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Global Geography 12
Reading Guide Natural Disasters pages 76 - 80
1. Suggest two reasons why people can’t or refuse to move away from areas
with frequent natural disasters.
2. Define:
Natural Hazard
Natural Disaster
3. What are the consequences of disasters in areas with high populations?
4. What makes disasters worse for people in LDCs?
5. In your own words, define the following terms:
Frequency
Duration
Extent
Speed of Onset
Spatial Dispersion
Temporal Spacing
6. What is the most common way to compare natural disasters?
7. How are hurricanes measured?
8. How are earthquakes measured?
9. What types of disasters affect the greatest number of people?
10. What types of disasters cause the most deaths?
11. What type of disaster causes a large number of deaths in a relatively small
area?
Classifying
Natural Disasters
Global Geography 12
Reading Guide Atmospheric Hazards pages 81 – 85
What are atmospheric hazards?
What causes front storms?
When two air masses are very different, what is the result?
What unusual condition caused the Great Ice Storm of 1998?
How long did the freezing rain last?
What kinds of damage were caused by the ice?
Describe how people were affected by the storm.
What conditions are needed for tropical cyclones to develop?
What are two other names for tropical cyclones?
How many deaths are caused by tropical cyclones in an average year?
Where do tropical cyclones form?
What are the two reasons that theses storms cause damage?
What problems occur even after the storm has stopped?
What is a tornado?
Where do tornadoes form?
What two conditions are needed for a tornado to form?
Why do hurricanes cause more deaths, even though tornadoes have higher
wind speeds?
What causes most floods?
What kind of rivers is most likely to flood?
What causes seasonal flooding?
Define storm surge.
What are droughts?
What is the almost inevitable effect of drought?
What makes drought one of the most important types of natural disaster?
What are three long term effects of drought?
Earthquakes
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Most violent and sudden of the geologic disasters
Occur most often along the edge of tectonic plates
Most deaths and injuries occur because of buildings collapsing
Afterward, injured people may die due to lack of medical aid, food,
water and shelter, as well as fires or disease
Earthquakes cause more damage and deaths in LDCs because
o cities are more crowded (high population density)
o lower building standards
o no plans or few services ready for disaster relief
o less money for disaster relief
Volcanoes
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Volcanoes cause fewer deaths than many other natural disasters.
Generally some activity (earth trembles, smoke, ash) occurs before an
eruption to warn people to leave.
Sometimes the eruption is violent and sudden – these eruptions are the
most dangerous.
Most deaths in sudden eruptions are caused by pyroclastic flow – clouds
of superheated gas.
Deaths afterward occur due to fires started by the eruption or famine due
to loss of crops.
Damage due to large amounts of ash and cinders, fires, or lava flows.
Can cause world-wide effects: cooler weather and acid rain.
The heat of volcanic activity (geothermal energy) can be used to provide
electricity and heat (Iceland does this.)
Landslides
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Occur in areas where natural slopes exist (river valleys, hills, mountains).
May be called rockslides, landslides, mudslides, etc.
A “triggering event” causes rock or soil to move rapidly down the
slope.
Triggering events can include:
o earthquakes
o heavy rainfall
o loss of natural vegetation (plant and forest cover)
o mining or road construction
Damage property and structure by fast speed of movement and
weight of soil or rock.
Deaths caused by being buried or crushed.
Avalanches
 Occur where snow and ice accumulate on slopes.
 Can be triggered by human activity or natural causes, such as
temperature change.
 Are less frequent and affect smaller areas than other types of slides.
Tsunamis
 Tsunamis are caused by slides, earthquakes or
volcanoes on the ocean floor.
 Waves do not seem very large on the open water,
but the height increases as they approach land.
 Waves up to 30m high and speeds over 200 km/hour
http://gsc.nrcan.gc.ca/volcanoes/images/fig31_e.gif
Landslides
http://www.satimagingcorp.com/media/images/natural-hazards-5.jpg
www.indiana.edu/~pepp/earthquakes/images/sumatra12_26_04/tsunami_traveltime_local.jpeg
Tsunami (at the coast)
Propagation
Generation (occurs offshore)
http://users.skynet.be/envirconsult/tsunami/propagation_tsunami.gif