Restless earth: volcanoes

Question 1

How do the tectonic plates move apart

Answer 1

Convection currents in the earths mantle rise, as the heat rises to the earths crust they then begin to cool down and sink down again in a continuous process. The plates can either move together or apart from the heat

Question 2

How far do the plate tectonics move each year

Answer 2

They float like rafts on mantle and are moved by convection currents very slowly about 5-20 cm a year

Question 3

What is the area where two plates meet called

Answer 3

The plate boundary, along these the crust is destroyed, torn apart and thrust up into mountain ranges

Question 4

What happens on the destructive plate margin

Answer 4

Denser oceanic crust is pushed towards continents by constructive plate movement.
As the oceanic crust is heavier it sinks underneath continental plates.
The oceanic plate melts as it sinks ,due to heat and pressure, magma rises up.

Question 5

What happens on the constructive plate margin

Answer 5

Plates move apart in the middle of oceans and magma rises from the mantle.
This constructs new ocean floor and forces oceanic plates to push against either side

Question 6

What happens on a conservative plate margin

Answer 6

Plates slide past each other in opposite directions.

Sometimes plates lock and pressure builds, leading to earthquakes

Question 7

What happens on a collision plate margin

Answer 7

Continental plates meet continental plates and push up and fold the land to form huge mountain ranges

Question 8

What does it mean when a volcano is dormant

Answer 8

Dormant is when it isn’t likely to erupt and is said to be sleeping

Question 9

What does it mean when a volcano is extinct

Answer 9

An extinct volcano is when it’s unlikely to erupt again or at all

Question 10

Where are you likely to see a volcano happen

Answer 10

Destructive plate margin ( violent eruptions)
Constructive plate margins ( gentle eruptions)
Hot spots

Question 11

What are the primary effects of a volcanic eruption

Answer 11

Ash fall
Pyroclastic flow
Lava flows

Question 12

What is ashfall

Answer 12

Tiny particles of cooled magma rain out of the sky

Question 13

What is pyroclastic flow

Answer 13

A fast flowing river of liquid rock, rock fragments and gases that flows down the side of a volcano

Question 14

What are lava flows

Answer 14

Red hot (800*c) melted rock. Can travel at running speed

Question 15

What are the secondary effects of a volcanic eruption

Answer 15

Global cooling- below average temperatures

Tsunami- destruction of hurling waves

Question 16

Reasons for living near a volcano

Answer 16

Cheaper cost of living
Nutrients from ash cloud fertilise soil
Volcanoes are a source of goethermal energy which can be used to generate electricity
Family in area

Question 17

How can you reduce impacts of hazards

Answer 17

Prediction
Education 
Aid
Building techniques
Planning

Question 18

What is sustainable development

Answer 18

Sustainable development is development that meets the needs of the present , without compromising the ability of future generations to meet their own needs

Question 19

What is a natural hazard

Answer 19

A natural hazard is a naturally occurring event that can potentially affect life or property