Global Geographical issues: Hazards Flashcards

1
Q

What is the focus of an earthquake?

A

The centre of the earthquake beneath the earth. If it is close to the surface (shallow) then it will be a powerful earthquake and if it is deep then it will be weaker.

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2
Q

What is the epicentre of an earthquake?

A

The centre at the surface of the earth

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3
Q

What is the top layer of the earth called?

A

The crust (made from tectonic plates)

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4
Q

What is the second layer of the earth called?

A

Mantle- divided into solid upper mantle and partially liquid lower core

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5
Q

What is the centre of the earth called?

A

The core- divided into liquid outer core and solid inner core

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6
Q

What are the differences between the oceanic crust and the continental crust?

A
  • The oceanic crust is thinner due to being newer as it gets forced under the continental crust because it is denser
  • the oceanic crust is mainly made from basalt
  • The continental crust is thicker and less dense
  • the continental crust is mainly made from granite
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7
Q

What causes tectonic plate movement?

A

Plumes of heat called COLUMNS caused by RADIOACTIVE DECAY of materials like uranium rise to the surface to create CONVECTION CELLS in the mantle. These convection cells push together (DESTRUCTIVE PLATE BOUNDRIES) or pull apart (CONSTRUCTIVE PLATEBOUNDRIES) tectonic plates causing them to move in the direction of their flow. `

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8
Q

What is the name of the process by which the oceanic crust gets pushed under the continental crust?

A

Subduction

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9
Q

What is a conservative margin?

A

Theresa mays new policy or
When two tectonic plates slide past each
other. The friction between the two plates causes earthquakes. Sometimes the two plates get stuck and the tension builds up until it suddenly slips, releasing a huge earthquake and a lot of energy.

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10
Q

What type of destructive plate boundary creates mountain ranges?

A

Collision plate boundries- two continental plates of low density granite collide, pushing up into mountains.

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11
Q

What happens at constructive plate margins?

A

As plates move apart, basalt magma rises up through the middle forming lava flows an shallow sided volcanoes e.g. Iceland

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12
Q

What happens at a destructive margin?

A

Plates are pushed together but the oceanic plate is subducted.

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13
Q

What hazards are brought by tropical cyclones?

A
  • Strong winds-destroys vegetation and buildings
  • Storm surges bring powerful, fast flowing floods
  • intense rainfall-flooding-landslides
  • Landslides/mudslides caused by saturated ground.
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14
Q

How do tropical cyclones form?

A

Warm air rises(when temperatures exceed 26.5c) from the ocean and more is drawn in to replace it, then rising as well. Up draughts contain a lot of water vapour which condense into cumulonimbus clouds creating heat to power it further. Coriolis force causes rising air to spiral. This speeds up with new air as it moves but slows down once it reaches a landmass as there is not enough moisture it decays into a storm.

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15
Q

Where do tropical cyclones form?

A
  • in areas exceeding 26.5 c
  • strong winds high up in the troposphere
  • low pressure brought together by the itcz
  • Over the sea where there is moisture.
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16
Q

What are the two different types of volcanoes?

A

Shield volcanoes and composite volcanoes

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17
Q

What are shield volcanoes?

A
  • found along constructive plate boundaries
  • formed by eruptions of thin runny lava which flows along way before solidifying
  • gently sloping sides with a wide base
  • contain basaltic magma
  • erupt frequently but not violently
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18
Q

What are composite volcanoes?

A
  • found on destructive plate boundaries
  • formed by eruptions of lava and ash that don’t flow far
  • steep sides and a narrow base
  • andesitic magma which contain a lot of gas
  • erupt rarely but violently
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19
Q

How are building built to prevent damage from earthquakes?

A
  • Rubber or steel foundations to allow movement
  • strong framework
  • reinforced gas and water pipes
  • a band of concreate on the roof to stop walls falling apart
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20
Q

What is the saffir-simpson scale?

A

What is used to measure the intensity of hurricanes in America

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21
Q

What are the social, economic and environmental impacts of tropical cyclones?

A
  • destroys homes and business’s which also costs the government in taxes and support In rebuilding
  • people starve due to crops being destroyed
  • people become ill due to contaminated water sources which also costs in health care and loses taxes
  • damages vegetation and destroys habitats
  • loss of livestock, poo fuel, food, disease
  • rubbish flowing into the sea
22
Q

What techniques are used for protecting against cyclones? (think about +/-)

A
  • weather forecasting
  • satellite technology
  • warning systems
  • Evacuation procedures
  • storm surge defences
23
Q

Where is an example of successful evacuation in preparation of a hurricane?

A

Hurricane sandy in 2012

24
Q

What is the ITCZ?

A

The point at which two large cells of air converge. These cells consist of low pressure rising from the hotter land, cooling and sinking causing areas of high pressure.

25
Q

How does the ITCZ bring west Africa’s rainy season?

A

In July, African countries like mali are in their summer season so the land is hotter this means:

1) The hot land causes the air to rise and create an area low pressure
2) Further south over the sea, an area of cold, dense high pressure forms due to being cooler than land
3) wind blows from high to low pressure bringing moisture from the sea
4) Other winds blowing south towards west Africa bringing moisture from the sea
5) The two winds meet heat and rise to create tall cumulonimbus clouds as they call
6) heavy rain falls as the clouds condense

26
Q

What are the theories behind climate change?

