natural hazards Flashcards
(155 cards)
1
Q
what are natural hazards
A
an event beyond human control that could threaten life and property
e.g. mount popocatepetyl
2
Q
what is a natural disaster
A
a hazard that has already happened causing death and destruction
e.g. japanese tsunami
3
Q
what is a natural event
A
an event that occurs such as a volcanic eruption or storm that do not pose a threat to humans
e.g. japanese island
4
Q
what factors affect the impact of hazards
A
- size of event
- preparedness
- duration
- population (density)
- relative wealth
- links
5
Q
what is the risk equation
A
hazard risk =
(vulnerability x hazard (type, frequency and magnitude) ÷ capacity to cope
6
Q
what are the large pieces the earths crust is broken down into called
A
tectonic plates - move a few cm each year
7
Q
what is the theory ab moving tectonic plates called
A
continental drift
8
Q
who discovered continental drift
A
Alfred wegener
9
Q
what are the 3 reasons Alfred Wegener thought the plates were moving
A
1) shells and salts up mountains
2) fossil mates across continents
3) uncanny “fit” between continents
10
Q
what are the diff layers of the earth
A
- crust: relatively thin and rocky
- mantle: properties of a solid but can flow very slowly
- outer core: made from liquid nickel and iron
- inner core: made from solid nickel and iron
11
Q
what if the diff. between continental and oceanic crust
A
- oceanic crust: younger, denser, thin (up to 10km), mainly has ocean on it
- continental crust: older, less dense, thick (up to 70km), mainly has landmass on it
12
Q
what is the lithosphere
A
crust and upper part of the mantle
13
Q
what is the area where the mantle and crust meet called
A
moho discontinuity
14
Q
what are convection currents
A
- movement (caused by heat) in the mantle cause the plates to move v. slowly each year
15
Q
how do convection currents cause plates to move
A
1) radioactive decay in the core heats the mantle
2) particles in the mantle close to the core become less dense as they are heated
3) particles rise nearer to the crust
4) as they move away from the core they cool and sink back down again
5) this creates a convection current
16
Q
what is ridge push
A
magma pushes up the plate boundary causing the plates to be pushed apart
17
Q
how does ridge push cause plates to move
A
1) the rising hot magma heats the surrounding rocks, causing them to expand and rise above surrounding land
2) where the plates move apart, the plates are pushed up. this means that gravity and the wight of the plate makes them move
18
Q
what is slab pull
A
pull of gravity on a plate that is being subducted
19
Q
how does slab pull cause plates to move
A
1) the oceanic plate is denser and heavier so is subjected beneath (forced under) the continental plate
2) as the plate sinks, it pulls the rest of he plate along with it
20
Q
what are the 4 types of plate boundary + examples
A
- constructive = mid-Atlantic ridge
- destructive = japan
- collision = himalayas
- conservative/ transform = California
21
Q
How do constructive plate margins work
A
- Convection currents in the mantle cause hot magma to rise, heating the rocks above them
- The tectonic plates move apart from each other bc of ridge push, the molten magma rises in between cools and forms new rock. This forms part of the new oceanic plate. The new plate sometimes fractures ad it is moved causing shallow usually small non-violent earthquakes.
- Most of the magma doesnt reach surface but pushes crust up to form ridges, magma that does rise spreads and solidifies forming shield volcanoes
22
Q
How do destructive plate margins work
A
- Pressure of oceanic and continental moving towards each other - sudden jolts cause major earthquakes
- Denser oceanic plate is subducted and sinks under the continental plate - forms ocean trench
- As oceanic plate sinks deeper into mantle it causes part of plate to melt. Hot magma forms in a magma chamber under pressure. Eventually rises up and can erupt forming violent volcanoes. Magma is viscous so solidifies to form steep sided composite volcanoes.
23
Q
How do collision plate margins work
A
- Two plates collide and bc they are made of same rock type neither gets subducted under, and as result compression forces plates to collide and form fold mountains. Earthquakes can occur here.
24
Q
How do conservative plate margins work
A
- Pressure builds up at margin as plates are being pulled along as they are pushed by convection currents. Eventually pressure becomes too great, rock fractures in an earthquake and jolts into a new position
- Land is neither created or destroyed so no volcanoes.
