Natural hazards term 1! Flashcards

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1
Q

What types of natural hazards are there?

A
Wildfires 
Earthquakes land slides 
Drought 
Volcanoes 
Tsunami 
Tropical storm 
Floods
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2
Q

What is HICs perspective of natural hazards due to economy status?

A
  • take it more seriously
  • educated
  • adapt the area
  • put government funds towards natural hazard responses and mitigation
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3
Q

What is LICs perspective of natural hazards due to economy status?

A
  • may be used to it more so doesn’t effect them
  • can’t put systems into place as can’t afford to
  • there jobs may rely on the natural hazard
  • aren’t educated
  • risk to reward
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4
Q

What is a hazard?

A

Event that causes threat to human life

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5
Q

What is hazard perception

A

How people view the risk of a hazard

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6
Q

What is an Earthquake

A

When 2 plays boundaries slide past each other or make contact cause the ground to move

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7
Q

What is a volcano

A

When 2 plates push together and the ground rises, creating a mound with lava inside

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8
Q

What is hazard risk?

A

Hwo powerful or distributive the hazard is

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9
Q

What is geological hazard

A

An earth movement based hazard

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10
Q

What is a tropical storm

A

An atmosphere storm forming over oceans

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11
Q

Where are volcanoes and earthquakes mostly based at

A

Usually at coastal areas of countries but always at plate boundaries , usually in the south more than the north

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12
Q

What is park model

A

It is a hazard response that gives indications and directions on how a country should respond to a hazard. Its aim is to show the effects of a hazard on quality of life over a sequence of time.

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13
Q

What are 4 stages of park model

A

Stage1: pre disaster
Stage2:relief (hours/days after), immediate response
Stage3:rehabilitation stage (days/weeks) more complex than relief, building infrastructures to deal with hazard effects
Stage4:reconstruction
(Weeks/years) permanent changes to the area to change quality of life and economy

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14
Q

What is resilience

A

How able the community is to adapt and recover

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15
Q

What is emergency

A

The state at which a normal procedures are stopped and extra ordinary measures are taken

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16
Q

Positives of park model

A

Helps to visualise what to do after an event, gives time slot as to when these responses should be done

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17
Q

Negatives of park model

A

Doesn’t take in consideration economy, hazard magnitude, responses from indoor or outdoor relief, countries may not follow this

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18
Q

What is hazard response cycle

A

A cycle of events that should happen after a hazard for responses

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19
Q

Steps to hazard response cycle

A

Step1:preparation (actions prior to event to get necessary resources or systems put in place
Step2:hazard occurs
Step3:response,(rescue and evacuation, relief and external support)
Step4:recovery(long term recovery, internal and reconstruction)
Step5:prevention/mitigation (ongoing process to lessen the severity of hazard on people/property)

  • preparation
  • response
  • recovery
  • mitigation
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20
Q

Positives of hazard response cycle

A

Gives each step a country needs to take, talks about what to do before an event

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21
Q

Negatives of hazard response cycle

A

Doesn’t include times or suggest about a countries economy or finances that will be taken into account in responses effectiveness

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22
Q

Destructive plate margin (convergent)

A

Plates move together and the oceanic sinks under the continental volcanoes, earthquakes, fold mountains, ocean trench)

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23
Q

Constructive plate margin

Divergent

A

When two plates move away from each other

Volcanoes, mid ocean ridge, rift valleys

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24
Q

Conservative plate boundary

A

Two plate slide past each other

Earthquakes

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25
Q

Collision/convergent plate boundary

A

2 continental plates collide and the oceanic plate sinks under the continental plate (subduction)

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26
Q

Oceanic and continental crust

A

Oceanic is heavier and younger,

Continental is lighter and older

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27
Q

Layers of earth

A

Crust
Mantle
Outer core
Inner core

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28
Q

Lithosphere and asthenosphere

A

L:solid top layer of crust in which plates are formed
A:soft plastic like rock in upper mantle

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29
Q

What was wagener theory and how did he discover it

Pargea: land before it broke

A

-He believed that all plate boundaries and countries were once one. -Jigsaw(countries fitting together), -tectonic(same old fold mountains in Different countries over the world), -geological (S America and W Africa had same ancient rock canyons), fossils (same animals that shouldn’t have been able to survive in different climates)

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30
Q

Convection currents

A

Radioactive decay happens in earths core, rising limb of convection current causing molten rock to melt, semi molten rock spreads out at angle and carries the plate above, this then cools and sinks. Plates move on direction of molten movement