A

The eruption theory
The sunspot theory
The orbital theory

27
Q

What is the volcanic eruption theory?

A

1) volcanic eruptions can change the earths climate
2) The blanket of ash and gas blocks out sunlight
3) this lowers the average temperature of the planet
4) If the ash and gas rises high enough, it enters the stratosphere and gets blown around the world by high winds
e. g. mount Pinatubo lowered the average temperature by 0.5’C

28
Q

What is the sunspot theory?

A

That when there are more sun spots, more solar energy is released and therefore heats the earth up more.

29
Q

What is the orbital theory?

A

The theory that global temperatures are affected by changes in the earths orbit changing shape ( circular to oval) and the earths axis wobbling and tilting, affecting how much solar energy reaches areas or earth.

30
Q

How do we know the earths climate was different in the past?

A
  • carbon samples from ice cores in Antarctica

- u-shaped valleys suggest glaciers formed in a colder climate as they would be v shaped

31
Q

What are the hazards brought by tropical cyclones?

A
  • intense rainfall
  • landslides
  • strong winds
  • storm surges (caused by low pressure and strong winds)
32
Q

Why are poor countries more likely to suffer from tropical cyclones?

A
  • poorly built houses
  • built on flood plains
  • poor evacuation plans and preparations
  • poor weather prediction technology
  • hard to spread the message without internet and tv
  • e.g. Bangladesh
33
Q

What is the thick continental crust made from?

A

Granite

34
Q

What is the thin oceanic crust made from?

A

basalt

35
Q

What are the layers of the earth called?

A
1 - crust
2 - upper mantle
3 - lower mantle (semi-molten)
4 - outer core (liquid)
5 - inner core (solid)
36
Q

What is heat in the earth caused by?

A

Radio active decay

37
Q

What is an example of a developing country which suffered from an earthquake?

A

Hati 2010,which lost 300,000 people

38
Q

What is an example of a developed country which suffered from an earthquake?

A

Japan 2012, lost 15,000

39
Q

What was the name of the cyclone which hit Bangladesh?

and what where the impacs?

A

cyclone aila

  • intense rain
  • wind
  • huge storm surge
  • 10 percent of Bangladesh below sea level
  • 200 dead
  • 750 000 homeless
  • 3 million affected
  • mangrove forest damaged
40
Q

What is a composite volcano?

A

A type of volcano found along destructive plate boundaries:

  • Formed by eruptions of viscous, sticky lava and ash that doesn’t flow far
  • steep sides and a narrow base
  • erupt infrequently but violently
41
Q

What is a shield volcano?

A

A type of volcano found along constructive plate boundaries:

  • Formed by eruptions of thin, runny lava which flows a long time before it solidifies
  • have gentle sloping sides with a wide base
  • erupt frequently but not violently
42
Q

What does the magnitude of an earthquake mean?

A

Strength of an earthquake

43
Q

What does ‘The Richter Scale’ measure?

A

The energy released in an earthquake

44
Q

How can scientists predict volcanic eruptions?

A
  • increase in gas emissions
  • increase in soil temperature
  • the volcano swelling`
45
Q

What were the primary impacts of the Hati earthquake in 2010

A
  • rubble and destroyed buildings
  • 316,000 dead
  • hospitals and mortuaries full
  • power lines down
  • 250,000 homes destroyed
46
Q

What were the impacts of the Icelandic eruption in Iceland?

A
  • giant ash clouds disrupting airports all over Europe

- ash fell, destroying crops

47
Q

How does the greenhouse effect works?

A

1) sun warms up the earths surface
2) some warmth radiates up from the surface and into the atmosphere
3) without greenhouse gases the warmth escapes back into space
4) With the greenhouse gases, some warmth is trapped, in the same way as the glass in a greenhouse traps warm air.
5) however due to increasing pollution, the greenhouse gases are trapping in too much heat, warming the earth.

48
Q

How do circulation cells influence Africa’s climate?

A

1) at the ITCZ, an area of low pressure is created as the hot air rises.
2) further south, the sea is still cool meaning the air above forms an area of high pressure.
3) trade winds blow from high to low pressure bringing moisture towards west Africa.
AND
1) Further north, the Mediterranean and Atlantic form areas of high pressure due to being cooler
2)Wind blows from high to low pressure bringing moisture
3) The two Hadley cells converge at the ITCZ and tall Columbus clouds from as the meet and fall as heavy rain.
AND
1) the Hadley cells also move the hot air which has risen at the ITCZ back north and south after it has deposited its moisture.
2) this means over north Africa, hot dry air blows from north to south creating the arid conditions of north Africa.

49
Q

HOw do we t=know the climate was different in the pass?

A
  • Carbon samples from ice cores; more carbon means a hotter climate.
  • V- shaped valleys haves been carved into U-shaped valleys by glaciers suggesting a colder climate.
50
Q

What are the possible consequences of climate change?

A
  • Drought causing economic loss and starvation
  • Increased rainfall causing flooding which affects…
  • Temperature rise causing increased sea-levels threatening coastal ecosystems and economies
  • Increased storminess so more risks from hurricanes
  • Unreliable rainfall thus stresses in agricultural systems -Desertification and thus impact on agricultural output with falling crop yields.
  • Climate change may allow a greater range of crops to be grown
  • hot temperatures allow for some diseases spreading easier impacting human lif