AQA A-Level Geography - Hazards Practice Questions

Describe the inner core (2)

1) Solid ball + super hot, 6000

2) Iron + Nickel

Describe the outer core (3)

1) semi-molten + 4000-5000°

2) iron and nickel

Describe the mantle (3)

1. mostly made of silicate rocks

2. 3000°

3. largest part of the earth

What is the asthenosphere?

the semi-molten, more ductile and plastic like middle section of the mantle

What is the lithosphere?

the rigid top part of the mantle and the crust together

Outline the main source of internal energy in Earth.

the left over heat from when the Earth was formed and from the radioactive decay if elements e.g uranium

State the difference between continental and oceanic crust

continental: thick and less dense

oceanic: thinner and more dense

Describe the crust (2)

1. the outer layer of the Earth

2. 4.8-6.9km thick

What are the 3 theories of how tectonic plates move (3)

convection currents

slab pull

ridge push

Outline the global distribution of volcanoes (4)

- Most volcanoes occur on plate margins at destructive margins

- around 75% are around the 'Ring of Fire' surrounding the Pacific Ocean

- Volcanoes can also be found at hot spots in the middle of plates, like Hawaii in the central Pacific

- at mid ocean ridges

What is a hazard?

something that is a potential threat to human life or property

What is a geophysical hazard?

hazards caused by land processes, e.g earthquakes, volcanic eruptions, landslides, tsunamis

What is an atmospheric hazard?

hazards caused by climatic processes e.g tropical cyclones, stroms, drought, extremes of hot or cold weather and wildfires

what are hydrological hazards?

hazards caused by water movement, e.g floods and avalanches

What is meant by the term "Disaster"?

when a hazard actually seriously affects humans (over 10 casualties)

What is meant by the term "Risk"?

the likelyhood that humans will be seriously affected by a hazard

what is vulcanicity?

The process through which gases and molten rock are either extruded on the Earth's surface or intruded into the Earth's crust.

What is meant by the term "Vulnerability"?

how susceptible a population is to the damage caused by a hazard

What is the economic circumstance that affects people's perception of hazards?

Wealth, e.g, richer people are able to move areas less prone to hazards, or build homes able to withstand hazards

What are the cultural circumstances that affect people's perception of hazards?

religion; e.g, people believe natural disasters are acts of God sent to punish people

What are the social circumstances that affect peoples perception of hazards?

past experience, personality and education

Explain how past experiences can affect peoples' perception of hazards

people who live in hazard prone areas may have experienced hazards before, which may affect the perceived risk of future hazards

Explain how someone's personality can affect people's perception of hazards

some people fear hazards, some find them exciting

Explain how someone's education can affect people's perception of hazards

better education = better understanding of how to mitigate the impacts and reduce risks

what is meant by the term mitigation?

minimise the impacts of future disasters. mitigation can happen before or after a hazard occurs

what is meant by the term preparation?

planning how to respond to a hazard using scientific research and past events e.g making sure there are warning systems in place or educating people about how to evacuate safely if there is a cyclone

Give some examples of preparation

making sure there are warning systems in place or educating people about how to evacuate safely if there is a cyclone

State some examples of mitigation

building flood defences or adding fire resistant roofs to buildings in places prone to wildfires.

what is meant by the term response?

how people react when a disaster occurs

Give some examples of response

rescuing people who have been trapped or evacuating people in the danger zone

what is meant by the term recovery?

getting the affected area back to normal

Give some examples of recovery

repairing sites or rebuilding houses and restoring services such as medical care and electricity

what is meant by the term fatalism?

the viewpoint that hazards are uncontrollable, natural events and that some losses have to be accepted as there is nothing we can do to stop them. this is known as a passive response

outline how convection currents move tectonic plates [4]

1. radioactive elements from the Earth's core produce heat which causes magma to rise into the asthenosphere

2. as the magma nears the earth's surface, it cools and sinks back towards the core

3. this circular motion of magma rising and falling is what convection currents are

4. and this process causes the plates in the crust to move

outline the process of gravitational sliding/ridge push in relation to plate movement [7]

1. divergent/constructive plate margin

2. magma rises through the gap, which is very hot initially

3. it heats the surrounding rocks, causing them to expand and rise above the surface of surrounding crust, forming a slope

4. the crust cools and becomes denser. Gravity causes the denser rock to move downslope, away from the plate margin

6. this puts pressure on the tectonic plates, causing them to slide apart

7. this pressure is known as gravitational sliding

Outline the process of slab pull [3]

1. dense oceanic plate is subducted by the less dense continental plate

2. the theory is because the oceanic plate is denser than the hotter mantle beneath it