31
Q

What is paleomagnetism

A

New rock forms at an ocean ridge on either side of it. Rising magma causes the oldest rock to move further down the slope and youngest to be at the top

32
Q

Formation of African Rift Valley

A

Magma moved up causes ground to rise, fault cracks are created , plates move apart causing valleys to fall into the mantle
--_-

Somalian and Nubian plates caused this

33
Q

Shield volcanoes

A

Low and flat volcanoes , less dangerous as can’t build up masses of lava unlike composite volcanoes

34
Q

Oceanic and continental boundary

A

Oceanic is thinner and more dense so it sinks (subduction)

Volcanoes and fold mountains

35
Q

Oceanic and oceanic convergence

A

Oceanic (heavier and older) is forced under the other oceanic plate (lighter and younger)
Causes earthquakes and ocean trenches

36
Q

Continental and continental

A

Two plates collide with eachother, the heavier and denser one sinks (subduction) and causes the plate on top of teh sunken one to buckle, this creates mountains (earthquakes and young fold mountains)

37
Q

What is a hot spot on a volcano

A

Area on earth over a mantle plume

Mantle plume: area under the rock out layer of earth where magma is hotter than surrounding ones

38
Q

How are volcanoes formed

A

The mantle plume doesn’t move so when two crusts are pushed together or apart the lava rises with the moving earth

39
Q

VEI

A

volcanoes explosively index measures intensity of volcano eruptions
Lower down the VEI means they happen more often but smaller

40
Q

Geological observations of monitoring volcanoes

A

Slope angle: tilt meter is used to measure the change in slop, when a volcanoes is active/about to erupt it changes shape

41
Q

How does Seismic activity help monitoring volcanoes

A

Increase in seismic waves hint at eruption. Measured using seismograph

42
Q

Gas emissions to monitoring volcanoes

A

As magma rises to surface and it’s pressure decreases gases escape, they then drop prior to escape as magma hardens and seals on the gas.

43
Q

Formation of earthquake

A

Pressure buildings up at the point where 2 plates meet, sudden release (rock failure) the waves cause the ground to shake

44
Q

P waves

A

Move through solid and liquid, moves back and froward

45
Q

S waves

A

Move up and down only through solid but causes more damage

46
Q

Surface waves (L)

A

Sideways motion, most destructive outside the immediate area, first feeling of movement

47
Q

R waves

A

Along the surface, rolling motion causing earth to move up and down and is the most shaking felt

48
Q

Formation of tsunami

A

The ground beneath the water is moved up and down abruptly, mass of water is displaced and starts moving in different directions

49
Q

Richer scale

A

Measure the strength of earthquake (10x more powerful then number before)

50
Q

Mercalli scale

A

Measures the damage that is done on humans and infrastructure High numbers mean the earthquake is more dangerous to people

51
Q

What is tropical storm

A

Violent rotating storm which occurs at the mid latitudes, 27 degrees/ equator as hottest place on earth

52
Q

Formation of tropical storm

A

1: Strong winds upward bringing water up due to the warm air from 27degrees waters
2: the evaporated water cools as it rises and forms storm clouds
3: condensing air releases energy to power storm
4: storm is carried across warm water
5: storm develops and eye
6: several small storms combine to form a giant spinning storm.

53
Q

Saffir Sampson scale

A

Measures the damage done by tropical storms 1-5

54
Q

What is wildfires

A

Any rural fire which is uncontrolled and spreading .

They need heat source, fuel to burn, oxygen supply and topography (fire moves quicker going upwards)

55
Q

How to prevent wildfires

A

Water plants/keep area near home hydrated, don’t start fires near furled areas, reduce green house gas emissions

56
Q

What is slab pull

A

geophysical mechanism whereby the cooling and subsequent densifying of a subducting tectonic plate produces a downward force along the rest of the plate.

57
Q

What is ridge push

A

With rising magma, tectonic plates are push outwards (divergent), ridge push is when plates are forced down hill

58
Q

What are volcanic gases and what are it’s effects

A

•Volcanic gases are composed mainly of water, carbon dioxide, and sulfur dioxide. During violent eruptions, these gases are injected into the stratosphere. There, the sulfur dioxide reacts with water to form microscopic droplets, or aerosols, of sulfuric acid.
•Effects: The effects of volcanic gases on life may be direct, such as asphyxiation, respiratory diseases and skin burns; or indirect, e.g. regional famine caused by the cooling that results from the presence of sulphate aerosols injected into the stratosphere during explosive eruptions.

