Unit 1 - Restless Earth

Question 1

Describe the differences between oceanic and continental crusts

Answer 1

OCEANIC -
•Under the ocean
•Thin but dense
•Made from basalt

CONTINENTAL -
•Under land
•Thick but less dense
•Made of granite

Question 2

Describe the layers of the earth

Answer 2

Crust - 0-50km thick

Mantle - 3000km thick, semi solid consistency (custardy)

Outer Core - 2300km thick, iron/nickel liquid consistency

Inner Core - 1200km thick, iron/nickel, solid consistency

Question 3

Describe how convection currents move tectonic plates

Answer 3

The mantle is warmed by the core

The mantle rises to the earth’s surface

The movement of the magma in the mantle pulls the tectonic plates

The molten rock cools and sinks back towards the core

Question 4

What is the lithosphere?

Answer 4

The crust and upper mantle

Question 5

What is the asthenosphere?

Answer 5

The upper mantle just below the lithosphere

Question 6

How do we know the plates move?

Answer 6

The plates used to be joined as one giant plate know as Pangea.

Fossils of the same species were found on the east of South America and west Africa suggesting they were once all joined

Question 7

Describe a constructive plate boundary

Answer 7

Where 2 oceanic plates are moving away from each other.

Magma is drawn up in the gap forming new crust when it cools

Question 8

Give an example of a constructive plate boundary

Answer 8

Mid-Atlantic Ridge

Question 9

Describe a destructive plate boundary

Answer 9

Where an oceanic plate meets a continental plate and the denser oceanic plate is subducted underneath the less dense continental plate

Question 10

Give an example of a destructive plate boundary

Answer 10

The Andes Mountains, Peru, Chile

Question 11

Describe a conservative plate boundary

Answer 11

Where 2 plates slide past eachother

Question 12

Give an example of a conservative plate boundary

Answer 12

San Andreas Fault, California, USA

Question 13

Describe a collision plate boundary

Answer 13

Where 2 continental plates collide pushing upwards to form mountains

Question 14

Give an example of a collision boundary

Answer 14

The Himalayas, Asia

Question 15

Describe the Hot-spot Theory

Answer 15

The Hot-spot Theory is the idea that magma plumes rise in the mantle causing islands such a Hawaii miles away from plate boundaries

Question 16

What is the scaled called used to measure volcanic eruptions?

Answer 16

VEI - Volcanic Explosivity Index

From 1 - 8

Question 17

What is the most common scale used to measure the magnitude of earthquakes?

Answer 17

The Richter Scale

1-10 but each level is 10x stronger than the previous level

Question 18

How are volcanic eruptions predicted?

Answer 18

Tiltmeters - detect when volcanoes swell up

Seismometers - monitor earth tremors (which increase as magma rises)

Aircraft - record the levels of gas given off by a volcano

Question 19

How are earthquakes predicted?

Answer 19

Seismometers - sense vibrations in the earth’s crust

Radon Gas - a gas that escapes from cracks in the earth (more gas means greater risk of earthquake)

Question 20

At what plate boundaries are earthquakes most common?

Answer 20

Destructive boundaries
Conservative boundaries
Collision boundaries

Question 21

At what boundaries are volcanoes formed?

Answer 21

Constructive boundaries

Destructive boundaries

Question 22

State an earthquake that occurred in an LEDC

Answer 22

Haiti 2010
7 on the Richter scale 
220,000 deaths 
300,000+ injured 
Hospitals and schools destroyed 
Airport and port damaged