Hazards Flashcards
(112 cards)
1
Q
What is a Geophysical hazard?
A
a Hazard triggered by internal processes, such as Tectonic movement.
2
Q
What is a Hydro- Metrological hazard?
A
A hazard triggered by water, and anything associated with weather patterns.
3
Q
What does the Degg’s model say?
A
A vulnerable population and a hazardous event, creates a disaster.
4
Q
Why is hazard risk changing?
A
frequency is increasing due to climate change
countries are less able to cope, due to poverty and urbanisation.
5
Q
what is the Hazard management cycle?
A
Pre-disaster
Responses
Post disaster
mitigation
6
Q
What is fatalism?
A
The concept that forms in areas at high risk, where if an event is going to occur then it can’t be changed.
7
Q
How does a volcano form?
A
The denser oceanic crust is subducted under the continental crust, creating a deep ocean crust.
magma rises through the lithosphere and creates a volcano.
The oceanic plate continues descend in a convectional cell.
8
Q
What are the four types of plate margins?
A
Destructive- Denser plate is subducted.
Constructive- Plates mover past each other
Conservative- Plates move apart.
Collision- Plates collide
9
Q
What are the two types of plate movement?
A
Ridge Push
Slab Pull
10
Q
What determines the destructivity of a volcano?
A
The viscosity of its magma.
Low- runny magma and shallow sided volcano
high- sticky thick magma and steep sided volcano
11
Q
What affects viscosity?
A
Temperature- thinner
Silica content- thicker
Dissolved gasses- thinner
12
Q
What are the primary impacts of a Volcano?
A
Ash
Lava
Pyroclastic flows
Gas Lava bombs
13
Q
What are secondary impacts of a Volcano?
A
Acid rain
climate change
Tsunami
Lahar (mudflow)
Flooding
14
Q
What is a pyroclastic flow?
A
Move at very rapid speeds, can be a caused by dome collapsing or a collapse of volcanic column.
Can also be known as ‘Nuee Ardente’
15
Q
How are earthquakes measured?
A
Mercalli scale- how much damage has been caused
Moment of magnitude- Based on the total moment (the distance a fault moved)
Richter scale- measure energy of an earthquake
16
Q
What is the benioff zone?
A
found along a subduction zone, results from the oceanic crust forced under the continental crust.
17
Q
What are the two types of seismic waves?
A
S- waves (Secondary waves)
P- waves (Primary waves)
18
Q
How doe P&S waves move?
A
Surface waves- long waves that take longer to complete a cycle of motion.
Rayleigh waves- Have a rolling motion, produce both horizontal and vertical movements
Love waves- fast and shake the ground at right angles
19
Q
What are primary impacts of earthquakes?
A
Ground displacement
Falling buildings
20
Q
What are secondary impacts of earthquakes?
A
Liquefaction
Landslides
Tsunamis
Fires
21
Q
What is Liquefaction?
A
The shaken loose sediment draws up water, this liquifies the surface. This then begins to solidify quickly, and becomes like quicksand.
22
Q
What are short term responses to earthquakes?
A
Emergency aid
Search and rescue
medical care
shelters
being prepared for after shocks
23
Q
What are long term responses to earthquakes?
A
Rebuilding infrastructure
mitigating against further quakes
educating the people
24
Q
What are short term responses to volcanoes?
A
Emergency rescue
evacuation
Providing Aid
25
What are long term responses to Volcanoes?
Restoring Power and water
Rebuilding Infrastructure
Mitigating against future Volcanic events
26
What defines a hazard?
A threat of substantial loss or impact to life. Similarly, damage done to property through a natural event.
27
What is the Park model?
It demonstrates the relationship between hazards and the human response to them.
28
In the Parks model, what are the three phases of response?
Relief
Rehabilitation
Reconstruction
29
What are the phases of the hazard management Cycle?
Preparedness
Response to the Hazard event
Recovery post damage
Mitigate against any more hazard events.
30
What is Plate Tectonic Theory?
That the continental drift is caused by the movement of tectonic plates, through discovering that the newest rocks were found in the centre of the Atlantic Ocean.
31
What is Ridge Push?
The weight of gravity pushes the older part of the plate to the front, acting as a push.
32
How does a Mid-Ocean ridge form?
Divergence within the ocean, forms chains of submerged mountain ridges that stretch kilometres. Within the Mid- Ocean Ridges deep rift valleys occur, which continue to widen due to rising magma.
33
What is Slab-pull?
After subduction, the lithosphere sinks into the mantle, with its weight helping to "pull" causing it to melt.
34
What is a Rift Valley?
Valleys that are formed when the lithosphere stretches, causing it to fracture into sets of parallel faults and collapsing the land in-between them.
35
Where can an example of a Rift Valley be found?
East Africa's Great rift valley. It extends 5,950km.
36
What occurs when at a destructive plate margin?
It subducts under the more dense continental plate. The point of the collision is marked by a Deep Ocean Trench.
37
Where can a example of an Ocean Trench be found?
Marianas Trench- Pacific Ocean
38
What is the name of the area where the crust melts?
