The Restless Earth

Question 1

Name the layers of Earth from the inner layer to the outer layer.

Answer 1

Inner core, outer core, mantle, crust.

Question 2

What is the mantle?

Answer 2

The layer around the core, which is semi-molten Rock that moves very slowly.

Question 3

The crust is divided into lots of slabs called ______. They _____ on the mantle.

Answer 3

The crust is divided into lots of slabs called tectonic plates.They float on the mantle.

Question 4

Plates are made up of two types of crust named what?

Answer 4

Continental (thicker and less dense),
and oceanic (thinner and more dense).

Question 5

Why do the plates move?

Answer 5

Because the rock in the mantle underneath them is moving.

Question 6

The places where plates meet are called what?

Answer 6

Boundaries or plate margins.

Question 7

Name the three types of plate margins.

Answer 7

Destructive , constructive and conservative.

Question 8

What’s a destructive margin?

Answer 8

Where two plates are moving towards each other.

Question 9

What happens when an oceanic plate meets a continental plate and they’re moving towards each other?

Answer 9

The oceanic plate is forced down into the mantle and destroyed. This can create volcanoes or ocean trenches.

Question 10

What is the earths core made out of?

Answer 10

Solid iron and nickel.

Question 11

What’s a constructive margin?

Answer 11

Where two plates are moving away from each other. Magma (molten rock) rises from the mantle to fill the gap and cools to create new crust.

Question 12

What’s a conservative margin?

Answer 12

Where two plates are moving sideways past each other, or moving in the same direction but at different speeds. Crust isn’t created or destroyed.

Question 13

How are fold mountains formed?

Answer 13

When plates collide the sedimentary rocks that have built up between them are folded and forced upwards to form mountains.

Question 14

What are fold mountains used for?

Answer 14

Farming , hydro-electric power, mining, forestry , tourism.

Question 15

What’s a composite volcano?

Answer 15

Made up of ash and lava that’s erupted, cooled and hardened into layers. The lava is usually thick and flows slowly. It hardens to form a steep-sided volcano.

Question 16

What’s a shield volcano?

Answer 16

Made up of only lava. The lava is runny, flows quickly and spreads over a wide area forming a low, flat volcano.

Question 17

What’s a dome volcano?

Answer 17

Made up of only lava. The lava is thick, flows slowly and hardens quickly, forming a steep-sides volcano.

Question 18

How can you predict a volcano and what changes happen?

Answer 18

Things like tiny earthquakes, escaping gas, and changes in the shape of the volcano (bulges in the land where magma has built up underneath) can all mean that an eruption is happening soon.

Question 19

Where do you find supervolcanoes?

Answer 19

They can be found in a handful of places around the world, at destructive plate margins or at very hot places over the mantle (hotspots).

Question 20

How are supervolcanoes formed?

Answer 20

Magma rises up through cracks in the crust to form a large magma basin below the surface. The pressure of the magma causes a circular bulge on the surface.

Question 21

How do supervolcanoes erupt?

Answer 21

The bulge cracks, creating vents for lava to escape through. The lava erupts out causing earthquakes.

Question 22

What happens after a supervolcano has erupted?

Answer 22

As the magma basin empties the bulge is no longer supported so it collapses causing more magma to spew out. It leaves a big crater behind called a caldera where the bulge collapsed.

Question 23

What will happen if a supervolcano erupts?

Answer 23

An eruption will throw out thousands of cubic kilometres of rock, ash and lava (much more than normal) , a cloud of superheated gas will flow at high speed burning everything, ash will block out almost all day light , and bury fields and buildings

Question 24

What causes an earthquake?

Answer 24

Earthquakes are caused by tension that builds when plates are stuck together and when they eventually become unstuck it causes shock waves (vibrations)

Question 25

What’s the focus and epicentre when talking about earthquakes?

Answer 25

The focus is where the waves are stronger and cause more damage, the epicentre is on the earths surface right above the focus.

Question 26

How do we measure earthquakes?

Answer 26

Using either the richter or mercalli scale.

Question 27

What is the Richter scale?

Answer 27

This measures the amount of energy released by an earthquake (called the magnitude).

Question 28

What’s the mercalli scale?

Answer 28

This measures the effect of an earthquake, it’s a scale of 1-12. Effects are measured by asking eyewitnesses of what happened. Observations can be in the form of words or photos.

Question 29

What’s a seismometer?

Answer 29

A machine with an “arm” which moves with the vibrations of the earth.

Question 30

What happens when an earthquake starts at sea?

Answer 30

It causes a tsunami.