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Geography OCR B GCSE > Global Hazards > Flashcards

Global Hazards Flashcards

REMEMBER TO ADD BOSCASTLE AND BIG DRY AFTER JAN

1
Q

What happens at the equator in terms of atmospheric circulation?

A

Two converging air masses meet(both hadley cells) and rise, forming a low pressure system and creating heavy rainfall at the equator.

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2
Q

What happens at:
1. 30N
2. 30S
3. 60N
4. 60S

A
  1. High pressure system(Hadley+Ferrel)
  2. High pressure system(Hadley+Ferrel)
  3. Low pressure system(Ferrel+Polar)
  4. Low pressure system(Ferrel+Polar)
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3
Q

What determines heat? Why? [2]

A
  • Latitude; because of insolation
  • Sun’s rays are concentrated at the equator, as opposed to spread out at higher points and lower points.
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4
Q

What determines dryness? Why? [3]

A
  • Pressure belt
  • High pressure belt means low precipitation
  • Low pressure belt means high precipitation
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5
Q

What are Westerlies? What are Trade Winds?

A
  • Westerlies are winds that blow towards the poles.
  • Trade winds are winds that blow towards the equator.
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6
Q

What are the 4 climate zones?

A
  • Polar; cold all year round
  • Tropical; High temperatures all year round and high precipitation
  • Temperate; Moderate summers and winters
  • Arid; hot/warm and dry
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7
Q

What are the coldest and hottest temperatures ever recorded and where were they?

A
  • Coldest was in Antarctica(-89.2C) due to insolation and ice albedo
  • Hottest was in Death Valley (56.7C) due to high pressure system and insolation
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8
Q

What weather extremes are associated with wind? [3]

A
  • Trade Winds
  • Katabatic winds(up to 320km/hr of wind flowing downhill)
  • Jet streams(winds very high up in the atmosphere)
  • Tornadoes(strong rotating winds) or tropical storms, causing house destruction
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9
Q

What weather extremes are associated with temperature?[3]

A
  • Latitude(insolation)
  • High pressure systems have less cloud cover as the air is sinking, so less light is blocked by clouds, so it’s hotter.
  • Ice albedo also lowers temperature
  • Ocean currents also carry more heat easily, so they have a warming effect.
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10
Q

What weather extremes are associated with precipitation? [3]

A
  • Precipitation is much higher low pressure belts, so it is affected by rainfall
  • Frontal: Warm air rises over cool air, cools and condenses, and precipitates
  • Convectional: Air from sea rises, expands, cools, condenses, and precipitates
  • Relief: Air is forced to rise over land, and condenses and precipitates
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11
Q

What is the distribution of tropical storms? [2]

A
  • A lot of tropical storms occur in East Asia in late summer and Autumn
  • NO TROPICAL STORMS ON EQUATOR
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12
Q

What is the frequency of tropical storms? Why? [2]

A
  • 2007 found increase in observed hurricanes over the past century, but no overall trend
  • Likely due to increased technology so more can be picked up
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13
Q

What is the distribution of droughts? [2]

A
  • Typically affected by rainfall and demand for area; High pressure areas get more frequent droughts
  • More in Africa, Asia, and the Mediterranean
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14
Q

What is the frequency of droughts?

A
  • Predicted persistent droughts in next 50 years, and Climate Change + Global Warming will increase temperature
  • Therefore higher chance of droughts, but currently varied frequency per year.
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15
Q

How are tropical storms formed? [5]

A
  • They form between 5-15N and S of the equator, when sea temperature is above 27C
  • Warm ocean means there is a lot of moist air, so it rises, cools, and condenses into droplets, forming huge cumulonimbus clouds.
  • These droplets combine to fall as rain
  • Since the air has risen in the center, there is a low pressure system in the middle, causing high pressure areas to be pushed into it by trade winds
  • This forms high speed rotating winds due to Earth’s rotation(Coriolis effect)
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16
Q

How can tropical storms cause damage? [3]

A
  • Fast strong winds can launch projectiles into buildings, kill people, damage infrastructure, and block roads
  • Storm surges; wind blows water over land, so huge waves and flooding is caused
  • Large amounts of rain, which can cause flash floods, destroy crops
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17
Q

What is El Nino? [4]

A
  • Warm water moves East due to weak trade winds, evaporating as it moves to SA
  • This warm air rises above SA, forming a low pressure system there with lots of rainfall.
  • Air then moves westwards via high altitude flow and sinks above Australia
  • This forms a high pressure system there, with warm, dry conditions, causing droughts and fires
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18
Q

What is La Nina? [4]

A
  • Very strong trade winds push water westwards towards the East Coast of Australia
  • This forms a high pressure system in Australia, so air rises and cools and condenses there, causing flooding and extreme conditions of a normal year
  • Air then moves eastwards via a high altitude flow, and sinks above South America
  • This forms a high pressure system there and causes extreme weather conditions like droughts and fires there
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19
Q

What are the 4 layers of the Earth?