Benioff Zone
39
What is by product of a destructive plate margin?
Fold mountains, as the continental plate scrunches up.
40
What is the name for a volcano found at a destructive plate boundary?
Andesitic Volcano.
41
What is the Asthenosphere?
The zone of the mantle that lies between the mantle and the lithosphere, usually hotter than th mantle.
42
What are a by product of two continental plates meeting?
Fold mountains.
43
What occurs at conservative plate boundaries?
Powerful earthquakes.
44
Where can a Conservative plate boundary be found?
San Andrea’s fault- California.
45
What are the types of magma?
Basaltic
Andesitic
Rhyolitic
46
How can volcanos be measured?
The Volcanic Explosively Index.
47
How can Volcanoes be monitored?
Using seismometers and seismographs.
48
What measures the upward movement of magma?
Magnetometers, demonstrating the change within the volcano itself.
49
What are the causes of mudflows/ Lahars?
Flows of ash, cinde, soil and Rock.
Eruptions that eject water directly from a lake.
The rapid melting of ice or snow on the volcanos surface.
Heavy rainfall induced by the volcanic event.
Pyroclastic flows.
50
What are the relationships between constructive boundaries and the hazards occurring?
Basic volcanoes.
Shallow focus earthquakes.
New basaltic rocks form.
51
What is the relationship between hazard events and Destructive boundaries?
Explosive acid volcanoes.
Shallow and Deep focussed earthquakes.
Shallow focus quakes at collision zones.
52
What is the relationship between hazard events and conservative plate boundaries?
Shallow focus earthquakes.
53
How much of the worlds volcanoes are located on plate boundaries?
95%
54
How do Hotspots occur?
Decay within the earth's core generates extreme heat, if concentrated hot spots form around the core and heat the lower mantle.
55
How do magma Plumes occur?
They rise vertically in a hotspot, burning through the lithosphere to create volcanic activity on the surface.
56
What occurs to Magma Plumes after the movement of plates tectonics?
They create extinct volcanoes as the plate moves away from the hotspot.
57
Where is an example of Magma Plumes?
Hawaii.
58
What is the difference between oceanic and continental plates in relation to plate tectonic theory?
Continental plates are permanent, therefore will not sink into the asthenosphere due to their low density.
Oceanic plates are continually being formed at mid-ocean ridges, meaning they have younger age.
59
What are the types of volcanoes?
Classic cone shape.
Shield
Acid dome
Caldera.
60
What is the impact of a violent eruption?
It empties the magma chamber, and blows off the summit of the volcano.
61
What is Tephra?
Volcanic bombs and ash that are ejected out of the volcano, into the atmosphere.
62
What is a pyroclastic flow?
Gas and tephra, at extreme heat, that flow down the side of the volcano following an eruption.
63
What is a lava flow?
Streams of often rock, that pour through vents in the volcano. The speed they move at depends upon the type of lava.
64
What are pyroclastic flows often referred to as?
Nuees ardente.
65
How does flooding occur following an eruption?
Due to the heat, they can melt glaciers and ice caps. Similarly, the snow settle on volcanoes melts.
66
How does acid rain occur?
Volcanoes emit sulphur, which combines with the moisture in the atmosphere to create acid rain.
67
What are the primary hazards of Volcanic eruptions?
Pyroclastic flow
Tephra
Lava flows
Ash fallout
Volcanic gases
68
What are the secondary hazards of Volcanic eruptions?
Mudflows
Landslides
Acid Rain
Flooding
69
Which seismic was cause the most damage?
Love waves
70
What human activities can create earthquakes?
Mining
Fracking
Reservoir construction
71
How do earthquakes occur?
Friction along plate margins create stresses in the lithosphere. Finally, the rock is compromised and creates a fault, creating shockwaves.
72
What usually generates Tsunami's?
Earthquakes
Landslides
submerged volcanoes
Meteor strike
73
How do Tsunamis vary from normal waves?
Wavelength is much longer
Travel at faster speeds.
Low wave height.
74
How many Tsunamis are related to 'The Ring of Fire'?
90%
75
Where is the 'Ring of Fire' located?
Between the North American plate and Eurasian plate.
76
What type of boundary do most earthquakes happen?
Destructive
77
What type of quake occurs at constructive boundaries?
Close to the surface and narrowly concentrated.
78
What type of quake occurs at destructive boundaries?
Deeper focus, but shallower waves creating the quake.
79
What type of quake occurs at conservative boundaries?
Narrow zone of shallow depth quakes.
80
What is the new way of measuring earthquakes?
Moment magnitude Scale.
Calculates the total amount of energy released by a quake.
81
How can earthquakes be measured/ predicted?
They are difficult to predict, however knowledge of tectonic theory allows seismologists to be aware of the places most at risk.
82
How can Earthquakes be mitigated against?
Public education, through drills and checklists.
Rubber shock absorbers underneath buildings.
Risk assessments on newly developing areas.
Warning systems, such as Japan
83
What are the primary impacts of earthquakes?
Ground shaking
Buildings collapsing
Water and gas lines broken
Road and infrastructure damage.