3. the contrast in density causes the plate to sink into the mantle and pull the rest of the slab/plate with it.

what plate margins do earthquakes AND volcanoes occur at?

constructive plate margins

Outline the process of seafloor spreading and how it forms mid-ocean ridges [6]

1. tectonic plates diverge, magma rises up to fill the gap cools to create new crust which expands around the surrounding crust

2. overtime the new crust is dragged apart and even more crust forms between it

3. when this happens at a plate margin under the sea, the sea floor gets wider

4. this process is called seafloor spreading

5. this process eventually creates structures known as mid-ocean ridges

6. a similar process occurs at land margins

What is a destructive/convergent plate boundary?

where 2 plates move towards each other where the denser crust is subducted beneath the less dense crust. (landforms: fold mountains, trenches, island arcs

what 3 landforms do destructive/convergent plate boundaries form?

fold mountains, trenches, island arcs

Outline the process of liquifaction [4]

when soil is saturated with water, the vibrations of an earthquake can causs it to act like a liquid

2. This makes the soil weaker and easier to deform so it's more likely to subside especially where it has heavy weight ontop of it e.g a building

Outline how tsunamis form [4]

1. triggered by underwater earthquakes

2. earthquakes cause the seabed to move, which displaces the water

3. waves radiate out of the epicentre of the earthquake

4. greater the movement of the seabed, the more water displaced and the larger the wave

what is a constructive/divergent plate boundary?

2 plates move away from each other.

Outline the different characteristics seismic waves can have [4]

1. body waves abd surface waves

2. surface waves are the slowest

3. primary waves travem fastest and are compressed vibrating in the direction they travel in

4. secondary waves travel at half the speeds of P waves and vibrate at right angles to the direction of travel

what landforms do constructive/divergent plate boundaries form?

ocean ridge, volcanoes and rift valleys

Outline how Island arcs develop [4].

1. destructive plate boundaries where the denser oceanic plate sinks beneath the lighter oceanic plate

2. the denser oceanic plate begins to melt as it enters the asthenosphere due to friction, feeding the magma, causing the magma to erupt

3. and form composite volcanoes on the overriding plate

4. they form parallel to sea trenches

what is a conservative/transform plate boundary?

where 2 plates slide past each other

what is seismicity?

the occurrence of of earthquakes or tremors in a region

Outline how young fold mountains develop [4]

1. mountains that from at destructive plate boundaries

2. plates move towards each other

3. the denser plate is subducted beneath the other

4. the earth is compressed upwards forming mountains

Outline how rift valleys develop [4]

1. form due to rift lines being perpendicular to the plates, which may have formed due to the crust being deformed by bulging magma

2. if the plates are moving apart beneath the faults, sections of the land above literally drop down to create a rift valley. a clear example of this is the East African rift system.

Outline how ocean ridges form (ridge push/ gravitational sliding underwater) [4]

1. where diverging/constructive plates are underwater

2. magma rises through the cracks , then cools to form new crust

3. overtime even more magma rises and cools to form even more new crust, forcing the sea floor further apart. this is known as sea floor spreading.

4. mid ocean ridges, are ridges of higher terrain on either side of the margin

Outline how deep sea trenches form [4]

1. occur at destructive plate boundaries where the plates move towards each other

2. the denser oceanic plate subducts beneath the lighter oceanic plate

3. causes the seafloor and outermost lithosphere to bend

4. and create a steep v - shaped depression under the sea where the plates meet

Outline how volcanoes are formed [4]

1. at destructive plate boundaries, oceanic is subducted under continental crust or oceanic and oceanic

2. the more dense crust is melted by friction and contact with the upper mantle, increasing the magma

3. the magma is less dense than continental crust, so the magma will rise up and erupt to form volcanoes

What is a magma plume?

A vertical column of extra-hot magma that rises up from the mantle

what landform forms above magma plumes?

volcanoes

Outline how volcanoes can form on magma plumes [4]

1. magma plume remains stationary overtime but the crust moves above it

2. volcanic activity in the part of the crust that was above the magma plume decreases as it moves away

3. new volcanoes form in the part of the crust that is now above the magma plume

4. as the crust moves, a chain of volcanoes is formed

What 3 characteristics of volcanic activity occur at constructive margins?

1. basaltic lava

2. can form ocean ridges if underwater

3. can form rift valleys if on land

What 2 characteristics of volcanic activity occur at destructive margins?

1andesitic and rhyolitic lava which causes blockages cleared by violent eruptions due to the high viscosity creating pressure

What is pyroclastic flow?

A mixture of superheated gas, ash and volcanic rock that flows down the side of a volcano it travels at high speed and causes widespread death and destruction.

