Hazardous Environments Flashcards
1
Q
Types of Hazards
What is a hazard?
A
Ahazardis an event which has the potential to cause harm to the environment, people or the economy
2
Q
What is a natural hazard?
A
event caused by environmental processes
3
Q
What is a disaster?
A
disasteroccurs when harm actually occurs to the environment, people or the economy
4
Q
What is a natural disaster?
A
Damage and destruction caused by a physical event such as an earthquake.
5
Q
What are the 4 causes that can be used to categories natural hazards?
A
Tectonic & Geological
Climatic & Meteorological
Biological
Technological
6
Q
Give example of 2 tectonic natural hazards:
A
Earthquake, volcanic eruption and tsunami
7
Q
Give example of 2 Climatic natural hazards:
A
Storms, Floods, Droughts and Tornadoes
8
Q
Give example of 2 Biological natural hazards:
A
Pests and Diseases
9
Q
What other ways can natural hazards be categorised?
A
Magnitude- Strength/Power of event
Frequency- how often the event occurs
Size- area covered by hazard
Duration- time a hazard event lasts
Location- where it occurs
10
Q
What is a tropical cyclone?
A
Tropical cyclones are rotating, low pressure systems (below 950mb)
They are known ashurricanes, cyclonesandtyphoonsin different areas of the world
11
Q
What are the characteristics of a tropical cyclone?
A
Heavy rainfall
High wind speeds (Over 119kmph)
High waves and storm surges
Calm eye at center.
12
Q
How is the magnitude of a tropical cyclone measured?
A
Saffir-Simpson Scale from 1 to 5
13
Q
Explain the distribution of a tropical cyclone:
A
They develop in tropical regions between 5 and 30 degrees north and south of the equator.
14
Q
What is an earthquake?
A
A sudden violent shaking of the ground. Earthquakes are the result of pressure building when tectonic plates move.
15
Q
What is the epicentre?
A
The point on the Earth’s surface directly above the focus.
16
Q
What is the focus?
A
The point at which the earthquake starts below the Earth’s surface.
17
Q
How is the magnitude of an earthquake measured?
A
Richter Scale
18
Q
How is the damage of an earthquake measured?
A
Mercalli Scale
19
Q
Explain the distribution of earthquakes:
A
- Earthquakes are found at all types of plate margins.
- Earthquakes can occur anywhere there is a fault or weakness in the crust.
- There is an ‘earthquake belt’ around the world where plate activity gives rise to earthquakes.
- This belt is most noted in a circle around the Pacific Ocean, known as the Pacific Ring of Fire
- Also seen in a line through the Mid Atlantic Ridge.
20
Q
What is a volcano?
A
- When magma erupts onto the Earth’s surface as lava.
- An opening in the earth’s crust through which lava, volcanic ash and gases escape.
21
Q
How is the magnitude of a volcanic eruption measured?
A
Volcanic Explosivity Index (VEI)
22
Q
What is a hotspot?
A
Hotspots occur away from plate boundaries and are plumes/columns of magma which escape the earth’s crust
23
Q
Explain the distribution of volcanoes:
A
Most volcanoes occur at constructive and destructive plate boundaries.
The majority of active volcanoes are located around the rim of the Pacific Ocean called the ‘Ring of Fire’.
24
Q
Tropical Cyclones
What are the causes of tropical cyclone hazards?
A
- Low-pressure areas (less than 950mb)
- Between 5° and 20° north and south of the equator
- Low wind shear
- A deep layer of humid air
25
What are the stages of tropical cyclone formation?
- Warm, moist air rapidly rises forming an area of low pressure
- Air from high-pressure areas rushes in to take the place of the **rising air**
- This air then rises forming a continuous flow of rising air
- As the air rises it cools and condenses. This releases heat energy which helps to power the tropical cyclone
- Air at the top of the storm goes outwards away from the centre of the storm
- The **Coriolis force** causes the rising air to spiral around the centre.
- Some of the air sinks in the middle of the storm forming the **cloudless, calm eye**.
- The tropical cyclone moves **westwards** from its source
- When a tropical cyclone makes landfall or moves over an area of cold water it no longer has a supply of warm, moist air and it loses speed and temperature. Rainfall and winds decrease
26
What are the features of Tropical Cyclones?
- Heavy rainfall
- High wind speeds (over 74kmph)
- Storm surges
- Calm eye
- Highest winds and heaviest rain the wall of the eye
- Diameter up to 800km
27
What is wind shear?
Sudden changes in wind speed and/or direction.
28
What is the coriolis force?
The invisible force that appears to deflect the wind. The coriolis force applies to movement on rotating objects.
29
What is the coriolis effect?
Describes the pattern of deflection taken by objects not firmly connected to the ground as they travel long distances around the earth.
30
# Tectonic Hazards
What is a plate boundary?
Border between 2 tectonic plates.
31
What are the 4 main types of plate boundaries?
Constructive, Destructive, Collision and Conservative
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What is a constructive plate boundary?
At a constructive plate boundary, the plates are moving apart.
The Mid Atlantic Ridge is an example of a constructive plate boundary.
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What is a destructive plate boundary?
At a destructive plate boundary, the plates are moving together.
The denser, heavier oceanic plate subducts under the lighter, less dense continental plate.
