Year 11 Plate Tectonics

Question 1

Crust

Answer 1

Solid, hard outer shell

Question 2

Mantle

Answer 2

Soft molten rock about 3800*C

Question 3

Outer core

Answer 3

Liquid iron and nickel

Question 4

Inner core

Answer 4

Combination of nickel and iron, solid, up to 5500*C

Question 5

How do we know about the different layers that exist

Answer 5

Because the seismic waves are refracted and travel at different speeds which gives us an image

Question 6

Continental crust:
Where?
Thickness?
Density?
Age?
Rock type?

Answer 6

Lies under continental land masses
25-100km thick
less dense, doesn’t sink
3-4 billion years old
new crust never formed and can’t be destroyed
Granite with large crystals, as rock cools slowly

Question 7

Oceanic crust
Where?
Thickness?
Density?
Age?
Rock type?

Answer 7

Lies under oceab
5-10km thick
more dense, sinks into mantle when meets continental
Oldest only 180 million years old
Constantly formed at constructive boundaries where it’s destroyed
Basalt with small crystals as cools quickly

Question 8

What are tectonic plates

Answer 8

Large sections of the Earth’s crust able to move separately from each other

Question 9

Conservative margin: what? Earthquakes? Volcanoes? Example

Answer 9

Plates more past each other, Earthquakes, no volcanoes e.g. Haiti Earthquake 2010 American and Caribbean

Question 10

Constructive margin: what? Earthquakes? Volcanoes? Example

Answer 10

Plates move apart, earthquakes and volcanoes e.g. Iceland, Eurasian and n’ American

Question 11

Destructive margin: what? Earthquakes? Volcanoes? Example

Answer 11

Plates moving together, earthquakes and volcanoes e.g. Chile earthquake 2010 Nazca and s.American plate

Question 12

Why do plates move

Answer 12

Convection current, as magma heated it rises, as it rises it cool so sinks again causing the plates above to move

Question 13

What’s ridge push

Answer 13

As the lithosphere cools, it becomes denser and starts to slide down, away from the ridge, causing the plates to diverge

Question 14

What’s slab pull

Answer 14

At destructive margins, the denser plate subducts down into the mantle due to gravity/ This motion pulls the rest of the plate along with it

Question 15

What happens at constructive plate boundaries

Answer 15

As plates slowly move apart, magma rises to earth’s surface, it cools and solidifies forming new igneous rock. Eventually rock builds up forming a shield volcano, some so large they form islands such as Iceland

Question 16

What happens at destructive plate boundaries (continental and oceanic)

Answer 16

Oceanic plate denser so forced beneath continental, know as subduction zone. As subducted, it melts forming magma and earthquakes triggered. Magma collects and rises up through cracks, building up pressure, triggering volcanic eruptions. Fold mountains formed at subduction zones e.g. Andes

Question 17

What happens at destructive plate boundaries (oceanic and oceanic)

Answer 17

The older, denser oceanic slap is force under the other, creating a trench at subduction zone. Volcanoes formed and earthquakes, same as c+o e.g Pacific and n.American plate

Question 18

What’s the Pacific ring of fire

Answer 18

An area of high seismic and volcanic activity around the Pacific ocean. There are many destructive margins around the Pacific plate which creates tectonic activity

Question 19

What happens when two continental plates converge

Answer 19

Both plates have the same density so both pushed upwards forming mountain ranges. Magma can’s penetrate the thick crust so no volcanoes. The collision of the plates cause many earthquakes such as Himalayas

Question 20

What happens at conservative plate boundaries

Answer 20

Occurs when plates slide past each other in opposite or same direction but at different speeds. Friction is eventually overcome and the plates slip past in a sudden movement causing an earthquake e.g. San Andreas fault

Question 21

Name the point in the crust where the pressure is released

Answer 21

Focus

Question 22

What is the epicentre

Answer 22

The point on the Earth’s surface above the focus where the most intense shaking occurs

Question 23

Factors affecting the impact of an earthquake

Level of development

Answer 23

Richer LICs and NEEs more likely to have the resources and technology for monitoring and prediction

Question 24

Factors affecting the impact of an earthquake

Population density

Answer 24

More densely populated the area, the greater the hazard will be so more deaths and casualties

Question 25

Factors affecting the impact of an earthquake

Communication

Answer 25

Accessibility for rescue teams, earthquakes often damage bridges etc

Question 26

Factors affecting the impact of an earthquake

Time of day

Answer 26

This influences weather people are in their homes, at work or travelling if during rush hour could be devastating

Question 27

Factors affecting the impact of an earthquake

Time of year and climate

Answer 27

Will influence survival rates and the rate that disease is spread. Hot tropical places are particularly bad

Question 28

Richter scale

Answer 28

Measures the magnitude of a tremor using seismograph, has no upper limit, is a logarithmic scale so each is 10x larger than the previous

Question 29

Mercalli scale

Answer 29

Scale from 1-XII and measures the effects of earthquakes. Uses subjective descriptions of the resulting damage

Question 30

Chile earthquake
Date/ GDP ranking
magnitude
focus depth
epicentre
cause

Answer 30

27th February 2010
46
8.8 
35km
11km from Concepcion
Nazca plate and s. American plate (convergent)

Question 31

Haiti earthquake
Date/ GDP ranking
magnitude
focus depth
epicentre
cause

Answer 31

12th January 2010
143
7.0
13km
25km west of port-Au-prince
Caribbean plate and north American plate (conservative)

Question 32

Deaths, injuries, no. of homes damaged- Chile

Answer 32

500 deaths, 12,000 causalities, nearly 400,000 homes damaged

Question 33

Deaths, injuries, no. of homes damaged- Haiti

Answer 33

230,000 deaths, 300,000 casualties, 250,000 homes damaged

Question 34

Secondary effects- Chile

Answer 34

150 deaths from Tsunami,
est $15-30 billion damage
Lost power, fire at chemical plant

Question 35

Secondary effects- Haiti

Answer 35

All hospitals in the capital were destroyed, public phones not available
Looting, debris blocked main road
2 million left without food and water

Question 36

Short term response- Chile

Answer 36

Government vowed to deliver aid quickly
Firefighters combed rubble for people
Army sent 10,000 troops,
curfew imposed to prevent looting 
Communications in the capital restored within 4 days

Question 37

Short term response- Haiti

Answer 37

Government appealed quickly for aid
Over 1st weekend received many food and water packets
Hard to get aid as the port was damaged

Question 38

Long term response- Chile

Answer 38

Month later, government launched a housing reconstruction plan
Strong economy so could rebuild without relying on foreign aid

Question 39

Long term response- Haiti

Answer 39

Dominican republic accepted some refugees

Senegal offered land to anyone in Haiti who wanted it

Question 40

Preparation and protection- Chile

Answer 40

Building code require shake-resistant construction and rapid emergency response
Regular anti-disaster drills
Prepared following 1960 earthquake

Question 41

Preparation and protection- Haiti

Answer 41

Tsunami warning was issued immediately after initial earthquake, but quickly cancelled it
Not prepared as never had an earthquake before
Port-Au-Prince had 2.5 mil population so overcrowded and houses were poorly built