P1 - Unit 1A - Natural hazards Flashcards
(108 cards)
1
Q
What are the characteristics of the Oceanic crust?
A
Denser Thinner Can be renewed Can be destroyed Younger
2
Q
What are the characteristics of the Continental crust?
A
Less dense Can't be renewed Can't be destroyed Older Thicker
3
Q
Define: epicentre
A
The point directly above the focus on the surface of the earth
4
Q
Define: focus/hypocenter
A
The point within the earth where the earthquake rupture starts
-near the focus shock waves are stronger and cause more damage
5
Q
What happens at a destructive plate boundary?
A
- when you have oceanic and continental plates moving towards each other
- The oceanic plate is sub-ducted because it’s denser
- friction between the plates cause earthquakes
- heat in the earth melts the oceanic plate creating magma
- the magma then creates a composite volcano
-when you have two continental plates, they collide and the ground is folded and forced upwards to create a mountain range
6
Q
What is the location of tropical storms?
A
Tropical storms occur in areas of low pressure within the tropics between latitudes 5° and 20° north and south of the equator.
7
Q
What are the conditions required for a tropical storm?
A
- water temperature greater than 27°C
- water at least 70m deep
- low pressure
- over water
- when the wind sheer(difference in windspeed) between the higher and lower parts of the atmosphere is low
8
Q
How does a tropical storm form?
A
1) Water evaporates from the ocean surface and comes into contact with a mass of cold air, forming clouds.
2) A column of low pressure develops at the centre. Winds form around the column.
3) As pressure in the central column(the eye) weakens, the speed of the wind around it increases.
9
Q
Why do tropical storms lose energy?
A
As hurricanes move inshore, their power gradually reduces because their energy comes from sucking up moist warm sea air.
10
Q
What are the primary effects of tropical storms?
A
- buildings collapsing
- deaths
- storm surges flooding areas
- crops destroyed
- injuries
11
Q
What are features of tropical storm shelters?
A
- shutters-so don’t have shards of broken glass
- building on stilts-storm surges can’t affect, flooding can’t affect
- built on raised ground-prevents house flooding
- made of strong concrete-withstand tropical storm
- siren-to warn people
12
Q
What happens at a constructive plate boundary and what can be caused by it?
A
- when two plates move apart
- you can find shield volcanoes and ocean ridges
13
Q
What happens at a conservative plate boundary and what can be caused by it?
A
- two plates move side by side
- you can find earthquakes, faults
14
Q
What happens at a destructive plate boundary and what can be caused by it?
A
- two plates move towards each other
- you can find composite volcanoes, earthquakes, ocean trenches
15
Q
Define natural hazard:
A
An extreme natural event that has the potential to cause loss of life and/or extreme damage to property and creates severe disruption to human activities.
16
Q
Define hazard risk:
A
The probability or chance that a natural hazard may take place
17
Q
Define natural disaster:
A
The realisation of a hazard with consequences
18
Q
What are examples of meteorological hazards?
A
-caused by weather and climate Heatwaves Drought Storms Tornado Hurricane Flood
19
Q
What are examples of geological hazards?
A
-caused by land and tectonic processes Volcanoes Earthquakes Tsunami Rockfall Landslide Avalanche Flood
20
Q
What factors make hazards more dangerous to people?
A
Education Location HIC/LIC Climate Physical geography Population density Proximity to ocean Level of development Type of natural hazard (frequency and magnitude of it)
21
Q
What are the layers of the earth?
From inside to out
A
- inner core
- outer core
- mantle
- crust
22
Q
What is continental drift?
A
The gradual movement of the continents across the earths surface through geological time
23
Q
Describe the distribution of earthquakes:
A
- found in long narrow belts along plate boundaries
- earthquakes are found in the middle of the Atlantic Ocean following the mid Atlantic ridge
24
Q
Describe the distribution of volcanoes:
A
- volcanoes occur in narrow belts or small clumps called hot spots
- one belt round the Pacific Ocean and is called the ring of fire
25
Define volcano:
A volcano is an vent or fissure in the earths crust through which molten rock and hot gases escape to the surface during an eruption.
26
What are characteristics of composite volcanoes?
- found at destructive plate boundary
- have steep sides, cone shaped
- made up of alternative layers of ash and lava
- acidic lava
27
What are characteristics of shield volcanoes?
