Unit B6 Managing Hazards

Revision cards for Unit B6 - Managing Hazards in 1312 Edexcel GCSE Geography A

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  • Created by: Roy F
  • Created on: 25-03-09 14:56

Types of Plate Boundaries

Types of Plate Boundaries

There are different types of plate boundaries:

Constructive Plate Boundary

  • Oceanic Crust - Oceanic Crust
  • Plates move AWAY from each other
  • Crust is FORMED

Destructive Plate Boundary

  • Continential Crust - Oceanic Crust
  • 2 Plates move towards each other
  • Oceanic Crust goes under Continental Crust
  • Crust is DESTROYED
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Plate Boundaries Cont.

Conservative Plate Boundary

  • 2 Plates Move side to side at different speeds or in opposite directions
  • No crust is created or destroyed
  • Earthquakes are common at these plate boundaries
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  • Power measured using RICHTER SCALE
  • Focus - Where plate collision occurs
  • Epicenter - Point on land directly ABOVE Focus

Earthquake-proof structures - buildings

  • Rolling wights on roof to counteract shock waves
  • Automatic shutters to prevent pedestrians below being showered with glass
  • Identification number visible for helicopters assessing damage after earthquake
  • 'Birdcage' interlocking steel frame
  • Reinforced lift shafts with tensioned cables
  • Panels of marble and glass flexibly anchored to steel superstructure
  • Open areas where people can assemble if evacuated
  • Reinforced latticework foundations deep in bedrock
  • Rubber shock-absorbers between foundations and superstructure
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Earthquakes cont...

Earthquake-proof structures - bridges

  • Steel cables attached to bridge girders and to columns to restrain movement
  • New concrete walls added between existing columns to make structrure more rigid
  • Concrete columns encased in steel jacket to keep concrete from crumbling when shaken by earthquake
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Tropical Storm LEDC Cyclone One Bravo

Cyclone One Bravo

Names to remember:

  • Areas most heavily affected: Chittagong, Cox's Bazaar and Teknaf
  • Made landfall near Chittagong on 19 May 1997
  • 111 people died, 7,000 injured

Impacts on People:

  • 111 people die, 7,000 injured
  • 500,000 left homeless
  • 608 educational institutions damaged
  • Ponds & wells contaminated by salt water - 1 million people with no access to fresh water.
  • Large number of fishing boats and nets were destroyed in towns along coast
  • Electricity supply disrupted - only partially restored after 1 week
  • Outbreaks of diarrhoea
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One Bravo Cont.

Impacts on environment

  • Crops destroyed in low-lying islands of Bay of Bengal
  • 30,000 hectares of crops damaged, 2,000 cattle were lost
  • Much of the year's rice harvest in storage was destroyed
  • Widespread destruction of infrastructure
  • Communication lines cut - difficult to receive damage & casualty reports

Influence of state development on impact

  • Earth embankments constructed along the coast
  • Cyclone shelters constructed above floodwater levels - approx. 1 million ppl used these
  • Education programmes for inhabitants about storm warnings
  • Poor families went to desperate lengths to save possessions - fear of them being stolen
  • Low tide, good visibility, ppl were better able to access emergency shelters
  • The Bangladesh Red Crescent had a cyclone preparedness programme
  • 15,000 volunteers in the area contributed to successful evacuation.
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One Bravo Cont..

Why people still live in these areas

  • Fertile area of Bangladesh
  • Good for growing of crops
  • 000s of ppl with no work/money if they moved away
  • Many people depend on fishing
  • Ppl cannot afford to move
  • They don't think it'll happen again
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Tropical Storms MEDC Hurricane Floyd

Hurricane Floyd


  • Made landfall on US mainland at Cape Fear, NC on 16 September 1999
  • Moved up the coast, weakening and dissipated near New England

Impact of storm on people

  • 79 deaths and 000s of injuries attributed to Floyd
  • 47 deaths in NC after 500mm of rain and flooded 30,000km squared
  • 4 million ppl evacuated in NC, SC, GA, FL
  • 1 million ppl - no electricity or water supplies
  • 4,000 ppl in PA left homeless
  • 42,973 homes damaged, 11,779 destroyed or heavily damaged
  • 14 states from FL to ME affected, NC most seriously hit
  • 25,000 Flood insurance claimants received tital of $460 million - benefits
  • 144,854 in 9 states registered for state & federal assistance
  • 10% crop was lost
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Hurricane Floyd Cont.

Impacts on environment

  • Storm surge caused a number of boats to be beached or sunk
  • Large areas of dunes and beaches were destroyed
  • Oak Island lost 20m of beach
  • Agricultural losses estimated at $1 billion

What was done to lessen impact

  • Good prediction and warning center by National Hurricane Center in Miami, FL
  • 2.5 people successfully evacuated
  • Evacuation effective - fatalities low
  • FEMA provides advice to families and businesses on how to protect themselves during hurricanes
  • US has building codes to construct hurricane-proof building
  • This includes storm shutters and shatter-resistant windows
  • Limited development allowed in areas of high risk from hurricanes - coastal zones
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Hurricane Floyd Cont..

Why do people still live in those areas

  • People have a full life with jobs & families
  • Well-insured
  • No worries about damage to property
  • Good warning systems
  • Help from FEMA providing disaster kits and plans
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