Unit 1 - Hazardous Earth Flashcards
On average, how thick is the earths crust?
50km
How thick is the mantle?
2900km thick
What are the two parts of the mantel?
Lithosphere and asthenosphere
How thick is the outer core?
2266km
What is the temperature of the inner core?
5700 C
What is the lithosphere
The uppermost layer of the earth, the top part of the mantle and the crust
What is the asthenosphere
Part of the mantle, semi molten layer beneath the tectonic plates
Give 3 points about continental crust
Thick granite (10-15 miles)
Low density
Floats high on mantle
Give 3 points about oceanic crust
Very thin (1-3 miles)
High density
Basalt rock
What is the difference between oceanic and continental crust
Oceanic crust is below water, continental crust is below ground
Where is the heat from the earth from? (2)
50% from radioactive decay
50% from the Big Bang
Why do tectonic plates move?
Due to convection currents
Explain what convection currents are
When the rock is heated near the core, it rises, travels across and cools when get closer to the surface.
Why is the earths crust unstable? (2)
Plates are moving
Plates move in different directions
What is continental drift?
250 million years ago, the land masses were one big continent called Pangea. They slowly began to drift away into the continents we know today
Give 3 pieces of evidence for continental drift
The fossil of the Mesosaurus are found in Africa and South America yet it can’t swim long distances
Some continents interlock like a jigsaw
Plants and animal fossils are similar in India and Australia
What are the 4 types of plate movements?
Collision, convergent, divergent and conservative
What is a divergent movement?
Moving away form each other (both oceanic)
What is a collision movement?
Moving towards each other (both continental)
What is convergent movement.
Oceanic plate sub-ducts beneath a continental plate
What is conservative movement?
Sliding past each other (both continental)
What is a hotspot?
A place in the centre of a plate where magma rises
How does a hotspot cause the formation of a volcano?
The hotspot causes the lithosphere to melt so magma pushes through the crust
Where can volcanoes form?
Plate boundaries
Middle of plates e.g hotspots
What does the volcanic explosivity index show
It measures the destructive power from 1 (lowest) to 8 (highest)
What are volcanic bombs?
Large pieces of rock ejected from the volcano
What is a volcanic cloud?
Gas, steam and ash escaping from the volcano
What is pyroclastic flow?
Hot gas and volcanic matter from the volcano
What forms the sides of a volcano that was formed from a hotspot
Layers of pyroclastic flow over time
What are the two types of volcano?
Composite and shield
What is a composite volcano (shape, lava, frequency, plate boundaries)
Pointes / coned
Viscous (sticky)
Very rare, value of 6
Convergent
What is a shield volcano? (shape, lava, frequency, plate boundaries)
Quite flat and broad
Runny and quickly spreads
Very frequent, value of 1 or 2
Divergent
Give an example of a composite and shield volcano
Pinatubo
Queen Mary’s Peak
How did the Montserrat eruption happen? (2)
North and South American plates sub ducted under Caribbean plate
The me,ted plate was less dense so magma rose
Where is Montserrat? (2)
Caribbean on a small island
North America
Give 3 primary effects of the Montserrat eruption
2000 people left straight away
9000 in total left
Killed 19 people
Give 3 secondary effects of the Montserrat eruption
The southern area was an exclusion zone
Airport was destroyed, no tourists
Dark tourism, people visit for respect
Give 3 immediate responses on the Montserrat eruption
Made shelters in an old prison for homeless
Scientists set up warning systems
UK government sent £17 million
Give 3 long term responses to the Montserrat eruption
UK sent £41 million in total
Mainly elderly population
South of island is still out of bounds
How do earthquakes occur (4)
Conservative plate movement
Concentrated along fault lines (fractures in crust)
Friction builds up as they move against each other with a lot of pressure
When this is suddenly released, the energy is sent out as seismic waves
What is the epicentre
The point on the earths surface above the focus
What is the focus
The point inside the crust where the pressure is releases
What does the Richter scale do
It measures how big the earthquake is (strength or magnitude) between 1 and 10
What is a seismometer
It measures and records seismic waves
How are tsunamis formed? (3)
Destructive or convergent plate movement causes an earthquake
Sea above earthquake is forced upwards
Sea movement causes tsunami
Give 2 points about Haiti’s location
North America
In the Caribbean
Give 3 key facts about the Haiti earthquake
300,000 people injured
250,000 homes destroyed
Magnitude of 7 on the Richter scale
Why did so many people die in the Haiti earthquake (2)