25
Where else do volcanoes form
Hotspots where the crust is thin and magma is able to break the surface
26
Where are most earthquakes and volcanoes found
Ring of fire
- 70% of all earthquakes
- 90% of all volcanoes
27
when and where was the New Zealand earthquake
kaikoura, north island, 14 nov 2016
28
what caused the nz earthquake
7.8 magnitude earthquake, caused by destructive and constructive plate boundary between pacific and indo-australian plate
29
what were the primary effects of the new Zealand earthquake
1. 2 people died
2. 50 people injured
3. tens of thousands of homes damaged and some destroyed
4. $8.5bn in damages
5. communication, water, sewage and power cut off
30
what were the secondary effects of nz earthquake
1. triggered up to 100,000 landslides
2. major one blocked Clarence river and caused major flooding, leading to evacuation of 10 farms
3. led to a tsunami of wave height 5m and left debris up to 250m in land
31
what were the immediate responses to the nz earthquake
- tsunami warning issued quickly
- coastal residents advised to fmove to higher ground
- 200 of most vulnerable people evacuated from kaikoura by helicopter within 24hrs of the earthquake
- International warships sent to kaikoura carrying supplies such as food, medicine and portable toilets
- power restored to most areas within a few hours
32
what were the long term responses to the nz earthquake
- $5.3 million given by kaikoura council to help rebuild water systems and harbours
- most road and rail routes repaired and reopened within 2 years
- new permanent water main built that withstands earthquakes by moving with them
33
when and where was the nepal earthquake
25th April 2015, epicentre in gorkha nepal
34
what caused the Nepal earthquake
- 7.8 magnitude earthquake caused by indo-australian plate being subjected by eurasian plate
35
what were the primary effects of the nepal earthquake
- 9000 ppl died
- more than 22k injured
- estimated 800k buildings destroyed
- 4mil left homeless
- $5bn in damages
- water tanks + pipes destroyed leaving 2 mil w/o clean water and sanitation
36
what were the secondary effects of the nepal earthquake
- triggered avalanches on Mount Everest which killed 18 people
- lack of clean water lead to outbreaks of typhus which killed at least 13 people
- mountain roads blocked preventing emergency aid reaching remote areas
37
what were the immediate responses to the nepal earthquake
- india and china sent teams to help residents rescue people trapped by debris (lack of tools and machinery slowed down efforts)
- charities such as Oxfam provided medicine, food and temp. water supplies
- Red Cross set up emergency shelters for 130k fams who had lost their homes
38
Why were the effects of the Nepal earthquake so severe
- densely populated
- high magnitude
- buildings badly built
39
How does geothermal energy work
Steam is heated by hot magma, steam turns a turbine which generates electricity
40
Why is geothermal energy a clean source of energy
It doesn’t release GHGs and it won’t run out
41
How much of Iceland’s energy comes from geothermal energy
30%
42
Why are volcanic soils fertile and therefore good for farming
Lava breaks over 1000s of years releasing minerals which fertilise soil
43
What percentage of earth’s surface are volcanic soils found on
Less than 1%
44
How much of the world’s pop. Do volcanic soils support
10%
45
Name a mineral that can be mined near volcanoes
Sulphur
46
Where is sulphur mined and can it be used to make
East Java indonesia, can be used to make matches, medicine, fertiliser
47
Why is mining dangerous
Little protective clothing, health problems + accidents are common
48
How many tourists visit volcanic sites each year
100 million
49
Why do ppl stay in tectonically active areas
They do not perceive the risk to be great or have emotional ties to an area
50
Why might ppl live in tectonically active areas
- v. fertile soil from minerals within the earth so crops grow easily
- tourism opp. so lots of jobs are generated
- generating electricity through geothermal energy so it is sustainable and v. cheap
- minerals (e.g. sulfur comes to the surface so that they can be sold
- family
51
What’s bad ab living in tectonically active areas
- they are dangerous if they are not monitored
- housing can be destroyed by eruptions
- ash can pollute rivers killing the fish
52
What are the 4 ways we can respond to earthquakes
- monitor
- predict
- plan
- protect
53
Define monitoring
Monitoring: recording physical changes such as earthquake tremors around a volcano, to help forecast when and where a natural disaster might strike
54
Define prediciton
Attempts to forecast when and where a natural disaster will strike, can be done for volcanoes but much less so for earthquakes
55
Define planning
Actions taken to enable communities to respond to, and recover from, natural disasters, through emergency evacuation plans, information management, comes and warning systems
56
Define protection
Action taken to eliminate long term risk to human life
57
What are 6 things that affect climate
1. Warm air rises, cold air sinks
2. Sinking air creates high pressure
3. Rising air creates low pressure
4. As you travel 100m upwards it gets colder by 1˚C
5. Surface winds blow for high to low pressure areas
6. Rising air - cools - -condenses - forms clouds and it rains
58
What does a beam of sunlight do at the equator
Solar energy strikes almost at a right angle and the energy is concentrated
59
What does a beam of sunlight do above and blow the equator
Sunlight hits surface at an angle so the energy is spread out
60
What conditions are needed for a tropical storm to form
- low pressure
- warm water - 27ºC or more
- coriolis effect
61
Where are tropical storms called in the pacific, Atlantic and Indian oceans
Pacific - typhoon
Indian - cyclone
Atlantic - hurricane
62
Where are tropical storms found
5º-30º north and south of the equator
- part. in north atlantic, pacific, indian
63
What is a tropical storm
Intense low pressure system formed over tropical waters
64
when are tropical storms most common
late summer months
northern hem: aug-oct
southern hem: nov-apr
65
what weather conditions do tropical storms bring
wind, rain, flooding, storm surge
66
how fast do winds have to be for the storm to be classed as a hurricane
74mph
67
what scale measures wind speed/potential damage for hurricanes
saffir-simpson scale
68
why is the saffir-simpson scale not always helpful in measuring potential damage?