A
  • Crust: can be Oceanic(dense, thin, made of basalt, 8km), or continental(less dense, thin, made of granite, 35km)
  • Mantle(up to 4000C)
  • Outer core(up to 6000C)
  • Inner core(7200C)
20
Q

What are convection currents and what do they affect? [2]

A
  • The lower parts of the mantle are hotter than the upper parts, when they heat up, they become less dense, rise, cool, and sink in circular movements called convection currents.
  • These cause tectonic plates to move
21
Q

What is a destructive plate boundary? [5]

A
  • When an oceanic plate meets a continental plate, the more dense oceanic plate sinks under the continental plate
  • It then goes into the mantle, where it is subducted(sinks into the subduction zone) and destroyed
  • Forms trenches, which can cause violent earthquakes if the plates get stuck
  • Forms composite volcanoes
  • Example: Tohoku Earthquake, Japan
22
Q

What is a conservative plate boundary? [4]

A
  • Two plates moving sideways past each other, and the jagged edges get caught due to friction
  • Pressure builds up, so when they jolt, it is all released
  • Causes earthquakes
  • Example: San Andreas Fault OR HAITI EARTHQUAKE
23
Q

What is a collision plate boundary? [4]

A
  • 2 continental plate boundaries move towards each other, and collide
  • Neither is forced below the other, so they are both forced upwards
  • Creates fold mountains
  • Example: Himalayas
24
Q

What is a constructive plate boundary? [4]

A
  • 2 plates move apart, so magma rises to fill the gap
  • This magma cools and forms new crust
  • Forms shield volcanoes
  • Example: Eyjafjallajokull
25
Q

What are hotspots? [4]

A
  • Hotspots come from mantle plumes originating in the outer core, coming from heat from subducted rock
  • These rise up and form volcanoes by hitting the surface of the crust
  • As the tectonic plate moves, it drags the plume head, forming volcanoes as it goes along
  • These are known as volcanic chains(Like the Hawaii volcano chain)
26
Q

How does tectonic plate movement cause Earthquakes? [2]

A
  • Energy is released into the focus from built-up pressure, releasing seismic waves
  • These waves reach the surface at the epicentre.
27
Q

What two types of Earthquakes are there? Where do they each occur?[4]

A
  • Deep focus(70-700km below surface),rarer, which cause less damage as it spreads vertically
  • Occur on destructive plate boundaries as they are triggered when the oceanic plate sinks
  • Shallow focus(less than 70km below surface),more common, cause more damage as it is closer to the surface(so over smaller area)
  • Occur on collision and conservative plate boundaries
28
Q

How does tectonic plate movement cause volcanoes? [2]

A
  • Partially melted mantle is viscous, and rises.
  • It contains hot gases which build up pressure, so when it is released it erupts violently and cools quickly, forming steep volcanoes
29
Q

What are the characteristics of composite volcanoes? [5]

A
  • Acid, viscous lava
  • Rare eruptions
  • Violent eruptions
  • Occur at destructive plate boundaries
  • Cone-shaped/steeper
  • Thinner layers of ash and lava(which sometimes forms a plug at the top of the volcano, building up enormous pressure, making the eruption even more explosive
30
Q

What are the characteristics of shield volcanoes? [5]

A
  • Basic, runny lava
  • Frequent eruptions
  • Gentler eruptions
  • Occurs on conservative plate boundaries or hotspots
  • Shallower/flatter
  • Thicker layers
30
Q

Name 3 ways technological developments can save lives in hazard zones.

A
  • Early warning systems; people in Japan had 30 seconds to prepare, turn off utilities to avoid fires and leaks, find cover, stop delicate activities, etc.
  • Computer controlled roof weights, cross-bracing to prevent twisting in buildings, shutters to prevent falling glass
  • Seismometers and lasers to predict indications that an earthquake is likely
  • Go-bags for preparation, education on earthquake safety
31
Q

What are the details of the Haiti Earthquake? [3]

(Name the focus, magnitude, and date)

A
  • 10-13km deep focus
  • 7.0 on the Richter Scale magnitude
  • 12th January 2010
32
Q

What caused the Haiti Earthquake?

A

A conservative plate boundary between the Caribbean and North American plate.

