Natural Hazards Flashcards
1
Q
Natural hazard
A
A natural event that causes a risk to life
2
Q
Hazard risk
A
The probability of chance that a hazard will occur
3
Q
Hazard perception
A
How people perceive a hazard
4
Q
Fatalist
A
The approach that there is nothing that can be done to prepare for a hazard
5
Q
Geophysical hazard
A
Tectonic based hazards
6
Q
Atmospheric hazard
A
An air based hazard
7
Q
Hydrological hazard
A
Water based hazard
8
Q
Park model
A
Considers that standard to living/ quality of life and response to a natural hazard
9
Q
what is the hazard management cycle
A
Cycle showing the different stages of a hazard response
10
Q
Adaption to hazard
A
Adapting to the effects of a hazard - changing your way of living
11
Q
Mitigation to hazard
A
Reducing the impact a hazard has
12
Q
Frequency
A
How often a hazard occurs
13
Q
Magnitude
A
The strength of an earthquake
14
Q
Slab pull
A
Slabs at destruction boundary is pulled down into the mantle (by gravity and pressure)
15
Q
Ridge push
A
Plate boundary where slabs are pulled apart (constructive+divergent)
16
Q
Earthquake
A
The shaking of the earth’s crust due to plate movement
17
Q
Fold mountains
A
Where two continental plates meet and are pushed together causing the land to fold and push upwards
18
Q
Rift valleys
A
Land falls into the space that the plates left as they move apart at a constructive plate boundary
19
Q
Subduction
A
The more dense plate is forced beneath the other plate and subducted (then melted)
20
Q
Lava flows
A
Streams of molten rocks that pour from an erupting vent
21
Q
Lahars
A
A mixture of hot or cold water and rock fragments which flow down the steep side of a volcano
22
Q
Pyroclastic flows
A
High density fast flowing currents of hot gas and volcanic matter that flows along the ground away from the volcano at high speeds
23
Q
Ash fallout
A
Fine material derived from volcanic glass, rock and crystal particles
24
Q
Volcanic gases
A
Gases that are produced by volcanic eruption
25
VEI
The volcanic explosively index
- a measure of the intensity of a volcanic eruption
- scale of 1-8
26
Magma viscosity
The flow of magma
27
Landslides
Rock fall and movement of land - caused by earthquakes
28
Liquefaction
The mixing of sand or soil and groundwater
29
Seismic waves
Waves of energy that travel through Earth’s layer
30
Seismograph
The graph created from a seismometer that determine how much shaking occurred
31
Mercalli scale (MMI)
Measures the effect that an earthquake has on the earths surface
- 1-12
32
27 degrees
Temperature of water needed to form a tropical storm
33
Cyclone, hurricane, typhoon
Names of tropical storms depending on where they are formed in the world
34
Coriolis effect
Track of storms - tropical storms can’t move in a straight line as the earth moves
35
Eye wall
The most dangerous section of the storm
| - surrounds the eye
36
Eye
The centre of the storm where it is the calmes
37
Wildfire triangles
Triangle showing what is needed for a wildfire to start
- heat
- oxygen
- fuel
38
Smokey bear
American educational tool which is used to explain the risk of wildfires
39
Success
Whether the aim has been met (within hazard management)
40
Plate tectonic theory
- tectonic plates move due to the convection currents in the asthenosphere
> convection currents are caused when less dense magma rises, cools and sinks
41
Convection currents
The molten rock in the mantle aids the movement of plates
42
Tephra
Fragments of rock that are ejected from a volcano
43
Plinian eruptions
Highly explosive, large eruption column, range of tephra and pyroclastic flows
44
Richter Scale
A magnitude scale to measure the magnitude of an earthquake
45
Why is low pressure needed for a tropical storm
Low pressure causes air to rise - leads to the formation of thunderstorms which accumulate together to form a tropical storm
46
Saffir simpson scale
The scale that measures the strength of tropical storms based on wind speed
- scale of 1-5
47
Ladder fuels
Vegetation that allows for fire to travel and spread upwards from the forest floor
48
El nino
A band of warm ocean water that develops in central and east-central regions of the pacific
49
Pre-disaster phase of the park model
- mitigate
- prepare to minimise the risk
- adaption
50
Relief phase of the park model
The immediate response
- focused on rescue
- happens in hours and days
- help comes from charities
51
Rehabilitation phase of the park model
Efforts on restoring the physical community
- recovery
- improvement
- aspects of rebuilding
- happens in days and weeks
52
Reconstruction phase of the park model
Where permanent changes are introduced to restore the quality of life and economic stability
- getting back to normality but better than before
- includes mitigation and preparedness
53
Stages of the convection currents in the mantle
1. Heat source - radioactive decay in the earth’s core
2. Rising limb of the convection currents. Heated rock in the mantle rises as it is less dense
3. Semi molten rock spreads out carrying the plates above it