storm surge can be more damaging
69
what happened when hurricanes hit land
lose energy and die out b/c they are fuelled by warm water
70
how can we predict storms
- previous data
- satellites
- monitoring sea surface temp.
71
explain the formation of tropical storms
- hurricanes draw energy for warm seas over 27ºC
- b/c water surface is v. warm, it evaporates, rises and condenses into storm clouds
- rising air creates low pressure which pulls surface winds in from edges of storm
- when vertical wind shear is low, clouds prevented from breaking up
- storms spin b/c of Coriolis effect
- as storm moves over ocean, energy from warm water strengthens storms so wind speeds increase
72
what is the Coriolis effect
winds blow from areas of high pressure to areas of low pressure. as earth rotates it causes winds to bend. this is known as the coriolis effect.
73
why don't hurricanes occur on the equator
there is no Coriolis effect at the equator
74
why directions do hurricanes spin in the northern hemisphere
bend to right, spin anti-clockwise
75
why directions do hurricanes spin in the southern hemisphere
bend to left, spin clockwise
76
what are high altitude winds called
jet streams
77
When and where was typhoon haiyan
Philippines on 8th nov 2013
- category 5 hurricane
78
How fast were wind speeds in typhoon haiyan
314 km/h
79
What percentage of tacloban was destroyed in typhoon haiyan
90%
80
What were the primary effects of typhoon haiyan
- 50% of houses destroyed
- 4.1 mil homeless
- 6k died
- $12bn in damages
- 75% of farmers and fishermen lost their income
- flooding caused by 400ml of rainfall
- 1.1 mil tonnes of crops destroyed
81
What were the secondary effects of typhoon haiyan
- infection and diseases spread due to contaminated water
- power supplies cut off for a month in some areas
- airport badly damaged
- by 2014, rice prices had risen by nearly 12%
- mangroves contaminated
- flooding caused landslides
82
what were the long-term responses to typhoon haiyan
- $1.5bn dollars in foreign aid
- oxfam replaced fishing boats
- in July 2014 gov declared long term recovery plan “Bring Back Better” buildings would be replaced and rebuilt to withstand future disasters
- mangroves replanted
- new storm surge warning system installed
83
what were the immediate responses to typhoon haiyan
- gov issued warnings for ppl to evacuate
- ppl evacuated to tacloban football stadium which later flooded
- emergency aid supplies arrived 3 days later by plane
- within two weeks, over 1mil food backs and 250kL of water distributed
- gov imposed curfew to reduce looting
84
how can the effects of tropical storms be reduced
- monitoring
- prediction
- planning
- protections
85
How does predicting and monitoring for tropical storms work
Data is fed into supercomputers which can then map the path of the hurricane and can give a 3 days warning. ab 70% accurate
86
How does predicting and monitoring reduce impacts
1. Allows ppl to be evacuated which saves lives
2. Allows govt and aid agencies too be ready to give immediate aid
87
What are problems predicting and monitoring tropical stroms
1. Can be wrong by up to 480 km so ppl may be evacuated for no reason - costly and time consuming
2. Doesn’t protect buildings
3. if you don’t have any means of comms then you can’t tell people
88
examples of predicting and monitoring tropical storms
- typhoon haiyan > 800k evacuated
* over 1 mil homes still damaged
- if done w/o planning can still lead to deaths - TH flooded evacuation centres
- fewer death - fishermen warned not to go to sea
89
describe the method of planning for tropical storms
aim to encourage people to plan what they need to have and do in the event of a tropical storm
-preparing disaster supply kits
- having fuel in vehicles
90
how does planning reduce impacts
people will be prepared and therefore have a plan
91
any problems w/ planning for tropical storms
1. doesn’t reduce the event
2. can be v. expensive to plan ahead
92
examples of planning for tropical storms
- evacuation of areas bound to be hit - typhoon haiyan
- storm shelters, military deployed planes + helicopters
93
describe the method of protection against tropical storms
building can be reinforced to reduce damage caused by forceful winds of tropical storms
- install hurricane straps between roof and walls
94
explain how protection reduces impacts
protects building and infrastructure from the storm
95
any problems w/ protection
1. can be v. expensive
2. can take a while to put in place
96
examples of protection against tropical storms
- building 30k houses w/ higher design standards
97
how much have sea surface temp.s increased by since 1880
0.9˚C
98
in which ways will climate change affect tropical storms
1. frequency
2. distribution
3. intensity
99
how will frequency of tropical storms be affected by climate change
ocean will stay at 27˚C for longer so *may* mean there are more storms as there is a longer time where they can form
100
evidence of frequency of tropical storms changing