Describe lava flows (3)

Lava that flows down the sides of volcanoes

speed and distance travelled depend on the temperature and viscosity

most are relatively slow so people have time to evacuate areas

destroy buildings and vegetation

What are volcanic gases?

Lava contains gases such as carbon dioxide and sulphur dioxide which can be harmful to humans and animals if breathed in.

What is pyroclastic/tephra and ash fallout?

material that has been ejected from a volcano during an eruption and falls back to the ground

when fallout consists of mostly ash, its called ash fallout

State impacts of pyroclastic/tephra and ash fallout (3)

1. material can travel thousands of kilometres from the volcano

2. heavier particles deposited earlier than the light ones (larger material is found closer to volcano and lighter material is found further away)

3. can damage buildings and kill or injure people, vegetation and hinder transport

Describe what acid rain is and the threat it poses to human life (2)

sulphur dioxide released from volcanic eruptions can react with water vapour in the atmosphere and create a weak sulphuric acid

can damage ecosystems and can deteriorate limestone buildings

What are mudflows (lahars)? (3)

when volcanic material mixed with large amounts of water

move very quickly and can travel for tens of kilometres

mudflows can bury or destroy natural habitats settlements and infrastructure

What is the definition of the term magnitude? what is used to measure it

volcanic events range from small slow lava flows to huge eruptions. measured using Volcanic Explosivity Index, 0-8 based on how high it is blasted

What is the definition for the term frequency?

how often volcanic eruptions occur

what is the definition for the term predictability?

the regularity with which a volcano erupts can help scientists to predict when it might occur

How do people adapt to volcanic events? (2)

buildings can be strengthened to reduce the chance of collapse if volcanic ash lands on them

people can capitalise on the opportunities of living near a volcano e.g, by farming (fertile soil) or working in the tourist industry

How do people prepare for an earthquake? (3)

authorities can install monitoring systems and make plans for how they evacuate people if there is an eruption

emergency shelters and kits

communities can set up search and rescue teams

How do people prevent volcanic eruptions form posing risk to people?

authorities can prevent the land around an active volcano from being developed

Outline how landslides/avalanches form [4]

1. shaking of the ground dislodges rock, soil or snow causing valanches or landslides tht move downslope quickly

2. shaking can also loosen ground material making it easier for water to infiltrate the weight of the extra water could trigger a landslide wven after the ground shaking has stopped.

LIC EARTHQUAKE CASE STUDY, HAITI: background info (3)

- 7 on the Richter scale

- occurred in densely populated capital city, Port-au-Prince

- Haiti's GNI is only $660 per person

- occurred along a conservative plate margin

LIC EARTHQUAKE CASE STUDY, HAITI: State some primary impacts of the Haiti earthquake (5)

- 230,000 people killed (social)

- 180,000 homes destroyed (social)

- 5000 schools damaged (social)

- 70% of buildings collapsed (social)

- 60% infrastructure destroyed (social)

LIC EARTHQUAKE CASE STUDY, HAITI: State some secondary impacts of the Haiti earthquake

- 2 million affected and 1.5 million homeless (social)

- cholera due to lack of sanitation and burst water pipes which led to another 6,900 deaths (social)

- total damage bill was $11.5 million

LIC EARTHQUAKE CASE STUDY, HAITI: State some immediate responses to the earthquake (4)

- search and rescue by local people used highly trained sniffer dogs

- Dominican Republic sent supplies of food , water and heavy lifting machinery

- D.R made their own hospitals available permitted people to cross the border to receive aid.

- Iceland had an emergency response team in the country within 24 hours

LIC EARTHQUAKE CASE STUDY, HAITI: State some long term responses (4)

- 3/4 buildings were inspected and repaired

- 200,000 received cash or food for public work such as clearing rubble

- several thousand people have decided to move away from Port au Prince to stay with family

- some aid money went to paying Haitian engineers to colour tag buildings to decide whether they should be rebuilt or not

HIC EARTHQUAKE CASE STUDY: JAPAN 2011: what was the measurement of the earthquake on the richter scale?

- 9.0 on the Richter Scale

HIC EARTHQUAKE CASE STUDY: JAPAN 2011: what were some primary impacts (4liq)

- over 15,000 people died

- damaged over 330,000 buildings (railways, roads, hospitals)

-blackouts, Over 4.4 million households were left without electricity in North-East Japan.

- liquefaction occurred destroying over 1000 buildings

HIC EARTHQUAKE CASE STUDY: JAPAN 2011: what were some secondary effects?

- most expensive natural disaster in history economic cost of $235 billion

- lead to an over 40m high tsunami

- Rural areas remained isolated for a long time because the tsunami destroyed major roads and local trains and buses.

as sections of the Tohoku Expressway were damaged.