59
Q

What is acid rain and what are it’s effects

A

•how does it occur: the sulfur dioxide gas emitted from the volcano reacts with oxygen and moisture in the atmosphere to produce fog, volcanic smog, and acid rain which can be very corrosive
•dangers: the acid rain can travel for miles causing issues in surrounding areas and can cause health problems
•effects: This can pose serious risks to people and animals. Breathing air with more than 3% CO2 can quickly lead to headaches, dizziness, increased heart rate and difficulty breathing. At mixing ratios exceeding about 15%, carbon dioxide quickly causes unconsciousness and death.

60
Q

What is ash fallout and what are it’s effects

A

•Volcanic ash is formed during explosive volcanic eruptions. Explosive eruptions occur when gases dissolved in molten rock (magma) expand and escape violently into the air, and also when water is heated by magma and abruptly flashes into steam. The force of the escaping gas violently shatters solid rocks.
•ash from a volcanic eruption

61
Q

What is pyroclastic flow and what are it’s effects

A

•A pyroclastic flow is a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases. Pyroclastic flows can also form when a lava dome or lava flow becomes too steep and collapses.
•Reaching speeds greater than 100 kilometres per hour (60 miles per hour) and temperatures between 200° and 700° Celsius.
•pyroclastic flows are considered the most deadly of all volcano hazards.
•On the margins of pyroclastic flows, death and serious injury to people and animals may result from burns and inhalation of hot ash and gases.

62
Q

What is mudflow

A

• is a flow of water that contains large amounts of suspended particles and silt. this causes irreversible sediment entrainment.
• Landslides are caused by disturbances in the natural stability of a slope. They can accompany heavy rains or follow droughts, earthquakes, or volcanic eruptions. Mudslides develop when water rapidly accumulates in the ground and results in a surge of water-saturated rock, earth, and debris.

63
Q

What is tephra and what are it’s effects

A

• The term tephra defines all pieces of all fragments of rock ejected into the air by an erupting volcano. Most tephra falls back onto the slopes of the volcano, enlarging it.
• When a volcano explodes, it releases a variety of tephra including ash, cinders, and blocks.

64
Q

What is nuée ardente and what are it’s effects

A

• A nuée ardente is a turbulent, fast moving cloud of hot gas and ash erupted from a volcano.
• They can engulf victims within seconds. Escape on foot or by vehicle is nearly impossible. People outside the destroyed area can suffer burn injuries or asphyxia from inhaling hot toxic gasses and ash. This slows down how quick emergency services can get there as the hot gas will harm anyone near it and planes/transport will be affected by it

65
Q

What are lava flows and what are its effects

A

• Lava flows are streams of molten rock that pour or ooze from an erupting vent. Lava is erupted during either nonexplosive activity or explosive lava fountains.
•lava flows, however, can bury homes and agricultural land under tens of meters of hardened black rock; landmarks and property lines become obscured by a vast, new hummocky landscape. can cause severe burns and often burn down vegetation and structures.

66
Q

What’s a lahar

A

•a lahar is a mixture of hot or cold water and rock fragments which flows down the steep side of a volcano.
•This does not have to be during or immediately after an eruption but may be some time afterwards.
•When they stop flowing lahars are capable of settling like concrete and being very hard to therefore remove following an event.
•This can slow down a recovery effort and in some cases means an area may remain abandoned.

67
Q

What is magma viscosity

A

•viscosity is the resistance to flow
•The effect of temperature on viscosity is intuitive. the higher the temperature, the more fluid a substance becomes, thus lowering its viscosity.

68
Q

What is coriolis effect

A

Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere.

69
Q

What is ladder fuels (wild fires)

A

•firefighting term for live or dead vegetation that allows a fire to climb up from the landscape or forest floor into the tree canopy.
•movement of fire across vegetation

70
Q

What is El Niño

A

refers to a warming of the ocean surface, or above-average sea surface temperatures, in the central and eastern tropical Pacific Ocean.

71
Q

What is plinian eruptions

A

extremely explosive eruptions, producing ash columns that extend many tens of miles into the stratosphere and that spread out into an umbrella shape.

72
Q

What are the characteristics of a tropical storm

A

-27 degrees water
-50-60m depth of water
-8-20 degrees north or south of the equator
-75mph wind
-low wind-sheer

73
Q

What is mitigation

A

the action of reducing the severity, seriousness, or painfulness of something.

74
Q

What is adaption

A

Things done to reduce the chance of an event happening (dealing with the cause)