in atlantic number of tropical storms has increased each decade
101
how will distribution of tropical storms be affected by climate change
as temps. rise more areas might be 27˚C or more so may occur in more areas - so far this hasn’t been recorded
102
how will intensity of tropical storms be affected by climate change
higher sea-surface temp. means more evaporation > more cloud formation > more energy > storms could be more powerful
103
evidence for intensity if tropical storms changing
intensity expected to increase by 2.11% by 2100
104
types of extreme weather hazards in uk
storms, floods, droughts, extreme cold weather => hydrometeorological hazards
105
facts for social effects of extreme weather
- 3 people died due to storm desmond
- in dec 2nd 2010 7k schools closed due to snow
- in nov-dec 2010 snow covered almost all of uk and was over 50 cm in hilly locations
- during storm desmond about 5200 homes flooded in cumbria and lancashire
106
facts for economic effects of extreme weather
- the ‘beast from the east’ cost the uk economy at least £1bn a day
- during drought in 2006, there was hose-pipe bans and campaigns to make people save water
107
what are social impacts of extreme weather
- homelessness
- injury
- death
- unable to move around area easily
-damage to homes and possessions
108
what are economic impacts of extreme weather
- high costs to fix damage to property
- disruption to transport
- shut down businesses
- loss of jobs temporarily
- can reduce tourism
109
causes of increased extreme weather in uk
- climate crisis/change
- sea temp. rises
- avg. global temp. is higher
- stronger winds
- warm ocean current from caribbean crosses atlantic bringing warm air
- gulf stream affected by warming artic leading to uk freezing
110
what is happening to extreme weather in the uk
more intense and more frequent
111
evidence of increased extreme weather in uk
- roads melting
- leaves fall earlier and grow first
- ecosystems out of sync
- rails unbuckling
- train cancellations
- heavy rain
- higher avg. temp.
- more hours of sunlight
- sea level rise doubles in the last century
112
causes of somerset floods
- from dec 2013 - feb 2014, 3x avg. rainfall
- lots of rain fell on saturated ground and coincided w/ high tides and storm surges => extensive flooding
- river hadn’t been dredged regularly for 20 years > reduced capacity
113
social impacts of somerset floods
- more than 600 homes flooded and many people forced to evacuate
- villages cut off by road and only way in or out was by boat
- major transport links (A361, train lines) closed or disrupted
- insurance prices soared and some residents unable to insure homes against future flooding
114
environmental impacts of somerset floods
- 11,500 hectares flooded, incl. farmland > destroyed crops
- standing water made ground toxic and unproductive for over a year > loss of nutrients and date to soil structure decreased fertility
- tonnes of mud and debris left by flood > damaged vegetation
115
economic impacts of somerset floods
- total cost of damage was over £80 mil
- local companies lost more than £1.2 mil in business
- loss of tourism cost country more than £200 mil
116
immediate responses to the somerset floods
- warning systems gave people time to prepare e.g. met office warned people to find emergency accom
- individuals and local authorities used sandbags and flood boards to try limit flood damage
117
long term responses to the somerset floods
gov set up ‘somerset levels and moors flood action plan’ - a 20 year plan whcih aims to limit the risk of future flooding. £100 mil will be spent on:
- turning temporary pumping stations into permanent ones
- regular dredging of rivers
- building a tidal barrage
- widening river sowy’s channel and king’s sedgemoor drain
118
what are three causes of natural climate change
1. solar energy output
2. orbital changes
3. volcanic activity
119
what is solar energy output and how does it cause climate change
- sunspots are dark spots on suns surface that radiate out more energy making the earth warmer
- they follow an irregular cycle that lasts ab 11 years
- we currently have had 50 years of low solar activity
120
what is orbital changes and how does it cause climate change
- earths orbit can fluctuate between elliptical and circular over courses of 95k years
- means that at some points during orbit the distance to sun varies so we receive more or less energy
- every 21k years earth wobbles on its axis
- earths axis is tilted on an angle
- angle fluctuates due to gravitational pull of the moon every 42k years
121
what is volcanic activity and how does it cause climate change
- major volcanic eruptions lead to a brief period of global cooling
- toba catastrophe 70k yrs ago - perhaps 30k humans left
- most recent explosion to have similar effect was pinatubo (1991), sunlight reaching earth was reduced by 10%, world temp. fell by 0.5˚C the following year
122
what is global dimming
when an ash cloud blocks the amount of light reaching earths surface causing a drop in temp.
