Geography Paper 1 - Natural Hazards

• what is a natural hazard?

  a natural process with the potential of causing death, injury or disruption to humans, or destroy property and possessions.
• what are some factors that affect hazard risk?

  ➤ urbanisation & population density - urban areas are often densely populated, increasing the no. of people at risk.

  ➤ poverty - in poorer regions of the world, more may be forced to live in areas at risk.

  ➤ climate - the atmosphere has more energy in warmer areas of the world, leading to intense storms and hurricanes. some parts of the world are wetter, increasing chances of floods.

  ➤ population - as the world population increases, more people live in areas at risk.
• what are the layers the earth is made up of?

  the inner core, the outer core, the mantle, and the crust.
• what are the two types of the earth's crust?

  oceanic and continental.
• what is the continental crust like?

  it is thick and less dense.
• what is the oceanic crust like?

  it is thin and dense.
• why do tectonic plates move?

  their movement is a result of convection currents in the mantle.
• what are the three main types of plate boundary?

  constructive, destructive, and conservative.
• what happens at a constructive plate boundary (in terms of plate tectonics)?

  plates move apart.
• describe the physical processes that occur at a constructive plate boundary.

  ➤ magma forces its way to the surface from the mantle and breaks through overlying crust.

  this causes an earthquake.

  ➤ on reaching the surface, the magma forms volcanoes.
• what happens at a destructive plate boundary (in terms of plate tectonics)?

  plates move towards each other.

  ➤ continental and oceanic - the denser, heavier oceanic plate subducts under the less dense continental plate.

  ➤ both continental - the two plates collide and the crust becomes crumpled and uplifted.
• what happens at a conservative plate boundary (in terms of plate tectonics)?

  plates move past each other in opposite directions, or in the same direction at different speeds.
• describe the physical processes that occur at a destructive plate boundary.

  ➤ continental and oceanic - as the oceanic plate subducts under the continental, friction between the plates causes strong earthquakes. as the oceanic plate moves downwards, it melts, creating magma which then breaks through to the surface to form steep-sided composite volcanoes.

  ➤ both continental - the collision of the plates and crumpled crust results in the formation of fold mountains (ex. himalayas) and the process causes earthquakes. no volcanoes because of no magma.
• describe the physical processes that occur at a conservative plate boundary.

  ➤ friction between plates causes earthquakes. these quakes come suddenly and unexpectedly - this is bc stresses have gradually built up over the years, and are released suddenly when plates slip and shift.

  no volcanoes because of no magma.
• describe the global distribution of earthquakes.

  earthquakes occur mainly at the margins of tectonic plates, where plates are moving and enormous pressures build then release.

  some don't occur at plate margins, meaning they are caused by human activity such as underground mining or oil extraction.
• describe the global distribution of volcanos.

  volcanos occur in long belts that follow the plate margins. most are at constructive or destructive boundaries.

  this is because they are formed out of magma deep within the earth, which rise to the surface at these margins.

  hotspots are areas away from plate boundaries but have thin enough crust to allow magma to break through.
• where are a majority of active volcanos located?

  ring of fire in the pacific ocean.
• when was the tohoku earthquake, what was its magnitude, where was its epicentre, and what followed it?

  ➤ march 11, 2011

  ➤ magnitude 9.1

  ➤ its epicentre sad 130km off the coast.

  ➤ a huge tsunami followed the quake, devastating the east coast of japan. waves were up to 35m high.
• what were the primary effects of the tohoku earthquake?

  ➤ 16 000 dead.

  ➤ 330 000 homeless.

  ➤ roads and railways severely damaged, including tohoku motorway.

  ➤ liquefaction of the ground (water rises to surface, mixes w/ soil, and turns ground to liquid).

  ➤ the entire NE coastline of japan dropped by 60cm during main quake.
• what were the secondary effects of the earthquake?

  ➤ a huge tsunami of up to 40m high followed.

  ➤ rural areas remained isolated for a long time due to damage to major roads, railways, and public transport.

  ➤ damaged power stations led to power outages.
• what were the immediate responses to the tohoku earthquake?

  ➤ temporary housing projects were immediately constructed by the gov. to provide 200 000 beds to homeless families - camps complete within two weeks.

  ➤ a national warning was sent to everybody's mobile phones, the radio, and the TV within fifteen sec of the quake, giving many a few seconds warning before the main quake and 20min before the tsunami hit.

  ➤ within 8 hours, foreign government emergency response teams from the developed world arrived in the NE with specialist equipment and experience.
• what were the long-term responses to the tohoku earthquake?

  ➤ $250B invested over the next ten years by the gov. to create a strategic recovery plan. this aimed to encourage both business and reconstruction investment to re-stabilise the economy.

  ➤ fukishima power station was fixed and strengthened.