HIC EARTHQUAKE CASE STUDY: JAPAN 2011: what were some immediate responses? (3)

- Japan Meteorological Agency issued tsunami warnings three minutes after the earthquake. scientists were able to predict where the tsunami would hit after the earthquake using modelling and forecasting technology so that responses could be directed to the appropriate areas.

- Rescue workers and around 100,000 members of the Japan Self-Defence Force were dispatched to help with search and rescue within hours of the tsunami hitting

-The government declared a 20 km evacuation zone around the Fukushima nuclear power plant to reduce the threat of radiation exposure to local residents.

HIC EARTHQUAKE CASE STUDY: JAPAN 2011: what were some long term responses?

- Reconstruction Policy Council was created to develop a national recovery and reconstruction outlook for tsunami-resilient communities

- central government decided on a coastal protection policy, such as seawalls and breakwaters which would be designed to increase their resilience in the event of future tsunamis

Describe the conditions needed for a tropical storm to form (3)

- warm sea water in excess of 27 degrees C to at least 50m below the surface

- a location at least 5 degrees from the equator

- converge of air in the lower atmosphere

What is the Coriolis Effect?

a force cause by the Earth's rotation. It deflects the path of the winds but it is weak at the equator.

Where do tropical storms form?

over the tropics because it is warm enough

What is the difference between a hurricane and a tropical depression?

a tropical depression is when a tropical storm is at its early stages, whereas a tropical storm is a spinning storm with strong winds and torrential rain that move at or above 74mph

What scale do we use to measure tropical storms?

Saffir-Simpson Scale (the category of the tropical storm is determined by the windspeed)

What are the 4 hazards associated with tropical storms?

- strong winds

- storm surges

- river flooding

- landslides

Give 3 impacts of strong winds from a tropical storm?

- buildings damaged

- damaged power lines

- transport disruption due to debris

Give 4 impacts of storm surges from a tropical storm

- loss of life

- salinisation of agricultural land

- salt water pollutes fresh water supplies

- flooding of homes and businesses

Give 2 impacts of river flooding from a tropical storm

- more than 200mm of rain in just a few areas in uncommon

- causes flash floods, particularly in urban areas

Give the impact of landslides from a tropical storm

-estimated 90% of landslides are associated with heavy rainfall

- water weakens the cohesion within soil/rock on a slope that triggers slope failure

HIC TROPICAL STORM CASE STUDY: HURRICANE SANDY, USA: Give some background info on this hurricane

- category 3 hurricane on the saffir-simpson scale

- 29th october 2012 nicknamed as "superstorm sandy"

- fuelled by the caribbean sea

HIC TROPICAL STORM CASE STUDY: HURRICANE SANDY, USA: State the primary effects of this hurricane (4)

- houses destroyed by ferocious winds

- 160 people killed by the storm

- roads were smeared

- ruptured gas pipes

HIC TROPICAL STORM CASE STUDY, HURRICANE SANDY, USA: State the secondary effects of this hurricane (6)

- $63 billion spent in USA

- 30,000 people displaced

- ruptured gas pipes ignited fires

- many people suffered from hypothermia after a cold snap followed sandy

- massive crime wave because of looting due to lack of electricity

- new york marathon cancelled so economic damage from lack of tourism

HIC TROPICAL STORM CASE STUDY, HURRICANE SANDY, USA: State immediate responses to the hurricane (3)

- The American red cross recruited 4000 volunteers to help people affected by the storm

- in new york the federal government provided emergency supplies of petrol

- power companies gradually restored electricity and power and federal agencies and emergency services supplied their additional support

HIC TROPICAL STORM CASE STUDY, HURRICANE SANDY, USA: State long term responses to the hurricane

- several agencies in the US raised money

- a live telethon concert in november 2012 raised over $20 million

- in december 2013 an estimated 30,00 people still remained displaced

LIC TROPICAL STORM CASE STUDY: TYPHOON HAIYAN: PHILIPPENES: Give some background info

- category five typhoon

LIC TROPICAL STORM CASE STUDY: TYPHOON HAIYAN: PHILIPPENES: Give primary impacts (3)

- 1.1 million tonnes of crops destroyed

- airport badly damaged

- 4.1 million people were made homeless

LIC TROPICAL STORM CASE STUDY: TYPHOON HAIYAN: PHILIPPENES: Give secondary impacts (4)

- The overall cost of damage was around $12 billion

- Education was disrupted as many schools were destroyed.

- Rice prices had risen by nearly 12% by 2014.

- 8 people killed in a stampede for food supplies