123
what are human causes of climate change
factories, transport, burning of fossil fuels
124
what do scientists agree as the current cause of global warming
enhanced greenhouse effect - man made - global warming
125
what are the 2 ways of coping w/ climate change
1. mitigation
2. adaptation
126
define mitigation
aims to reduce the cause of the problem by limiting or preventing GHGs and protecting carbon sinks
127
define adaptation
responds to the impacts of climate change and tries to make people less vulnerable
128
is wind and solar energy mitigation or adaptation
mitigation
129
how does wind/solar energy reduce climate change
renewable sources of energy do not produce CO2 so there is less CO2 in the atmosphere so GHG layer doesn’t thicken
130
fact or example of wind/solar energy
in 2022, 36% of uk’s electricity was generated using renewables
131
assessment of using wind/solar energy as a mitigation strategy
- good but they are more expensive than FFs although they are coming down in price
- if there is no wind or sun you need an alternative source
132
is carbon capture a mitigation or adaptation strategy
mitigation
133
how does carbon capture reduce climate change
catches CO2 emitted by power stations and industrial facilities so less goes into the atmosphere
134
fact or example ab carbon capture
there are currently only 35 facilities using CCS. ambitions for over 200 new facilites by 2030
135
assessment of carbon capture as a mitigation strategy
v. expensive and uses lots of energy
136
is planting trees a mitigation or adaptation strategy
mitigation
137
how does planting trees reduce climate change
trees absorb CO2 and convert it into solid carbon
138
fact/example ab planting trees
uk has a £24.9mil project to reduce deforestation + increase forest land restoration in brazil
139
assessment of planting trees as a mitigation strategy
v. good
140
is international agreements a mitigation or adaptation strategy
adaptation
141
how does international agreements help people adapt to climate change
- cop 26 summit brought parties together to accelerate action towards the goals of the paris agreement.
- agreements to reduce CO2
- carbon trading
142
fact or example ab international agreements
paris agree to is a legally binding international treaty on climate change. it was adopted by 196 parties.
143
assessment of international agreements as an adaptation strategy
targets aren’t sufficiently challenging
144
are changes in farming a mitigation or adaptation strategy
adaption
145
how does changes in farming help people to adapt to climate change
in bangladesh, floating gardens made of water hyacinths as they aren’t affected by flooding so crops aren’t destroyed > reduces poverty and hunger
146
fact or example ab changes in farming
according to FAQ the farmers earn average $140/100sqm
147
assessment of changes in farming as an adaptation strategy
helps solve flooding, poverty and hunger
148
is managing water supply a mitigation or adaptation strategy
adaptation
149
how does managing water supply help people adapt to climate change
dripping water instead of spraying it so conserves water
150
fact or example ab managing water supply
hydroponics use 10 times less water than if you were growing it in the ground
151
assessment of managing water supply as an adaptation strategy
increases efficiency
152
is reducing risk from sea level rise a mitigation or adaptation strategy
adaptation
153
how does reducing risk form sea level rise help people adapt to climate change
adapting to sea levels rising reduces flood damage
154
fact/example ab reducing risk form sea level rise
thames barrier has been closed 200 times to prevent flooding
155
assessment of reducing risk form sea level rise as an adaptation strategy
v. expensive
