Hazards

Question 1

definition

Hazard

Answer 1

Potential threat to human life and property caused by an event

Question 2

Three major types of geographical hazards?

Answer 2

geophysical, atmospheric, hydrological

Question 3

Geophysical hazard

Answer 3

Hazards caused by land processes mainly tectonic plates e.g. volcanoes

Question 4

Atmospheric hazards

Answer 4

Hazards caused by atmospheric processes and conditions created because of these such as weather systems e.g. wildfires

Question 5

Hydrological hazards

Answer 5

Hazards caused by water bodies and movements
e.g. floods

Question 6

Hazard Perception

Answer 6

One’s viewpoint of how dangerous a hazard is and what risk they pose.

Varies depending on lifestyle factors
e.g. economic and cultural factors

Question 7

Prediction

Answer 7

Using scientific research and past events in order to know when a hazard will take place so that warning may be delivered and impacts of the hazard reduced or even prevented.

Question 8

Adaptation

Answer 8

Attempting to live with hazards by adjusting lifestyle choices so that vulnerability to hazards is lessened.

Question 9

Mitigation

Answer 9

Strategies carried out to lessen the severity of a hazard.

Question 10

Management

Answer 10

Coordinated strategies to reduce a hazard’s effect, this includes prediction, adaptation, mitigation.

Question 11

Risk Sharing

Answer 11

A form of community preparedness, whereby the community shares the risk posed and invest collectively to mitigate the impacts of future hazards.

Question 12

The Park Model

Answer 12

Graphical representation of human responses to hazards. It shows the steps carried out in recovery after a hazard giving a rough indication of time frame.

Question 13

Stages of the Park Model

Answer 13

Stage 1 (hours/days): Relief - Immediate local response, medical aid, search/rescue.

Stage 2 (days/weeks): Rehabilitation - Services begin to be restored, temporary shelters/hospitals, foreign aid.

Stage 3 (weeks/years): Reconstruction - Restoring the area to the same or better. Infrastructure rebuilt. Mitigation strategies.

Question 14

Stages of the Hazard Management Cycle

Answer 14

Preparedness, Response, Recovery, Mitigation

Question 15

Evaluate the Models
(Park Model and Hazard Mangement Cycle)

Answer 15

Both models do not take into account the socio-economic development of the region.

Vague in time frame

Question 16

Plate tectonic theory

Answer 16

The lithosphere is broken into large slabs of rock called tectonic plates. The plates move due to convection currents in the atmosphere which push and pull the plates in different directions.
Convection currents occur when less dense magma rises, cools then sinks. the edges are plate margins.

Question 17

Constructive plate boundaries

Answer 17

Plates pull apart
Oceanic: New land forms (sea floor spreading)
Continental: Rift valley (Graben)

Question 17

Destructive plate boundary

Answer 17

Plates move toward eachother
Continental/Oceanic: ocean trench, fold mountains, composite volcanoes.
Oceanic: ocean trench, fold mountains, volcanoes, island arcs
Continental: fold mountains

Question 18

Ridge Push

Answer 18

The slope created when plates move apart has gravity acting upon it as it is at a higher elevation. Gravity pushes the plates further away, widening the gap (gravitational sliding).

Question 19

Slab pull

Answer 19

When the plate subducts, the plate sinking into the mantle also pulls the rest of the plate with it causing further subduction.

Question 20

Conservative plate boundary

Answer 20

The parallel move in different directions or at different speeds no landforms are created but fault lines can occur

Question 21

Hotspots

Answer 21

Areas of volcanic activity that are not related to plate boundaries. Hot magma plumes burn and rise through the weaker parts of the crust which can create volcanoes and islands.

The plume stay in one place but the plates continue to move which can create a chain of islands like Hawaii

Question 22

Volcanic hazards

Answer 22

Lava flows, Lahar, Tephra, Toxic gases, Acid rain, Nuees Ardentes/ Pyroclastic flows.

