Hazardous Earth

Question 1

why are low lying coastlines vulnerable to tropical cyclones

Answer 1

they are vulnerable to storm surge flooding caused by low air pressure within cyclones

vulnerable to large waves causing flooding driven onshore by intense winds

Question 2

what are 2 data presentation techniques that would show contrasting impacts of a hazard event on different countries

Answer 2

bar graph and choropleth map

Question 3

what is the best technique to measure volcano type

Answer 3

cross section

Question 4

what are 2 ways to predict volcanic eruptions

Answer 4

1) using thermal imaging techniques and satellite cameras to track temperature fluctuations around the volcano which increase when an eruption is imminent
2) measuring gases released by the volcano in order to know the chemical make up of the gases which have increased sulphur content when an eruption is imminent

Question 5

what are 2 ways to predict an earthquake

Answer 5

1) laser beams can be used to detect minor plate movement just before an earthquake
2) a seisometer is used to pick up vibrations in the earth’s crust. An increase in vibrations could indicate an earthquake is about to happen

Question 6

what is atmospheric circulation

Answer 6

movement of air in the atmosphere dominated by 3 large circulation cells in each hemisphere (hadley, ferrel, polar)

Question 7

what is the cause and air pressure of convection air movement

Answer 7

cause; when high amounts of solar radiation heat the ground which heats the air above causing the air to rise. As it rises it cools and condenses forming water droplets and clouds
Air pressure; low as air is moving upwards away from the surface

Question 8

what is the cause and air pressure of subsidence air movement

Answer 8

cause; in places with low intensity solar radiation like the poles the cold dense air sinks towards the ground. As it sinks it warms up so can hold more moisture which prevents clouds forming
air pressure; high as air is sinking

Question 9

how does volcanic activity cause climate change

Answer 9

large eruptions emit dust and sulphur dioxide into the atmosphere which block out or absorb solar radiation so the earth cools

Question 10

how do sunspots cause climate change

Answer 10

sunspots are darker areas on the sun’s surface showing greater solar output. They come and go in cycles of about 11 years

Question 11

how do orbital changes affect climate change

Answer 11

shape of the earths orbit becomes more or less circular over a period of 100,000 years
the tilt of the axis varies between 21 degrees and 24 over 40,000 years
this changes the amount of solar energy received at the earths surface

Question 12

how can asteroid collisions affect climate change

Answer 12

similar to volcanic eruptions in which dust and ash is thrown into the atmosphere blocking incoming sunlight

Question 13

how do ice cores act as evidence for climate change

Answer 13

they are tubes of ice containing trapped air bubbles dating from when the ice was formed showing how muc CO2 was in the atmosphere at that time

Question 14

how do tree rings act as evidence for climate change

Answer 14

wide ring means it was warm but a narrow ring indicates harsh conditions like cold or drought

Question 15

what is thermal expansion

Answer 15

an increase in the volume of water as a result of increasing temperature

Question 16

what are human reasons for uncertainty

Answer 16

future population growth is unknown
emissions per person are linked to wealth but future average wealth is uncertain
humans may carry on polluting or may make a strong effort to reduce emissions
new technology could replace fossil fuels

Question 17

what are physical processes leading to uncertainty

Answer 17

oceans may absorb a lot of co2 but their ability to do this could stop
warmer world could be cloudier, clouds could reflect more solar radiation back into space reducing the warming
ice may start to melt much more quickly

Question 18

where are tropical cyclones known as hurricanes

Answer 18

North Atlantic ocean and East Pacific

Question 19

where are tropical cyclone known as typhoons

Answer 19

Indian ocean

Question 20

what is the coriolis force

Answer 20

a rotational force that affects liquids and gases, caused by the earth’s rotation

Question 21

where are source areas for tropical cyclones found

Answer 21

5-15 degrees north and south of the equator as this is where the ocean is the warmest

Question 22

why are tropical cyclones not found between 0-5 degrees north and south of the equator

Answer 22

because the coriolis force that creates their rotation is too weak

Question 23

how are tropical cyclones formed

Answer 23

when ocean temperatures are 26.5 or above
warm air above the ocean rises leading to strong convection and the formation of thick clouds
as more water is evaporated from the ocean it rises and condenses forming clouds releasing latent heat into the storm (energy source)
storm clouds combine into one large storm which begins to rotate

Question 24

what physical hazards can happen when a cyclone makes landfall

Answer 24

intense wind
intense rain
landslides 
powerful waves
storm surge

Question 25

what is the litosphere

Answer 25

rigid outer layer of the earth made of the mantle and the crust

Question 26

what are the 2 crusts that make up the earth’s tectonic plates

Answer 26

continental crust and oceanic crust

Question 27

what is the continental crust

Answer 27

low density
makes up most of the land area of the earth
25-80km thick
dominated by rocks that cooled below the surface eg granite

Question 28

what is the oceanic crust

Answer 28

high density
6-8km thick
made up of rocks eg basalt

Question 29

what is the asthenosphere

Answer 29

partly molten layer beneath the litosphere on which the litosphere slides

Question 30

what are convection currents

Answer 30

circular movements of heat within the Earth’s core and mantle which drive plate tectonic motion

Question 31

what 3 things cause plate motion

Answer 31

plates are pushed along by convection currents moving sideways just below the crust

elevated parts of divergent boundaries create a force called gravitational sliding

slab pull- old, dense oceanic plate sinks at convergent margins pulling the plate down the mantle

Question 32

what are conservative plate boundaries

Answer 32

where 2 plates slide past each other

Question 33

what are convergent (destructive) plate boundaries

Answer 33

where 2 plates collide

Question 34

what are divergent (constructive) plate boundaries

Answer 34

where 2 plates move apart from each other

Question 35

what is subduction

Answer 35

the process whereby a dense oceanic plate sinks back into the upper mantle

Question 36

what are fold mountains

Answer 36

chains of high mountains produced when tectonic plates collide and the continental crust crumples and is forced upwards

Question 37

what is the fault

Answer 37

major cracks in the crust. when there is movement on the fault often an earthquake will start

Question 38

what are hotspots

Answer 38

places where there is a rising plume of heat from the mantle in the form of an isolated column. The heat generates magma in the upper mantle which erupts as basaltic volcanoes
creates a chain of volcanic islands

Question 39

how does a volcano erupt

Answer 39

when magma beneath the earth’s crust pushes up through fissures and vents and erupts at the surface as lava, ash and gas

Question 40

what is the difference between composite volcanoes and shield volcanoes

Answer 40

composite are more dangerous and found on convergent plate boundaries.
Shield volcanoes are found on divergent boundaries or hotspots

Question 41

what is a tsunami and how are they caused

Answer 41

series of very destructive ocean waves. sub sea earthquakes can displace the seabed and this causes a tsunami