- constructive plate boundaries
- have a wide base and gently sloping sides
- basaltic lava
28
How are earthquakes measured?
The moment magnitude scale
- it measures the magnitude (amount of energy released by the earthquake)
- it is logarithmic, so a magnitude 7 is ten times as powerful as a magnitude 6
29
What were the primary effects of the Haiti earthquake?
```
220,000 people died on impact
105,000 homes destroyed
Presidential palace and Port-Au-Prince Cathedral damaged
80% of schools were damaged
Airport damaged
300,000 people injured
```
30
What were the secondary effects of the Haiti earthquake?
$14 billion damage costs
1.5 million people made homeless
Cholera outbreak in October 2010
1.5 million people living in camps
31
What were the primary effects of the Christchurch, New Zealand earthquake?
185 people died
6000 injured
CTV building collapsed
50% of central city building were damaged
32
What were the secondary impacts of the Christchurch, New Zealand earthquake?
3.5m tsunami
Landslides in Lyttelton
Rugby World Cup moved to other locations
Buildings were demolished because they were deemed unsafe
33
What are some general facts about hurricane Katrina?
August 2005
In New Orleans
Struck Mississippi and Louisiana
Katrina got to a Category 5 status in the Caribbean
-In New Orleans the effects were particularly severe because the flood defences failed
34
What were the primary effects of hurricane Katrina?
- Super Bowl roof broke
- 1800 people died
- bridges collapsed, twin span bridge
- 80% of the city flooded
- 300,000 houses were destroyed
- 3 million people were left without electricity
- coastal habitats damaged
35
What were secondary effects of hurricane Katrina?
- oil spills
- industrial waste and toxic chemicals in water (water supply polluted)
- fall in trade business, tourism
- $150 billion cost of damage
- hundreds of thousands of people left homeless
- 230000 jobs were lost from damaged buisnesses
36
What were the immediate responses to hurricane Katrina?
- 70% of New Orleans residents were evacuated before it reached land
- Mississippi and Louisiana declared states of emergency (set up control centres, emergency shelters and stockpiled supplies)
- coastguard, police, fire service and army rescued over 50000 people
- charities collected donations and supplied aid, including millions of hot meals
37
What were the long term responses to hurricane Katrina?
- US government provided over 16 billion dollars for the rebuilding of homes and other essential infrastructure
- US army recommended that in low lying areas houses were re-built on stilts or not re-built at all
- repaired and improved flood defences for New Orleans costing 14.5 billion dollars (completed 2013)
38
What are the three main management strategies for reducing the risk from weather hazards?
Prediction-using satellites and aircrafts
Protect-designing buildings to withstand it
Prepare-raise awareness in places most at risk from tropical storms
39
What are the two categories of natural hazards?
geological hazard
| meteorological hazard
40
What is the core of the earth made up of?
A ball of solid(inner) and liquid(outer) iron and nickel
41
What is the mantle?
semi-molten rock which moves very slowly
42
What are the two types of tectonic plate which the crust is divided into?
continental
| oceanic
43
What causes plates to move?
Convection currents
44
What are the points which plates meet are called?
plate margins/boundaries
45
How are volcanoes formed at destructive plate boundaries?
- the oceanic is subducted towards the mantle, where it is melted and destroyed
- a pool of magma forms
- magma rises through cracks in the crust called vents
- magma erupts on the surface(where it is called lava) forming a volcano
46
How are volcanoes formed at constructive plate boundaries?
-magma rises up into the gap created by the plates moving apart, forming a volcano
47
What are hotspots?
Parts of the mantle which are really hot (e.g. Hawaii)
48
What happens when a volcano errupts?
- it emits lava and gases
| - some volcanoes emit lots of ash which can cover land, block out the sun and form pyroclastic flows
49
What is a pyroclastic flow?
super-heated currents of gas, ash and rock
50
How do earthquakes occur at destructive plate boundaries?
- tension builds up when one plate gets stuck as it is moving down past another
- the plates eventually jerk past each other, sending out shock waves (these vibrations are called an earthquake)
51
How do earthquakes occur at constructive plate boundaries?