Question 23

Lava flows

Answer 23

Lava can flow quickly or slowly depending on its viscosity

Question 24

Lahars

Answer 24

caused by melting ice at high latitudes

Question 25

Tephra

Answer 25

Rock/ sediment ejected by a volcano

Question 26

Nuees Ardentes/ Pyroclastic flows

Answer 26

Clouds of burning hot ash and gas that collapses down a volcano at high speeds averaging at 60mph but can go as fast as 430mph

Question 27

Ring of fire

Answer 27

An area of high volcanic and earthquake activity located in the Pacific

Question 28

Seismic Hazards

Answer 28

Shockwaves, Tsunamis, Liquefaction

Question 29

Shockwaves

Answer 29

When two plate slide against each other it causes friction and pressure builds up. When the pressure becomes too much, the plates eventually move. The energy is released and vibrates through the ground.

Question 30

Tsunami

Answer 30

An earthquake jolts the ocean floor, displacing water upwards. This sets off an oscillation which develops under water at great speeds. Sea water is sucked back in from the shore. Waves get bigger as water gets shallower.

Question 31

Liquefaction

Answer 31

When soil is saturated the vibrations of an earthquake cause it to act like a liquid. Soil becomes weaker when it has large weight on it. causing landslides and avalanches.

Question 32

# definition Tropical storm

Answer 32

A low pressure spinning storm with high winds and torrential rain.

Question 33

Conditions for a tropical storm to develop?

Answer 33

Temperature, air pressure, wind, rotation and a trigger

Question 34

Temperature for tropical storm

Answer 34

Ocean temperatures must be around 27°C and at least 50m deep (it provides the storm with energy)

Question 35

Air pressure for Tropical storm

Answer 35

Must be in area of unstable air pressure (where high and low meet -convergence) so that warm air rises (as its less dense than cold) more steadily and clouds can form (air must be humid).

Question 36

Wind needed for Tropical storm

Answer 36

Winds must be present for swirling motion to form but not too strong or the storm system will be ripped apart in early stages.

Question 37

Rotation need for Tropical storm

Answer 37

TS only form around the equator, no less than 5° on either side. Requires the coriolis effect which is not at the equator - thats why it forms at certain distances away from it.

Question 38

Formation of a Tropical Storm

Answer 38

1. Warm moist air rises leaving an area of low pressure below. surrounding warm air moves into the area of low pressure and rises too. 2. The warm air then cools, condensing into thunderstorm clouds. 3. The system spins due to the coriolis effect. In the southern hemisphere the storm spins clockwise, in the northern anti clockwise 4. The constant additions of energy from the warm air cause the storm to spin faster and generate high wind speeds. At 39MPH it can be classified a TS. 5. The eye of the storm is in the centre, around 30m miles wide, with extremely low pressure, the more intense the storm the clearer the eye. 6. Surrounding the eye is the eyewall, most intense and powerful area of the storm. when wind reach 74MPH= Hurricane.

Question 39

What happens when a storm reaches a coast?

Answer 39

The low pressure and high winds will cause a large amount of sea water to be taken into the system and released as a high wave called a storm surge.

Question 40

What happens when a storm reaches land?

Answer 40

It no longer has a supply of energy and the eye eventually collapses - rain can continue on for days.

Question 41

Hazards caused by tropical storms

Answer 41

High winds: over 300km/h, can blow debris at high speeds. Flooding: coastal river flooding from storm surges and heavy rain Landslides: due to soil getting heavy Storm surge: Large rise in sea levels caused by low pressure and high winds pushing water toward the coast.

Question 42

Conditions favouring wildfires

Answer 42

Vegetation type: Thick, close together vegetation allows fires to spread quickly and easily. Trees and thick bushes. Vegetation with flammable oils like eucalyptus. Grasslands do not burn as intensely. Fuel characteristics: Vegetation should be dry to allow it to catch. Finer vegetation causes fires to spread quicker but larger, thicker forms of vegetation burns for longer and more intensely.

Question 43

Haiti 2010 Earthquake

Answer 43

- More than half the population lived in rural areas. - 3.5 million people were affected of a population of 9.7 million. - Over 200,000 estimated deaths and 300,000+ casualties - approx. 300,000 homes damaged or destroyed - 1.5 mil were homeless

Question 44

Mount Nyiragongo 2002 Volcano

Answer 44

- 80,000 people left homeless - 147 people killed - Goma split in half by lava spills - 40% of Goma destroyed

Question 45

Eyjfjallajokull

Answer 45

- No deaths - Roads surrounding the volcoano were shut down - Farmers and their families were evacuated from the area - Fresh fish imports were affected - a major industry - Flood, an eruption partially melted a glacier and set off a major flood - 700 evacuated