33
Q

What were the primary effects of the Haiti Earthquake? [4]

A
  • 220,000 deaths
  • Power lines cut, so no communications
  • 106,000 homes destroyed(as builders took shortcuts)
  • 80% of schools destroyed
  • Damage to airport runways made it hard to transport aid
  • Prison collapse led to escaped prisoners
34
Q

What were the secondary effects of the Haiti Earthquake? [4]

A
  • 2 million Haitians left without water(social)
  • November 2010 Cholera outbreak(social)
  • Stealing became an issue(social)
  • Up to $8.5billion in damages(economic)
  • 8 hospitals destroyed; INTENSE overcrowding in hospitals(social)
35
Q

What were the immediate responses to the Haiti Earthquake? [3]

A
  • Medecins Sans Frontieres sent to Haiti
  • UN Search and Rescue teams saved 120 people in the following week of the Earthquake
  • 10,000 NGOs involved: BAD because it was too disorganised and chaotic to provide efficient help
  • World Food program sent food in planes, trucks
36
Q

What were the long-term responses to the Haiti Earthquake? [4]

A
  • Public donations endorsed by celebrities
  • International Goverment aid pledges, like Florida Search and Rescue teams sent. and money to rebuild
  • World Food Program sent food in planes, trucks(long-term because it went on for months)
  • Earthquake drills and training provided to educate the population
  • Cash for Work programs paying Haitians to clear rubble
37
Q

When was the Boscastle flood?

A

16th August 2004

38
Q

What where the place specific causes of the Boscastle flood? [2]

A
  • Boscastle is in the Valency Valley, which is steep sided. It is also located on the confluence of 3 rivers (Paradise, Jordan and Valency), making it very prone to flooding
  • Boscastle was built around impermeable rock such as slate and clay, which meant that much less rain was absorbed into the soil, so flooding was more likely.
  • Boscastle also experienced heavy rain prior to the event, which meant that the ground was saturated and could carry less water. Knock-on effect to the impermeable rock point.
39
Q

What were the impacts of the Boscastle flood? [4]

A
  • 1000 residents and tourists affected
  • 58 properties damaged, 6 completely destroyed
  • Cost £2 million
  • Damaged 25 of Boscastle’s businesses
  • Destroyed tourism in Boscastle; 90% of it’s income is from tourism
  • 4 bridges destroyed and washed away
  • Trees uprooted and washed away
40
Q

What were the immediate responses to the Boscastle flood? [3]

A
  • Over 150 people airlifted to safety by 7 RAF helicopters.
  • Police, Fire Brigade, and Coast Guard responded in minutes
  • Temporary shelters put up for those evacuated
  • Nationwide media coverage
41
Q

What were the long-term responses to the Boscastle Flood? [3]

A
  • River Jordan Channel Relief made wider
  • 1850 tonnes of silt and debris cleared
  • River banks and flood walls were raised
  • New technology to help predict flood events more accurately
  • £4.5 million dedicated to a flood prevention scheme
42
Q

What were the causes of the Big Dry in Australia(2005-2008)? [2]

A
  • High pressure system above Central Australia
  • Australia is a large, relatively flat continent - moisture doesn’t penetrate deep into the interior
  • Mainly caused by a strong El Nino year.
43
Q

What were the social impacts of the Big Dry in Australia? [3]

A
  • 13 dairy farms closed(only 6 survived)
  • Water shortage led to a drop in agricultural production
  • Rural areas had no water
  • Rural suicide rate soared
  • Mass migration into wetter areas
44
Q

What were the economic impacts of the Big Dry in Australia? [2]

A
  • Farmers had to sell water and cattle because they couldn’t afford to feed them
  • Wheat production and exports dropped by 46%
  • Food prices increased because Australia had to rely on imports
  • Energy and water prices increased by 20%
45
Q

What were the environmental impacts of the Big Dry in Australia? [3]

A
  • River Murray dried up in places and was 50% below its normal level
  • Grassland transformed to shrubland due to water starvation
  • 70% of redgums died
  • 6 million sheep died
  • Drop in water levels meant less Hydroelectric power production, so coal had to be re-used for energy
  • Loss of vegetation, wildlife, biodiversity, as well as more soil erosion and salinisation.
46
Q

What were the responses to the Big Dry in Australia? [3]

A
  • Government dedicated $10 billion to national water management scheme in 2007
  • Government tried to control water usage more by introducing the national water database, which monitors water usage
  • Drought resistant crops introduced
  • Degraded and salt-affected areas were classified as retired to avoid additional water waste
  • Irrigation methods updated to avoid over-watering

Geography OCR B GCSE (9 decks)

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