Hazardous Environments

Question 1

hazard

Answer 1

event that threatens or causes damage and destruction to people, their property and settlements

Question 2

why are some places more hazardous than others? (4)

Answer 2

• 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

Question 3

examples of geological hazards (3)

Answer 3

• earthquakes
• volcanic eruptions
• landslides

Question 4

examples of climatic hazards (3)

Answer 4

• storms
• floods
• drought

Question 5

examples of biological hazards (3)

Answer 5

• fires
• pests
• disease

Question 6

examples of technological hazards (3)

Answer 6

• nuclear explosion
• transport accidents
• pollution

Question 7

conditions needed for the development of a tropical cyclone (5)

Answer 7

• 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

Question 8

how does a tropical cyclone form (3)

Answer 8

• 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

Question 9

coriolis force

Answer 9

the force created by the earth’s rotation that deflects any object moving at the earth’s surface

Question 10

how is cyclone built up? (3)

Answer 10

• 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

Question 11

characteristics of tropical cyclone (6)

Answer 11

• 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

Question 12

tectonic plates (2)

Answer 12

• a rigid segment of the earth’s crust which can float across the heavier, semi molten rocks below
• they are constantly moving

Question 13

constructive or divergent plate margin

Answer 13

the margin between two plates that MOVE APART

Question 14

destructive or convergent plate margin

Answer 14

the margin between two plates that are moving TOWARDS EACHOTHER

Question 15

subduction (3)

Answer 15

• 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

Question 16

collision plate margin (2)

Answer 16

• 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

Question 17

conservative plate margin

Answer 17

occurs when two plates are sliding past eachother, the friction can make earthquakes

Question 18

hotspots (2)

Answer 18

• locations beneath the earth’s crust where strong and rising currents of magma occur
• when the crust above is weak, volcanos occur

Question 19

where do volcanoes and earthquakes occur?

Answer 19

along tectonic plate boundaries

Question 20

different forms of volcanic eruption (3)

Answer 20

• lava flows
• ash
• gas emission

Question 21

lava flows

Answer 21

do not cause that much death, because they only reach about 10 km.

Question 22

ash (4)

Answer 22

• 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

Question 23

gas emission (2)

Answer 23

• sulphur gases, carbon dioxide and cyanide can kill
• because they are dense, they stay close to the ground

Question 24

characteristics of earthquakes (4)

Answer 24

• 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

Question 25

epicenter

Answer 25

point on the surface directly above the focus

Question 26

damage from earthquakes (3)

Answer 26

- 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

Question 27

Volcanic Explosivity Index (VEI) (2)

Answer 27

- measures the intensity on a scale of 1 to 8 - explosivity is measured in terms of ash ejected and the height it reaches

Question 28

limitations to VEI

Answer 28

- ash is not the main product of all volcanic eruptions, so only suited for one type of volcanic eruption

Question 29

different types of scales for measuring earthquakes (3)

Answer 29

- richter scale - mercalli scale - moment magnitude scale (MMS)

Question 30

Richter Scale (3)

Answer 30

- 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

Question 31

Mercalli Scale

Answer 31

based on what people experience and the amount of damage done

Question 32

Moment Magnitude Scale (MMS) (3)

Answer 32

- 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

Question 33

Factors that affect amount of damage from natural disaster (6)

Answer 33

- 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

Question 34

primary imacts of earthquakes (3)

Answer 34

- collapsed buildings, and the people killed by them - broken water, gas and sewage pipelines - downed electric power lines

Question 35

secondary impacts of earthquakes (3)

Answer 35

- tsunamis - aftershocks - fires due to ruptured gas mains

Question 36

primary impacts of volcanic eruptions (3)

Answer 36

- buildings, rodas etc destroyed by lava flows - death and injuries resulting directly from lava, ash and gas - contamination of water supplies from ash

Question 37

secondary impacts of volcanic eruptions (3)

Answer 37

- lahars created by the mixing of volcanic ash and mud with rainwater - fires started by lava and pyroclastic flows - psychological trauma