Zealand, a boundary where the Pacific plate and the Australian plate are moving past and slightly toward each other at the same time.

The fault has ruptured at least four times in the past 900 years, causing major earthquakes. Each rupture also causes the Southern Alps to rise. Over about 140 million years, they have risen a total of 20 000 metres. The alps are however much lower than that, due to erosion.

OK

The geological feature you have selected is incorrect.

Try again

The geological feature you have selected is incorrect.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

None of the geological features you have selected are correct.

Try again

None of the geological features you have selected are correct.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

At least one of the geological features you have selected is incorrect.

Try again

At least one of the geological features you have selected is incorrect. Read them carefully and try again.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

At least one of the geological features you have selected is incorrect.

Let's take a look at the correct answers.

OK

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

Try again

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

You can select any activity at
the top of the screen to review information about tectonic plates.

Try again

You haven't selected all the correct geological features.

Let's take a look at all the correct answers.

OK

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Juan de

Fuca plate

Tectonic viewer
0

Movement:

km

This is the boundary between the Juan de Fuca plate and the North American plate.

Your job is to investigate what is happening at this tectonic boundary.

Try each of the Tectonic forces, selecting Apply force to see which one is creating movement here.

Timeline

0

50

100

0.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Juan de

Fuca plate

Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

50

100

0.0
million years
Back

That's correct.

You have found that, at this boundary, the Juan de Fuca
plate and the North American
plate are moving towards each
other.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Juan de

Fuca plate

Now select the correct term in each drop-down menu to describe the tectonic activity at this location.

This is a   boundary between two tectonic plates carrying

crust.

Check
Back

Correct.

This location is a convergent boundary between oceanic and continental crusts.

OK

That's not right.

Check that both your answers
are correct.

Try again

That's not right.

Go back to the animation and
see if you can recognise the type
of tectonic activity found at this location.

Try again

That's still not right.

This location is a convergent boundary between oceanic and continental crusts.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

North

American

plate

Juan de

Fuca plate

Now look at the list of geological features and events.

Select the ones that you think are most likely to occur at this location, then select Check.

This is a   boundary between two tectonic plates carrying

crust.

Back

Correct.

These are all real or possible results of the Juan de Fuca plate subducting under the North American plate.

At this boundary, subduction has created a chain of volcanoes on the west coast of North America called the Cascade Arc, of which Mount St Helens is the most active.

OK

The geological feature you have selected is incorrect.

Try again

The geological feature you have selected is incorrect.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

None of the geological features you have selected are correct.

Try again

None of the geological features you have selected are correct.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

At least one of the geological features you have selected is incorrect.

Try again

At least one of the geological features you have selected is incorrect. Read them carefully and try again.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

At least one of the geological features you have selected is incorrect.

Let's take a look at the correct answers.

OK

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

Try again

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

You can select any activity at
the top of the screen to review information about tectonic plates.

Try again

You haven't selected all the correct geological features.

Let's take a look at all the correct answers.

OK

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian

plate

Australian

plate

Tectonic viewer
0

Movement:

km

This is the underwater boundary between the Eurasian plate and the Australian plate.

Your job is to investigate what is happening at this tectonic boundary.

Try each of the Tectonic forces, selecting Apply force to see which one is creating movement here.

Timeline

0

50

100

0.0
million years
Back

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian

plate

Australian

plate

Tectonic viewer
0

Movement:

km

Great start!

Now that you've tried each of the force pairs, which type of boundary do you think occurs at this location?

Transform boundary Divergent boundary Convergent boundary Check
Timeline

0

50

100

0.0
million years
Back

That's correct.

You have found that, at this boundary, the Australian plate and the Eurasian plate are moving towards each other.

OK

There doesn't appear to be any movement caused by this force pair. Please try another force.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian

plate

Australian

plate

Now select the correct term in each drop-down menu to describe the tectonic activity at this location.

This is a   boundary between two tectonic plates carrying

crust.

Check
Back

Correct.

There is a convergent boundary between the oceanic crusts of these two tectonic plates.

OK

That's not right.

Check that both your answers
are correct.

Try again

That's not right.

Go back to the animation and
see if you can recognise the type
of tectonic activity found at this location.

Try again

That's still not right.

This location is a convergent boundary between two oceanic crusts.

Try again

Are you sure you want to
go to another activity?

Yes No
Tectonic plate map
Tectonic plates

Eurasian

plate

Australian

plate

Look at the list of geological features and events.

Select the ones that you think are most likely to occur at this location, then select Check.

This is a   boundary between two tectonic plates carrying

crust.

Back

Correct.

The Australian plate is subducting under a part of the Eurasian plate called the Sunda subplate, forming a sea trench that is 2600 kilometres long. It has also created a 3000-kilometre chain of volcanoes in Indonesia.

Tectonic movement along this boundary was responsible for the 2004 South-East Asian tsunami and the 2005 Sumatra earthquake.

OK

The geological feature you have selected is incorrect.

Try again

The geological feature you have selected is incorrect.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

None of the geological features you have selected are correct.

Try again

None of the geological features you have selected are correct.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

You have not selected any of the correct geological features.

Let's take a look at the correct answers.

OK

At least one of the geological features you have selected is incorrect.

Try again

At least one of the geological features you have selected is incorrect. Read them carefully and try again.

You can select any activity at the top of the screen to review information about tectonic plates.

Try again

At least one of the geological features you have selected is incorrect.

Let's take a look at the correct answers.

OK

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

Try again

You have not selected all the correct geological features.

Read them again carefully and see if you can find the rest.

You can select any activity at
the top of the screen to review information about tectonic plates.

Try again

You haven't selected all the correct geological features.

Let's take a look at all the correct answers.

OK

Are you sure you want to
go to another activity?

Yes No

Congratulations! You have completed this activity.

You have successfully investigated four of the many locations around the world where the movement of tectonic plates is shaping our physical world.

When you're ready, select another activity from the top of the screen.

Congratulations! You have completed this activity.

You have successfully investigated four of the many locations around the world where the movement of tectonic plates is shaping our physical world.

You have now completed all of the Tectonic boundaries activities. You can go back and review any of your completed activities, or start again.

Back Restart

Are you sure you want to
go to another activity?

Yes No