Natural Hazards Flashcards
(11 cards)
Define the term natural hazard
and natural disaster.
Hazards are unpredictable threats from the phycial, chemical and biotic environment.
A natural disaster is an event caused by natural forces , such as weather or geological activities that results in deaths ,injuries or serious property damage
When do disasters occur?
Diasters occur when a hazard causes deaths,injuries or serious property damages.
How can the risk be reduced that a hazard event lead to major disaster?
careful planning and a well organised response
Define the following:
earthquake
tsnumai
tornado
hurricane
an earthquake is the violent shaking of the ground
a tsnumai is a large powerful surging wave of water that can be 30m high
a tornado is a vortex of violently rotating winds, with wind speed over 300mph
a hurricane is a large system of low pressure bringing intense rainfall and high wind speeds
Define the following
an avalanche
landline
drought
volcanic eruptions
an avalanche is the rapid downward movement of a large quantity of snow and ice
a landline is the collapse of the earth from a cliif or a mountain
a drought is a prolonged period witn less rain than expected
a volcanic eruption is an opening in the Earth’s crust ,where magma reaches the surface as lava
State the four types of natural hazards and give three examples of each
Geophysical -Earthquakes ,Tsnumais and Landslides
Climatic -Hurricanes, cyclones and droughts(floods also)
Biotic -Plant disease ,Forest Fires(wild fire in Australia ) and Pests eg.locusts
Meotor impact - from space
Why are countries vulnerable to the 3 main categories of natural hazard?
1.They are close to plate margins which are risk zones for earthquakes and volcanoes
2.The islands and Central America are at risk from hurricanes because of location
3.Many people live in hazardous areas ;close to the sea ,on river flood plains ,or on steep sloopes
4.Humans have altered the Caribbean environment,increasing disaster risk as a result of removing Forest and Coastal Mangroves.
Compare disaster risks in the poorest countries.
In the poorest countries :
Lives are at risk
Many buildings are badly constructed.Building are placed on risky sites
There may be no building code
Many people have no insurance cover
Compare disaster in the richer countries
In the richer countries
Financial costs are greater,because more costly structures have beenbuilt
Most building are well constructured .Regulations restrict buildings on risky sites
There is usually a strict building code
many risks are insured