- -tension builds along cracks within the plates as they move away from each other
- the plates eventually jerk past each other, sending out shock waves (these vibrations are called an earthquake)
52
How do earthquakes occur at conservative plate boundaries?
- tension builds up when plates are grinding past each other and one gets stuck
- the plates eventually jerk past each other, sending out shock waves (these vibrations are called an earthquake)
53
What will a <6 magnitude earthquake cause?
-normally only cause slight damage to buildings, although they can be worse in built up areas
54
What will a >7 magnitude earthquake cause?
-major damage and deaths
55
What are the primary effects of earthquakes?
- buildings and bridges collapse, homes are destroyed
- people are injured or killed by collapsed building or falling debris
- roads, railways, ports and airports are damaged
- electricity cables, gas and water pipes and communications networks are damaged, cutting off supplies
56
What are the secondary effects of earthquakes?
- earthquakes can trigger landslides and tsunamis, this destroys more buildings, causes more injury and death
- leaking gas can be ignited starting fires
- people are left homeless and could die
- shortage of clean water and lack of proper sanitation (easier for diseases to spread)
- block or destroyed roads means aid and emergency vehicles can't get through and trade is difficult
- businesses are destroyed or damaged, causing unemployment and lost income (tourists can also be put off visiting the area)
- repairs and reconstruction can be very expensive, weakening a country's economy
57
What are the immediate responses to earthquakes?
- rescue of people trapped by collapsed buildings, and treatment to injured people
- recover dead bodies to prevent the spread of disease
- put out fires
- temporary shelters set up
- temporary supplies of water, food, electricity, gas and communication systems (if they have been damaged)
- foreign governments or charities may send aid workers, supplies, equipment, financial donations
58
What are the long term responses to earthquakes?
- re-house people who lost their homes
- repair or rebuild buildings, roads, railways and bridges
- reconnect electricity, water, gas and communication centres
- if necessary, improve building regulations so more building are resistant to damage from earthquakes
- set up initiatives to help economic recovery
59
What are the primary effects of volcanoes?
- buildings and bridges collapse, homes are destroyed by pyroclastic flows
- people and animals are injured or killed by pyroclastic flows, lava flows and falling rocks
- crops are damaged and water supplies are contaminated when ash falls on them
- people, animals and plants are suffocated by volcanic gases
60
What are the secondary effects of volcanoes?
- mudflows form when volcanic material mixes with water, cause more destruction, death and injury
- flooding can be caused by hot rock, ash and gas melting ice and snow on the volcano, rock and ash can clog up rivers making flooding worse
- transport networks are destroyed or blocked so aid and emergency vehicles can't get through
- people left homeless (destroyed businesses causes unemployment)
- tourism can be disrupted straight after an eruption, but often can increase after with tourists interested in seeing volcanoes
- ash makes field more fertile, once broken down
- recovering takes a huge amount of money
61
What are the immediate responses to volcanoes?
- evacuate people
- provide food, shelter and water for evacuated people
- treat injured people
- rescue anyone cut off by damage to roads or bridges
- provide temporary supplies of electricity, gas and communications systems
- foreign governments or charities may send aid workers, supplies, equipment or financial support
62
What are the long term responses to volcanoes?
- re-house people who lost their homes
- repair or rebuild buildings, roads, railways and bridges
- reconnect electricity, water, gas and communication centres
- improve, repair and update monitoring and evacuation plans
- set up initiatives to help economic recovery
63
Why do people live in areas which are at rick from tectonic hazards?
- always lived there (don't want to be away from family)
- employed in the area
- confident in the support from their government
- some people think events won't happen again
- soil around volcanoes are very fertile (attract farmers)
- volcanoes are tourist attractions, jobs available in the tourist industry
64
What are the different management strategies that are used to reduce the effects of tectonic hazards?
monitoring
prediction
protection
planning
65
How can monitoring be a management strategy to reduce the effects of tectonic hazards?
- networks of seismometers and lasers monitor the earth's movement, used in early warning systems to give a small but vital amount of warning
- scientists can monitor the tell-tale signs that come before a volcanic eruption (escaping gas, changing shape)
66
How can prediction be a management strategy to reduce the effects of tectonic hazards?
- earthquakes aren't easy to predict, but by monitoring plate movement, scientists can predict which areas should be prepared
- volcanic eruptions can be predicted is it is well monitored, this gives people time to evacuate
67
How can protection be a management strategy to reduce the effects of tectonic hazards?