  ➤ a five-year recovery plan was implemented that focused upon rebuilding the infrastructure and key services. this was completed by 2019.
• why was japan able to handle the earthquake so well?

  they had high levels of preparation, which was a huge government investment. the emergency services and military had clean plans to respond to the quake in 2011. japan also had high building standards with earthquake-resistant designs, such as being made out of reinforced concrete or steel.
• when was the haiti earthquake, where was its epicentre, and what was its magnitude?

  ➤ january 12, 2010.

  ➤ the epicentre sat only 15km southwest of the capital city, port au prince.

  ➤ magnitude 7.0
• what were the primary effects of the haiti earthquake?

  ➤ 316 000 dead.

  ➤ over 1M homeless - even in 2011, people remained in makeshift temporary homes.

  ➤ over 250 000 buildings were damaged severely.

  ➤ the port, major roads, and communication links were damaged beyond repair.
• what were the secondary effects of the haiti earthquake?

  ➤ unemployment - 20% of jobs were lost as a result of structural damage at manufacturing facilities.

  ➤ increase in crime levels - many resorted to looting in this time of trouble, and delays in aid distribution led to angry appeals from survivors.

  ➤ morgues were overwhelmed and people were buried in mass graves.

  ➤ people lived in makeshift shanty towns, containing no running water or waste disposal systems.

  an outbreak of cholera in the city occurred as a result of the unhygienic circumstances (mass graves and shanty towns)

  ➤ roads were littered with cracks and fault lines for years.
• what were the immediate responses to the haiti earthquake?

  ➤ many countries responded to appeals for aid, pledging funds and dispatching rescue and medical teams, engineers, and support personell.

  ➤ however, communication systems, transport facilities, hospitals, and electrical networks had been damaged, slowing rescue and aid efforts.

  ➤ early relief work was further complicated due to confusion over who was in charge and air traffic congestion.

  ➤ port au prince's morgues buried tens of thousands of bodies in mass graves.
• what were the long-term responses to the haiti earthquake?

  ➤ the EU gave $330M and world bank waived country's debt repayment for five years.

  ➤ the senegalese offered land in senegal to any haitians who wanted it.

  ➤ 6 months later, 98% of rubble still remained uncleared, blocking access to roads.

  ➤ 1.6M in relief camps of tents and tarps - no transitional housing built. no electricity, running water, or sewage disposal.

  ➤ 1 year later, 1M remained displaced.

  ➤ dominican republic, neighbouring haiti, accepted refuges.
• what is the GDP of japan and the caribbean?

  japan - $37 000 per capita.

  caribbean - $1200 per capita.
• what is the percentage of the population below the poverty line in japan and the caribbean?

  japan - 12%.

  caribbean - 82%.
• why do some people choose to live in hazardous areas?

  ➤ benefits of volcanic sites - ash and cooled lava contain main minerals, allowing fertile soil for crops.

  ➤ people in poverty may have no choice.

  ➤ geothermal energy - as the magma is closer to the surface at volcanic sites, the heat can be used for geothermal energy.

  ➤ modern technology that predicts natural hazards may comfort people.
• what are the four main methods of reducing risk from tectonic hazards?

  monitoring, prediction, protection, and planning.
• how can monitoring and prediction be used to reduce risk from tectonic hazards?

  ➤ seisometers monitor the intensity and frequency of seismic waves, producing seismographs to indicate earth movement.

  ➤ ground deformation often occurs due to movement of magma within crust. tilt of slope can be measured.

  ➤ gas sensing can detect sulphur dioxide (volcanoes) or radon gas (earthquakes).
• how can protection be used to reduce risk from tectonic hazards?

  ➤ volcanoes - evacuation and exclusion zones, moving people to safety.

  ➤ drills, enduring people know how to best protect themselves during a hazard.

  ➤ building design - steep latticework cages stabilise buildings, safe open areas for people to gather, latticework steel foundations build into bedrock, buildings made from reinforced concrete.
• how can planning be used to reduce risk from tectonic hazards?

  ➤ well-trained emergency services.

  ➤ risk assessment & hazard mapping to identify which areas are at greater risk so building can be restricted.

  ➤ evacuation plans.

  ➤ education.
• what is global atmospheric circulation?

  the movement of air across the planet in a specific pattern, driven by the equator as it receives the most direction sunlight and heats the air.
• what happens when air sinks towards the ground?

  creates area of high pressure.
• which direction does air move?

  from areas of high pressure to areas of low pressure.
• describe the movement of air in global atmospheric circulation

  1. the equator is the hottest as it receives the most direct sunlight (due to curvature and tilt). this causes air to rise, leading to low pressure and rainfall.

  2. when the air reaches the edge of the atmosphere, is cannot go further so travels north and south. the air becomes cold and sinks to create high pressure and dry conditions 30º N&S.

  3. air rises again at around 60º N&S. descends again at around 90º.
• what does global atmospheric circulation create?

  winds across the planet and areas of high rainfall and dry air.