Hazardous Environments Flashcards
1
Q
hazard
A
event that threatens or causes damage and destruction to people, their property and settlements
2
Q
why are some places more hazardous than others? (4)
A
- some expereince more than one type of hazard
- some experience natural hazards more frequently than others
- in some places the hazards are stronger and more destructive than in others
- some places are better able to cope with the damaging impacts of natural hazards
3
Q
examples of geological hazards (3)
A
- earthquakes
- volcanic eruptions
- landslides
4
Q
examples of climatic hazards (3)
A
- storms
- floods
- drought
5
Q
examples of biological hazards (3)
A
- fires
- pests
- disease
6
Q
examples of technological hazards (3)
A
- nuclear explosion
- transport accidents
- pollution
7
Q
conditions needed for the development of a tropical cyclone (5)
A
- a deep layer of humid, warm and unstable air
- supply of energy (heat and moisture) from the surface of the sea
- sea must be at its warmest
- there must be circulatory motion of the air, this is encouraged by the coriolis force
- small changes in wind speed and direction with increasing altitude encourages the circulatory motion within the cyclone
8
Q
how does a tropical cyclone form (3)
A
- when high temperatures cause air to rise from the surface of the sea
- the rising air causes thunderstorms
- sometimes these small storms come together and create a strong flow of warm, rapidly rising air, which produces an area of increasingly low pressure
9
Q
coriolis force
A
the force created by the earth’s rotation that deflects any object moving at the earth’s surface
10
Q
how is cyclone built up? (3)
A
- rotating and vigorous upward spiral of humid, warm air
- in the eye (centre) there is an area of sinking air with calm conditions and clear skies
- surrounding eye is eye wall, where the most destructive energy occurs
11
Q
characteristics of tropical cyclone (6)
A
- areas of very low pressure
- bring torrential rain, thunder and lightning and very strong winds
- they follow the direction of the prevailing winds and ocean currents
- the further it travels over the sea, the more energy it gathers from contact with the warm ocean water, which increases its strength
- when it reaches land the supply of energy is cut off, it loses strength and moves more slowly
- average duration= 10 days
12
Q
tectonic plates (2)
A
- a rigid segment of the earth’s crust which can float across the heavier, semi molten rocks below
- they are constantly moving
13
Q
constructive or divergent plate margin
A
the margin between two plates that MOVE APART
14
Q
destructive or convergent plate margin
A
the margin between two plates that are moving TOWARDS EACHOTHER
15
Q
subduction (3)
A
- when the edge of a plate margin is being destroyed as it plunges beneath the other plate that is meeting it head on.
- molten rocks rise to the surface to form volcanoes
- the friction between plates causes earthquakes
16
Q
collision plate margin (2)
A
- occurs where two plates meet head on and are of equal density and strenth
- the sediment between the two plates is squeezed upwards and forms mountains and earthquakes
17
Q
conservative plate margin
A
occurs when two plates are sliding past eachother, the friction can make earthquakes
18
Q
hotspots (2)
A
- locations beneath the earth’s crust where strong and rising currents of magma occur
- when the crust above is weak, volcanos occur
19
Q
where do volcanoes and earthquakes occur?
A
along tectonic plate boundaries
20
Q
different forms of volcanic eruption (3)
A
- lava flows
- ash
- gas emission
21
Q
lava flows
A
do not cause that much death, because they only reach about 10 km.
22
Q
ash (4)
A
- can be thrown into air during a violent eruption
- carried in wind, so affects a large area
- ash causes damage because it covers everything, roofs can collapse etc.
- air thick with ash can asphyxiate people and animals
23
Q
gas emission (2)
A
- sulphur gases, carbon dioxide and cyanide can kill
- because they are dense, they stay close to the ground
24
Q
characteristics of earthquakes (4)
A
- centre of earthquake underground is called focus
- shock waves travel outwards from the focus
- strongest close to the epicenter
- aftereffect of earthquake is tidal wave or tsunami
25
epicenter
point on the surface directly above the focus
26
damage from earthquakes (3)
- damage depends on depth of focus and type of rock
- worst damage occurs where focus is closest to surface and where the rock is soft
- shake buildings, causing them to collapse, can cause fire
27
Volcanic Explosivity Index (VEI) (2)
- measures the intensity on a scale of 1 to 8
- explosivity is measured in terms of ash ejected and the height it reaches
28
limitations to VEI
- ash is not the main product of all volcanic eruptions, so only suited for one type of volcanic eruption
29
different types of scales for measuring earthquakes (3)
- richter scale
- mercalli scale
- moment magnitude scale (MMS)
30
Richter Scale (3)
- measures an earthquakes strength according to the amount of energy released during event
- energy is measured by a seismograph
- runs from 2.4- 8 or more
31
Mercalli Scale
based on what people experience and the amount of damage done
32
Moment Magnitude Scale (MMS) (3)
- most commonly used method
- measures energy released on a logorithmic scale
- the assesment of energy is based on the amount of rock movement along the fault or fracture and the area of the fault or fracture surface
33
Factors that affect amount of damage from natural disaster (6)
- size of area affected
- density of populationin affected area
- how long it lasts
- degree to which people are warned beforehand
- the degree to which people are prepared
- ability of country or region to deal with aftermath
34
primary imacts of earthquakes (3)
- collapsed buildings, and the people killed by them
- broken water, gas and sewage pipelines
- downed electric power lines
35
secondary impacts of earthquakes (3)
- tsunamis
- aftershocks
- fires due to ruptured gas mains
36
primary impacts of volcanic eruptions (3)
- buildings, rodas etc destroyed by lava flows
- death and injuries resulting directly from lava, ash and gas
- contamination of water supplies from ash
37
secondary impacts of volcanic eruptions (3)
- lahars created by the mixing of volcanic ash and mud with rainwater
- fires started by lava and pyroclastic flows
- psychological trauma