- building can be designed to withstand earthquakes
- existing buildings and bridges can be strengthened so they are less likely to collapse
- automatic shut-off systems can be fitted that turn off the gas and electricity supplies to prevent fires
68
How can planning be a management strategy to reduce the effects of tectonic hazards?
- future developments can be planned to avoid the areas most at risk from tectonic hazards
- emergency services can train and prepare people for disasters
- people educated to know what to do
- governments can plan evacuation routes to get people out of dangerous areas quickly and safely
- emergency supplies can be stockpiled
69
What are winds?
Large scale movements of air caused by differences in air pressure
70
What are differences in air pressure caused by?
Differences in temperature between the equator and the poles (winds move from areas of high pressure to areas of low pressure)
71
What do the global atmospheric circulation loops contain?
- warm rising air which creates a low pressure belt
- cool falling air which creates a high pressure belt
causes areas to have some types of weather more than others
72
What is the air pressure like at the equator?
-the sun warms the earth, which transfers heat to the air above causing it to rise
LOW PRESSURE BELT with rising air, clouds and rain
73
What is the air pressure like at 30 degrees north and south of the equator?
-cool air sinks
HIGH PRESSURE BELT with cloudless skies and very low rainfall
-when the cool air reaches the ground surface winds either occur towards the equator or the poles
74
What is a trade wind?
Winds blowing toward the equator
| -they meet at the equator and are heated by the sun and rise to form clouds
75
What is a westerlie?
Winds blowing toward the poles
76
What is the air pressure like at 60 degrees north and south of the equator?
-the warmer surface winds meet colder air from the poles
-the warmer air is less dense so it rises
LOW PRESSURE
77
What is the air pressure like at the poles?
-cool air sinks
HIGH PRESSURE
-air is drawn back to the equator as surface winds
78
How do tropical storms form?
- warm, moist air rises and condensation occurs
- this releases huge amounts of energy which makes storms powerful
- rising air creates an area of low pressure which increases surface winds
- the earths rotation deflects the paths of the winds, causing the storm to spin
- the storm gets stronger and stronger due to the energy from warm water
79
What direction do tropical storms travel?
-move towards the west because of easterly winds near the equator
80
What happens when tropical storms go over land?
lose strength when they move over land or cooler water because the energy supply from the warm water is cut off
81
Describe the location of tropical storms:
- between 5 and 30 degrees north and south of the equator (majority in the northern hemisphere)
- in late summer and autumn they occur most when sea temperature is the highest
82
What are general features of a tropical storm?
- circular in shape
- hundreds of kilometres wide
- last 7-14 days
- spin anticlockwise in the northern hemisphere
- spin clockwise in the southern hemisphere
83
What are some structural features of a tropical storm?
```
the eye (the centre of the storm)
eyewall (what surrounds the eye)
```
84
What are the features of the eye?
- up to 50km across caused by descending air
| - low pressure, light winds, no clouds, no rain and a high temperature
85
What are the features of the eyewall?
-spiralling rising air, very strong winds, storm clouds, torrential rain, low temperature
86
What affect will climate change have on tropical storms?
- since global temperatures are rising, more of the worlds oceans will be above 27°C so more places will experience tropical storms
- oceans will stay at 27°C or above for more of the year so the number of tropical storms each year could increase
- storms could also be stronger from the higher temperature
87
What are the primary effects of tropical storms?
- building and bridges destroyed
- river and coastal areas flood
- people drown, are injured or killed by debris that is blown around
- roads, railways, ports and airports are damaged
- electricity cables damaged
- sewage overflows due to flooding (sewage contaminates water supplies)
88
What are the secondary effects of tropical storms?
- people left homeless
- shortage of clean water and lack of proper sanitation
- roads are blocked or destroyed so aid and emergency vehicles can't get through
- businesses get damaged or destroyed causing unemployment
- shortage of food (crops damaged, livestock killed, supply lines blocked)
89
What are the immediate responses to tropical storms?
- evacuate people before the storm arrives
- rescue people
- set up temporary shelters
- provide temporary supplies of water, food, electricity, gas and communication systems
- recover dead bodies to prevent the spread of disease
- foreign governments or NGOs may send aid workers, supplies, equipment or financial donations
90
What are the long term responses to tropical storms?
