Tectonics

Question 1

Crust

Answer 1

Thinnest layer of Earth

Between 5 and 70km thick

Solid rock broken up into pieces called tectonic plates

Question 2

Mantle

Answer 2

Thickest layer 2900km

Moves slow big circles caused by convection currents

1000 degrees near crust
3700 degrees near outer core

Semi-molten (semi-liquid rock)

Question 3

Outer core

Answer 3

Semi liquid iron

3700 - 5000 degrees

2300km thick

Iron here is liquid and magnetic

Question 4

Inner core

Answer 4

1250km thick

Hottest part of earth

5000 degrees

Made up or iron and nickel under pressure

Question 5

Wegener’s theory

Answer 5

Jigsaw fit

All the countries of the world were once joined together and then had been moved apart

Called Pangea

Question 6

Evidence for Continental Drift

Answer 6

Fossil evidence

Fossils found in countries so far away it would be impossible for the animal to get there unless all the countries of the World were connected

Question 7

Convection currents

Answer 7

movements of volcanic rock in mantle

Question 8

Palaeomagnetism

Answer 8

the study of the Earth’s magnetic field preserved in rocks

Question 9

What are the tectonic plate

Answer 9

Pacific plate
North American plate
South American plate
Eurasion plate
Cocos plate
African plate
Nazca plate
Indo-australian plate
Juan de Fuca playe

Question 10

Subduction zone

Answer 10

where one plate is forced downwards below another plate and grinds past it causing huge amounts of friction and heat

Question 11

Destructive plate boundary

Answer 11

where two plates are moving towards each other

continental crust | oceanic crust

Question 12

Fold mountains

Answer 12

large mountain ranges formed by the collision and ‘folding’ of two plates as they plates continually push into one another.

Question 13

Ocean trench

Answer 13

a particularly deep point of the ocean bed where the oceanic and continental crust have dragged each other downwards

Question 14

Plate boundary

Answer 14

where two very large crustal plates meet on the earth’s surface

Question 15

Oceanic crust

Answer 15

plate that is made up of more dense rock

Question 16

Composite volcano

Answer 16

A very steep volcano formed at a destructive boundary

Question 17

Why earthquakes are often found at plate boundaries

Answer 17

Most earthquakes occur due to the movement and interaction of tectonic plates

Tectonic plates constantly shift and collide with one another creating eargtquakes at their boundaries

Question 18

How are volcanoes found at divergent plate boundaries

Answer 18

Divergent boundaries - occurs when 2 tectonic plates moving away from each other

As they separate magma from the mantle can rise to fill the gap creating new crust and forming volcanic ridge

Question 19

How are volcanoes formed at convergent boundaries

Answer 19

Occur when 2 tectonic plates are moving towards each other

If 1 plate is denser than the other it can sink beneath the other in a process called subduction

This subduction can cause sinking plate to melt leading to the formation of a volcanic arc

Question 20

Why are volcanoes rarely formed at transform boundaries

Answer 20

There is little or no magma available at the plate boundary

Question 21

Why are convection currents important

Weather

Answer 21

Convection currents in the Earth’s atmosphere are responsible for creating weather patterns such as thunderstorms, tornados and hurricanes

Understanding these currents are important for predicting weather and preparing for severe weather events

Question 22

What forms at convergent collision boundaries

Answer 22

Fold mountains

Volcanoes

Tsunamis

Composite volcano

Earthquakes

Question 23

What forms at conservative boundary

Answer 23

Earthquakes

Question 24

What is formed at divergent plate boundary

Answer 24

Shield volcano

Can cause tsunamis

Yes but frequent and small earthquakes

Question 25

What happens at conservative plate boundaries

Answer 25

fault lines will be formed These are plate boundaries where two plate are either slipping past each other in opposite directions or at different rates in the same direction

Question 26

What happens at divergent plate boundary

Answer 26

the plates move apart from one another When this happens the magma from the mantle rises up to make new crust

Question 27

Causes of Montserrat volcanic eruption

Answer 27

on a destructive plate margin The 2 plates converge due to convection currents As the two plates merge the oceanic plate is sub-ducted under the continental plate As its forced down pressure increases which triggers earthquakes heat produced by friction melts the descending crust to form molten magma

Question 28

Impacts of Montserrat volcanic eruption

Answer 28

2/3 of the island became covered in ash Ash polluted air increasing breathing difficulties 50% population evacuated north of the island into temporary shelters Forest fires and tsunamis were caused by the pyroclastic flows The only airport was closed

Question 29

Causes of Haiti earthquake

Question 30

Impacts of Haiti earthquake

Answer 30

Haiti debt $4.5Bn 50% population in debt earn less than $1 a day 70% population unemployed For every 1 person Haiti's government has $450 of debt

Question 31

Conservative fault

Answer 31

Plates slip past each other

Question 32

Causes of Haiti earthquake

Answer 32

Happened on the caribbean tectonic plate where earthquakes often occur The conservative fault caused friction between the North American Plate and the Caribbean Plate which lead to the earthquake

Question 33

Why were the impacts of Haiti earthquake so bad

Answer 33

Poorly built buildings fell on people and trapped them High magnitude Haiti was near the epicentre

Question 34

Causes of a tsunami in example location 2004 indonesia

Answer 34

9.1 magnitude earthquake off the coast of country Caused as epicentre was located in the Indian Ocean on the ocean floor which is where tsunamis are most powerful

Question 35

Impacts of Indian Ocean Tsunami of 2004

Answer 35

Killed 230,000 people 1.7 million people homeless Just under $10 billion in debt 179,000 buildings and homes destroyed 170,000 people died 20-30 minutes after tsunami came

Question 36

Constructive

Answer 36

Divergent

Question 37

Destructive

Answer 37

Convergent

Question 38

Conservative

Answer 38

Transform

Question 39

Epicentre

Answer 39

The point directly above the centre of the earthquake on the earth’s surface

Question 40

Focus

Answer 40

Where the pressure is released underground

Question 41

2 major categories tectonic plates

Answer 41

Continental Oceanic

Question 42

What subducts in a convergent plate boundary

Answer 42

Oceanic crust subducts under land crust Because oceanic crust is denser

Question 43

What subducts at transfom plate boundary

Answer 43

No subduction when they meet