Diseases (didn’t move the bodies)
Poor construction of buildings, not earthquake proof
Give 3 primary effects of the Haiti earthquake
300,000 people injured
230,000 people died
250,000 buildings destroyed
Give 3 secondary effects of the Haiti earthquake
Cholera outbreak due to poor sanitation
500,000 people still living rough
3000 temporary tent school set up
Give an immediate response to the Haiti earthquake
Healthcare supplies to limit diseases
Give 3 long term responses to the Haiti earthquake
Only received 2% of the gift aid they were meant to get
$330 million by the EU in gift aid
4.3 million people were supplied with food rations in the following weeks
Give 3 key facts about the Japan earthquake
9 magnitude
Largest in Japan’s history
11th march
Give 3 primary effects of the Japan earthquake
1700 people died or are missing
4 million people without power
215,000 people living in government shelters
Give 3 secondary effect of the Japan earthquake
3 workers suffered from radiation exposure
Radiation leaks from damaged nuclear plants
15,000 people died
Give 3 immediate responses to the Japan earthquake
Warning systems allowed people 20 minutes
Japanese Red Cross gave $1 billion in donations
340,000 people needed help for essential supplies
Why weren’t there any long term responses to the Japan earthquake?
The immediate responses were so good
Describe the climate of land (2)
Warmer as dark surfaces absorb sunlight but cools quicker as only the surface is heated
Low pressure as the heated air rises
Describe the climate of the sea (2)
Takes longer to absorb heat (a lot is reflected) but also longer to cool down as 30m deep can be absorbed
High pressure as air remains cooler and denser
Why do ocean currents occur?
Water further from the equator is cold and dense so it sinks
Water closer to the equator is warmer so it rises
This sets ups many convection currents around the earth
What is solar insulation
The amount of suns energy
Why is wind created?
Difference in air pressure causes the air to move
Give 2 reasons for different temperatures in the world
Ocean currents warm or cool an area
Nearest the equator
What does ITCZ stand for?
Inter-tropical convergence zone
What are Hadley cells?
The largest cell in the ITCZ which is caused by heating and cooling and create the worlds high and low pressure system
What is the global circulation model?
A theory that explains how the atmosphere operates in a series of 3 cells each side of the equator
What is the engine that drives the global circulation model?
Intense heating at the equator
What are trade wins
Winds that go towards the Equator
What are westerlies
Winds that go away from the equator
What are the three cells that make up the global circulation
Hadley cells, polar cells, and Ferrel cells
Why is there low pressure at the equator
Due to rising and expanding air
What happens at Polar cells
Cold air sinks at Poles and starts to rise again
What type of weather occurs at high-pressure
Clear skies and sunny
What type of weather happens at low-pressure
Cloudy and rainy
What are pressure belts
A belt of high or low pressure around the Earth
Why is it windy and rainy near the Equator
There is low pressure causing air to rise and then fall as rain and there are Tradewinds
What is the orbital theory for climate change
The ellipse shape of the Earth mean that the light is concentrated on certain areas of the earth
What is the eruption for climate change
A super volcano erupted causing there to be a layer of sulphur in the air which cooled down the Earth and caused a year without summer
What is the asteroid collision theory for climate change
And astroid will collide with the Earth causing a layer of dust and ash blocking sunlight
What are sunspots
Areas of the Sun that are extremely hot causing more solar energy
What is the definition of weather
The daily changes in temperature, sunshine and wind direction etc
What is the definition of climate
The patterns in weather over a long period of time usually 30 years
How are ice cores used to observe the past climate (2)
Each layer represents a year
Air bubbles of CO2
How can tree rings be used toto observe past climate (2)
They will be thicker when it is warmer
Each way is a year
How can historical sources be used to observe past climate (2)
Old photos, drawing and paintings of landscapes
Written records e.g diaries
What is the greenhouse effect
When greenhouse gases trap heat from the Sun and keep the Earth insulated
What is the main greenhouse gas?
CO2
Where is CO2 produced (2)
Factories
Burning fossil fuels
What is the ITCZ?
A zone of convergence at the equator where the trade winds meet, it is a low pressure pelt and migrates with the changing position of the thermal equator
Why does the equator slightly change position
Due to the position of the earth around the sun