4. Plates move due to the movement of convection currents below
5. Cools and sinks back down to be reheated
54
Plate tectonics evidence
- Jigsaw fit - there is a similar outline of coastlines of east south America and west Africa
- geological fit - evidence of ancient rock outcrops in east south America and west Africa
- fossil evidence - examples of evidence found on separate continents
55
What type of plates are at destructive boundary
Continental and oceanic
56
What type of plates are at constructive boundary
Any plate type
57
What type of plates are at conservative boundary
Any plate type
58
What type of plates are at collision boundary
Continental and continental
59
Landforms at a constructive boundary
- mid ocean ridges
- rift valleys
- volcanoes
- earthquakes
60
Landforms at a destructive boundary
- Powerful earthquakes
- volcanoes
- fold mountains
- ocean trenches
- island arcs
61
Landforms at conservative boundaries
- powerful earthquakes
62
How are fold mountains formed
- formed at a collision boundary
- the two plates move together
- this causes the plates to buckle and rise up
- eg himalayas
63
Spatial distribution of tropical storms
North and south of the equator in the tropics of cancer and Capricorn
64
Frequency of tropical storms
More powerful and those reaching land are becoming more frequent
65
Regularity of tropical storms
Irregular as they do not follow the same route
| - they do occur at certain months of the year depending on where they are in the world
66
Predictability of tropical storms
Satellite tracking
67
Tropical storm
A low pressure, spinning storm with high winds and torrential rain
68
Conditions for a tropical storm
- 27C
- at least 50 m
- no less that 5 degrees on either side of the equator
- unstable air pressure
69
Primary effects of seismic hazards
- environmental = fault lines, liquefaction
- economic = buildings destroyed
- social = buildings collapse, trapped people
- political = government building destroyed
70
Secondary effects of seismic hazards
- environmental = radioactive materials, freshwater ecosystems flooded
- economic = economic decline, high cost of rebuilding
- social = gap pipe rupture, contaminated water, tsunami damage
- political = political unrest, borrowing money, initial chaos and lawlessness
71
Spatial distribution of natural hazards
Along all boundaries
72
Frequency of seismic hazards
Occur everyday
73
Regularity of seismic hazards
No pattern, are random
74
Predictability of seismic hazards
Impossible to predict
75
Prevention methods for volcanic hazards
- can’t be prevented
| - can only prevent risk to people
76
Preparedness for volcanic hazards
- monitoring
- education on volcanoes
- evacuation plans
- trained responders
77
Mitigation of volcanic hazards
- direct intervention
- strengthening buildings
- evacuation and exclusion zones
- emergency aid and rescue
78
Adaption to volcanic hazards
- moving away
- capitalise on opportunities
- change professions
79
Wildfires
A large uncontrolled fire that quickly spreads through vegetation
80
Conditions for wildfires
WILDFIRE TRIANGLE
- fuel (ladder fuels)
- oxygen
- heat
- extra: climate, weather
81
What affects the behaviour of wildfires?
- weather
- topography
- fuel type
82
Primary effects of tropical storms
- environmental = eroded beaches, habitats destroyed
- economic = agricultural land damage, businesses destroyed
- social = drowning, debris
- political = government buildings destroyed
83
Secondary effects of tropical storms
- environmental = salt water contamination, animals displaced, changing water course
- economic = high cost of rebuilding, loss of income
- social = homelessness, polluted water, food shortage
- political = debt from aid
84
prevention of tropical storms
> cannot be avoided
| > mitigate climate change - prevent high category storm
85
preparedness for tropical storms
> education
> evacuation plans
> satellite image tracking and warning system
86
mitigation of tropical storm
> search and rescue
> strengthen homes
> clearing loose debris before storm
87
adaption of tropical storms
> move away
| > design buildings to with stand damage and add flood defences
88
formation of a tropical storm
1) strong upwind movement over air over ocean of 27C
2) evaporated air cools as it rises and condenses to form towering thunderstorm clouds
3) condensing air releases energy which powers the storm and draws up more water
4) several small thunder storms combine to form a giant spinning storm (surface winds exceed 120km/h)
5) storm is carried across the warm ocean it continually gathers strength and energy
6) storm develops an eye where air rapidly descends - most intense are found in the eye wall
7) on landfall the storm's energy supply is cut off. friction with the land slows and weakens it, warm water will strengthen it
89
inner core
> solid ball of iron/ nickel
| > heat is responsible for earth's internal energy
90
outer core
> semi-molten
| > iron/ nickel
91
mantel
> asthenosphere - semi molten, convection current, bottom section
