2.1 Earthquakes and Volcanoes

Question 1

Oceanic crust

Answer 1

Younger
Heavier (sinks)
Constantly being destroyed and replace

Question 2

Continental crust

Answer 2

Older
Lighter (cannot sink)
Permanent

Question 3

What is the general distribution of earthquakes and volcanoes?

Answer 3

Found near plate boundaries
Pacific ring of fire
Mid-Atlantic ridge

Question 4

Collision boundary

Answer 4

Two continental plates move towards each other.

e.g. Indo Australian and Eurasian plate

Question 5

Constructive boundary

Answer 5

Two plates moving away from each other.

e.g. North American and Eurasian plate (mid-Atlantic ridge)

Question 6

Conservative boundary

Answer 6

Two plates slide past each other.

North american plate and Pacific plate

Question 7

Destructive boundary

Answer 7

Oceanic plate is subducted by a continental plate.

Question 8

What do constructive boundaries cause?

Answer 8

Gentle earthquakes and volcanoes

No fold mountains

Question 9

What do destructive boundaries cause?

Answer 9

Violent earthquakes and volcanoes

Fold mountains

Question 10

What do collision boundaries cause?

Answer 10

Violent earthquakes
Fold mountains
No volcanoes

Question 11

What do conservative boundaries cause?

Answer 11

Violent earthquakes
No volcanoes
No fold mountains

Question 12

Earthquake

Answer 12

Series of vibrations or movements in the earth’s crust

Question 13

How is an earthquake caused?

Answer 13

Two plates get stuck; pressure builds up; one plate jerks forward sending shock waves.

Question 14

Focus

Answer 14

The point of origin of an earthquake

Question 15

Epicentre

Answer 15

The point on the earth’s surface vertically above the focus of an earthquake

Question 16

Seismic waves

Answer 16

Waves of energy that travel through the Earth’s layers

Question 17

Subduction zone

Answer 17

Where one plate goes under another (destructive margin)

Question 18

Effects of earthquakes (5)

Answer 18

Deaths
Water pipes burst
Water contamination - water borne diseases
Buildings destroyed 
Tsunami can follow

Question 19

Ways of predicting an earthquake (3)

Answer 19

Measure earth tremors
Find patterns in locations
Unusual animal behaviour

Question 20

Ways of preparing for an earthquake (5)

Answer 20

Build earthquake-proof buildings 
Training emergency services 
Setting up warning systems 
Evacuation plans
Practice drills

Question 21

Ways of making a building earthquake-proof (4)

Answer 21

Weights on roof to reduce movement
Rubber-shock absorbers in foundations
Foundations sunk deep into bedrock
Automatic shutters to protect from broken windows.

Question 22

Volcano

Answer 22

A vent in the earth’s surface were magma, gas or ash escapes.

Question 23

Explain how a volcano is created at a constructive margin

Answer 23

Plates move away from each other

Magma rises to fill the gap

Question 24

Explain how a volcano is created at a destrutcive margin

Answer 24

Subducted oceanic plate melts due to heat from mantle

New, hot magma is less dense and rises to the surface.

Question 25

Active volcano

Answer 25

Has erupted recently

Question 26

Dormant volcano

Answer 26

Hasn’t erupted recently but may in future

Question 27

Extinct

Answer 27

Unlikely to ever erupt (no magma inside)

Question 28

Shield volcano (4)

Answer 28

Gentle slopes
Slow flowing lava but frequent eruptions
Made from solidified lava
Constructive boundaries

Question 29

Cone volcano (2)

Answer 29

Steep slopes

Violent eruption

Question 30

Composite volcano / stratovolcano (5)

Answer 30

Mix of cone and shield volcanoes 
Eruptions vary in strength
Made of layers of ash and lava
Destructive boundaries 
Pyroclastic flow

Question 31

Advantages a volcano brings (3)

Answer 31

Tourism
Fertile soil
Geothermal energy

Question 32

Disadvantages a volcano brings (3)

Answer 32

Destruction of land/homes/transport/jobs
Poisonous gases (SO2)
Pyroclastic flow

Question 33

How can we predict a volcano (4)

Answer 33

Tremors within the volcano
Ground temperatures rise
Volcano emits gas and steam
Animal behaviour

Question 34

How can we prepare for a volcano (4)

Answer 34

Warning systems
Evacuation plan
Better trained emergency services
Emergency food supply

Question 35

Pyroclastic flow

Answer 35

Mixture of hot steam, ash, rock and dust

Question 36

Crater

Answer 36

Bowl-shaped geological formation at the top of the volcano

Question 37

Vent

Answer 37

Opening exposed on the earth’s surface where volcanic material is emitted

Question 38

Magma chamber

Answer 38

Reservoir of magma within the earth’s crust beneath a volcano.

Question 39

Seismograph

Answer 39

Instrument that measures and records force and duration of earthquake

Question 40

Tectonic plates

Answer 40

Rigid pieces of the earth’s lithosphere which together make the earth crust