- repair homes or rehouse people
- repair or replace damaged infrastructure
- repair and improve flood defence systems
- improve forecasting techniques to give people more warning
- provide aid, grants and subsidies to residents to repair and strengthen homes
- promote economic recovery and encourage people to return (e.g. tax breaks)
- improve building regulations so more buildings withstand hurricanes
91
What are the three strategies to reduce the effects of tropical storms?
prediction
planning
protection
92
How can prediction reduce the effects of tropical storms?
- scientist use data collected from satellites to create computer models that calculate a predicted path for the storm
- prediction GIVES PEOPLE TIME to evacuate and protect their homes and businesses
93
How can planning reduce the effects of tropical storms?
- future developments can be planned to avoid the areas that are most at risk
- emergency services can train and prepare for disasters
- governments can plan evacuation routes to get people away from storm quickly
94
How can protection reduce the effects of tropical storms?
-building can be designed to withstand tropical storms
-flood defences can be built along rivers and coasts
(all reduce the number of buildings destroyed so fewer people will be killed, injured, made homeless or unemployed)
95
What are the different weather hazards in the UK?
```
rain
wind
snow and ice
thunderstorms
hailstorms
heat waves
drought
```
96
What are the factors of rain as a weather hazard in the UK?
| And what effects do this weather hazard have on the UK?
- too much rain in a short amount of time can cause flooding (can damage homes and possessions, disrupt transport networks and cause deaths by drowning)
- flooding forces businesses to close and recovering from flooding can cost millions of pounds
97
What are the factors of wind as a weather hazard in the UK?
| And what effects do this weather hazard have on the UK?
- strong winds can damage properties and disruption to transport
- uprooted trees and debris can injure or kill people
- forests can be damaged when trees are knocked over
- winds are strongest in coastal areas and in upland areas
98
What are the factors of snow and ice as a weather hazard in the UK?
And what effects do this weather hazard have on the UK?
- cause injuries due to slipping and deaths due to the cold
- schools and businesses can be forced to shut, major disruption to road, rail and air travel can cause economic impacts
- cold snaps can damage crops
99
What are the factors of thunderstorms as a weather hazard in the UK?
And what effects do this weather hazard have on the UK?
- heavy rain, lightning and strong winds occur in a thunderstorm
- common in the summer in the south east of the UK
- lightening can cause death, and fires that damage property and the environment
100
What are the factors of hailstorms as a weather hazard in the UK?
And what effects do this weather hazard have on the UK?
-make driving very dangerous and can damage and destroy crops
101
What are the factors of drought as a weather hazard in the UK?
And what effects do this weather hazard have on the UK?
- drought is lack of precipitation
- water supplies can run low causing economic impacts such as loss of crops, rules to conserve water have to be introduced
102
What are the factors of heat waves as a weather hazard in the UK?
And what effects do this weather hazard have on the UK?
- long periods of hot weather
- can cause deaths from heat exhaustion or difficulties breathing as pollution builds up in the air
- disruption to transport from rails buckling or roads melting can cause economic impacts (tourism industry may benefit from better weather though)
103
What is happening to the weather in the UK?
- temperatures have become more extreme
- it is raining more
- major flooding occurs more often
104
What is the named example of an extreme weather event which occurred in the UK?
Cockermouth flooding 2009
- 12 inches of rain in 24 hours
- cockermouth is in Cumbria
- occurred because of the low pressure weather system, and the hills increases surface run off and the ground was already saturated before hand
105
What were the social impacts of the cockermouth flood in 2009?
- police officer died from a bridge collapsing
- people becoming homeless
- schools closed
106
What were the economic impacts of the cockermouth flood in 2009?
- bridge collapsed
- one pub got extra businesses because the other pubs were flooded
- businesses flooded and so people loose jobs
107
What were the environmental impacts of the cockermouth flood in 2009?
- geese needed to be moved
- farmland flooded
- farmland covered in bedload
- the land was flooded
108
What management strategies can raduce the risks from weather hazards?
prediction - warning systems giving people more time
protection - individuals and local authorities prepare for the extreme weather before it happens
planning - emergency services and local councils plan how to deal with the event