> lithosphere - broken into plates, is within mantle, top of crust
92
crust
> thin top of lithosphere
> oceanic crust (dense and destroyed)
> continental crust ( less dense and not destroyed)
93
primary envrionmental effects of wildfires
> air pollution
> water pollution
> toxic gases
> habitats destroyed
94
secondary environmental wildfire effects
> stimulates seed germination
> increase CO2
> animal migration
95
primary economic effects of wildfires
> businesses destroyed
> agricultural land damaged
> cost of fighting fires
96
secondary economic wildfire effects
> high rebuilding costs
| > lose of tourism and cancelled planes
97
prevention of wildfires
> cannot be overall avoided
> human - caused can be prevented
> controlled burning can prevent large fires
98
preparedness of wildfires
> public awareness
> evacuation plans and training
> satellite image tracking
> red flag warning systems
99
mitigation of wildfires
> search and rescue
> removing flammable material
> spraying water and fire retardant into area
100
adaption of wildfires
> move away
> fire breaks
> reducing carbon footprint
> insurance to cover damage
101
what are hotspots
areas of volcanic activity not related to plate boundaries
> hot magma plumes from mantle burning weaker parts of crust
> plume stays in same place but plates move
102
prevention seismic hazards
> can't be prevented
| > liquefaction can be prevented through soil stabilisation
103
preparedness for seismic hazards
> awareness strategies and education
> earthquake and tsunami warning systems
> evacuation plans and training
104
mitigation for seismic hazards
> search and rescue
> demolishing older, unsafe buildings
> tsunami wave breaks and sea walls
105
adaption to seismic hazards
> move away or changing lifestyle choices
> insurance
> specially designed buildings
106
formation of the east African rift valley
1) up warping of the crust takes place as magma rises as plates are driven apart
- tensional faults and cracks appear in the surface allowing for gasses to be emitted
2) plates continue to move apart as a rift valley is formed
3) huge blocks of crust descend into the mantle creating the valley
4) up welling magma creates volcanoes
107
graben
the valley/ plate that had dropped
108
horst
the land that has been pushed up
109
p waves
```
> pulse waves
> moves like a slinky
> forward and backward movement
> fastest
> moves though solid and liquid
```
110
s waves
> whole body moves up and down
> very damaging
> slower
> can't move through liquid
111
rayleigh waves
> up and down motion like a wave
> more damaging than p waves
> slower
> moves along the surface
112
love waves
```
> lateral motion
> snake like
> not much movement
> slowest
> surface waves
> some damage caused
```
113
shield volcanoes
> gentle slopes and a wide base
> frequent eruptions of basic lava
> lava flows at high speeds and for long distances before cooling]
> usually non-violent eruption
> non-viscous lava due to basaltic composition
> found at constructive boundaries
114
composite volcanoes
> steep sided with a distinctive cone shape
> high with a narrow base
> explosive eruptions of lava and ash
> layers of alternating ash and lava
> viscous lava builds in layers and does not flow far from the crater
> found at destructive boundaries
115
hazards caused by volanoes
```
> lava flows
> lahars (mudflows)
> floods
> tephra (ejected rock)
> toxic gases
> acid rain
> pyroclastic fall out (clouds of ash and gas)
> pyroclastic flow (gas, ash and rock flowing down the side)
```
116
hazard management cycle stages
> preparedness (being ready)
> response (immediate action)
> recovery (long term response)
> mitigation (lessen the effects of another hazard)
117
why is the hazard management cycle better than the park model
hazards and there response are cyclical - making hazard management cycle more useful
> the cycle will always continue as areas will always experience hazards multiple times
118
hazards caused by tropical storms
> high winds
> flooding
> landslides
> storm surges
119
primary environmental effects of volanic hazards
ecosystems damaged and wildlife killed
120
secondary environmental effetc sof volcanic hazards
> acid rain
| > adding top the greenhouse effect
121
primary economic effects of volcanic hazards
businesses are detroyed
122
secondary economic effects of volcanic hazards
jobs lost
123
primary social effects of volcanic hazards
> people killed
| > homes destroyed
124
secondary social effects of volcanic hazards
```
> fires
> mudflows
> floods
> trauma
> homlessness
```
125
primary political effects of volcanic hazards
> government buildings destroyed
126
secondary political effects of volcanic hazards
> conflicts over governmental response
127
hazards caused by seismic events
```
> shockwaves
> tsunami
> liquefaction
> landslides
> avalanches
```
128
natural causes of wildfires
> lightening strikes
> volcanoes
> spontaneous combustion
129
human causes of wildfire
```
either accidental or arson
> lit cigarettes
> BBQ's
> agriculture
> trainlines
> etc
```