84
What are secondary impacts of seismic events?
Provision of Aid
Spread of diseases through water
Civil disorder
Power cuts
85
What are the long term impacts of Earthquakes?
Higher unemployment
Repair and reconstruction
Long term illness- possible lower life expectancy.
Permanent changes to water drainage
Public discontent.
86
Why are tropical storms important?
They move warm temperatures from the tropics towards the poles, helping to regulate climates.
87
What are the characteristics of Tropical storms?
120kph wind speed.
Eye and eye wall are found in the centre.
Dry air from the stratosphere sinks as it warms.
88
What are the distributions of Tropical storms?
Formed around the tropics specifically across warmer oceans.
89
What affects the distribution of Tropical storms?
Storms derive their moisture from oceans, they slow down once reaching land.
Sea temperatures of at least 26 degrees are needed for a storm to form.
In areas of atmospheric instability, where warm air rises, it is likely for a storm.
Winds that move from different directions, prevent a tropical storm from forming.
90
What is the Coriolis effect?
The influence of the earths rotation, which helps to initiate the spin of a Tropical storm, and it increases with the distance away from the equator.
91
How does a tropical storm form?
Warm ocean.
Central vortex is created.
Winds begin to spiral outwards, when reaching 15km.
Clouds then form as the water cools and condenses.
92
What are the secondary impacts associated with Tropical storms?
Strong winds
Flooding
Storm Surges
Landslides
93
What is a storm surge?
Caused by low atmospheric pressure, along with the strong winds that drive it inland.
94
How are Tropical storms measured?
The Saffir Simpson scale. Which categorises them into 5 classifications.
95
What is the trend in frequency of hurricanes?
Currently there is none, however it is expected that within the next 10 years climate change will result in more storm events.
96
How can Tropical storms be predicted?
They mostly occur during late summer and early autumn.
The NOAA publishes a study, using sea temperatures, atmospheric conditions and short term climate cycles to demonstrate the predictions for the following year.
96
How can Tropical storms be predicted?
They mostly occur during late summer and early autumn.
The NOAA publishes a study, using sea temperatures, atmospheric conditions and short term climate cycles to demonstrate the predictions for the following year.
97
What are the primary impacts of Tropical storms?
Strong winds
Storm surge
heavy rainfall.
98
How can hurricane impacts be minimised?
Preparedness- Increases people's awareness of a hazard, through posters and campaigns.
Mitigation- engineering schemes, building up beaches and planting trees.
Coral reefs also provide a source of natural protection.
Disaster Aid- humanitarian relief and long term constructional aid.
Insurance- Have to follow certain building codes. It does however force out the poorest, who cant afford hurricane insurance.
Prevention- cloud seeding, whereby crystals are dropped into clouds to attempt to make it rain.
99
How do people tend to adapt to Hurricanes?
Land use zoning- allows low valued land to occupy coastal strips.
Raised foundations- houses are built higher, and have no residential floors on the bottom incase of flooding.
Wind resistant structures.
100
What conditions aid wildfires?
dry vegetation
ignition source- hot temps, or human vandalism
Climate characteristics- winds, hill slope and topography.
101
What type of tree aids wildfires?
Eucalyptus
102
What is an el-nino event?
occurs every 6-8 years
Warms the Pacific ocean off of South America.
Affects global climate patterns.
Means some places are heavily flooded, whilst others are very dry.
103
What is a La Nina event?
A cold event, with the opposite effect to an el-nino event.
Trade winds are much stronger, pushing warm water towards Asia.
104
Which winds are important in creating wildfires in California?
Santa Ana
105
What are the causes of wildfires?
Heat transfer from the sun, which 'preheats' the vegetation.
Firebrands- burning fragments of vegetation carried into dry areas by wind.
Gravity- causes firebrands to move downhill, igniting large amounts of vegetation.
106
What are the primary impacts of wildfires?
Destruction of habitats.
Short term serge of CO2 into the atmosphere.
People are displaced
Damage to infrastructure and homes.
Loss of crops and farm land.
107
What are the Secondary impacts of wildfires?
Depleted nutrient stores, due to a lack of vegetation.
Behavioural adaptation- people may have to abide by new rules and building regulations.
Update/ create preparedness and mitigation strategies.
Review laws involving leisure in countryside areas.
108
What impact can wildfires have upon global systems?
Loss of vegetation may result in less transpiration, and increase in surface runoff.
Nutrient cycles are damaged, as biomass in burnt.
Carbon stored within trees is released into the atmosphere.
109
How can wildfires be prevented?
Public awareness- Campaigns such as Smokey Bear, encourage safe woodland practises.
Controlled burning- Selectively burning areas, to prevent a fire breaking out rapidly.
110
How do people adapt to wildfires?
Learn to live with wildfires.
Planning regulations, to prevent people living in wildfire prone areas.
Building with environmentally friendly materials, meaning that if structures burn they don't harm the environment.
111
How can people prepare for wildfires?
Warnings are released via social media and the weather stations.
Establish fire breaks around homes. eg stacking wood away from the home, mow grass, cut back vegetation and dispose of debris around.