The boundary between the Nazca plate and South American Plate is an example.
34
What is a collision plate boundary?
At a collision plate boundary, two plates of similar density move towards each other.
Neither is dense enough so subduct so the land is pushed upwards.
This forms fold mountains such as the Himalayas.
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What is a conservative plate boundary?
At a conservative boundary the plates move passed each other in opposite directions or in the same direction at different speeds.
36
What plate boundaries to volcanoes occur at?
Volcanoes occur at constructive, destructive plate boundaries and hot spots.
They do NOT occur at conservative or collision.
37
What are shield volcanoes?
Shield volcanoes are broad volcanoes with gentle slopes.
38
How are volcanoes formed at constructive boundaries?
Constructive plate boundaries often occur under the sea/ocean.
Lava escapes through the gap left as plates move apart.
The lava cools and hardens forming a new crust.
At constructive plate boundaries, lava tends to be runny and eruptions are less explosive.
These types of eruptions formed shield volcanoes.
39
How are volcanoes formed at destructive boundaries?
The heavier, denser oceanic plate subducts under the lighter continental plate.
In the subduction zone, the 2 plates come together causing friction.
Friction causes heat and the plate material melts forming magma.
The magma rises to the surface through cracks in the crust.
The cooling lava and ash build up forming a volcano.
Eruptions at destructive plate boundaries tend to be explosive eruptions.
These eruptions tend to form composite or stratovolcanoes.
40
How are volcanoes formed at hotspots?
At a hotspot, the tectonic plate passes over a plume of magma.
The magma rises to the surface through cracks in the crust.
As the tectonic plate moves slowly over the magma plume, a line of islands my form e.g. Hawaii.
41
What are the primary hazards of volcanoes?
Ash
Pyroclastic flow
lava flow
gas emissions
volcanic bombs
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What is pyroclastic flow?
Clouds of superheated material up to 700 degrees centigrade which can travel up to 500kmph.
42
What are the secondary hazards of volcanoes?
Lahars
Acidification
Landslides
Climate Change
Fires
43
What is a lahar?
When water(often from melting snow and ice) mixes with volcanic ash to create a fast moving mudflow.
44
What is acidification?
Sulphur emissions from volcanic eruptions increase the acidity of water.
45
What plate boundaries to earthquakes occur at ?
Earthquakes happen at all plate boundaries.
They can occur anywhere but mostly occur at or near plate boundaries.
46
Which plate boundaries produce the strongest earthquakes?
Destructive, collision and conservative.
47
What are the primary hazards of earthquakes?
Ground shaking
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What are the secondary hazards of earthquakes?
Collapse of buildings and other structures.
Landslides
Mudflows
Tsunamis
Subsidence- Sudden sinking of the Earth’s surface.
49
Explain the sequence of an earthquake occurrence:
The sequence of an earthquake is the same regardless of the boundary it occurs on.
- As tectonic plates move, they get stuck
- Pressure builds as the plates continue to try to move.
- Eventually, the plates jolt free and the pressure is released as energy.
- The point at which the earthquake starts is the focus.
- Energy passes through the Earth’s crust as waves which is the earthquake.
50
# Living in Hazardous Areas
What are the main reasons for living in hazardous regions?
- A lack of education and information means people may not be aware of the risks.
- The advantages of living in the area outweighs the disadvantages- fertile soil, geothermal energy, access to water, trade, jobs tourism.
- People cannot afford to move away due to little income.
- People were born in an area and don’t want to move away from family/friends as they have an emotional attachment there.
51
# Vulnerability to Natural Hazards
What are the factors affecting the vulnerability of countries to natural hazards?
Economic
Social
Physical
52
Give examples of economic factors affecting vulnerability of countries to natural hazards:
**Wealth and Level of Development:** quality of buildings, healthcare and infrastructure all depend on the wealth of a country or area.
**Insurance:** People living in poverty cannot afford insurance and insurance companies will only insure well-built homes/ structures.
**Buildings:** Planning controls, poverty, building styles and the quality of materials all affect the safety of buildings.
**Technology:** Wealthier countries will have more access to monitoring equipment so they may get more warning of events.
53
Give examples of social factors affecting the vulnerability of countries to natural hazards:
**Population Density:** the more people there are in an area, the higher numbers of deaths and injuries are likely to be. High population density also means housing density is also more compact.
**Education:** People with a higher level of education are likely to be wealthier and be able to afford better-quality housing. Levels of education also affect how informed people are about the risks.
54
Give examples of physical factors affecting the vulnerability of countries to natural hazards:
**Global Location:** Some areas experience more hazards because they are near plate boundaries or in tropical regions.
**Physical Environment:** Steep slopes can increase the chances of landslides and coastal areas are more vulnerable to storm surges and tsunamis.
55
# Impacts of Natural Hazards
What are some short term impacts of natural hazard events?
- Damage to properties from high wind, heavy rain and storm surges, power cables and telephone lines.
- Impact on businesses, tourism and transport
- Landslides
- Deaths and injuries, decrease in quality of life.
- Crops destroyed, impacting on farmers incomes and increasing food prices.
- Habitat destruction.
56
What are some long term impacts of hazard events?
- Rebuilding of homes, schools, infrastructure can take time.
- The cost of rebuilding affects the economy, increases unemployment
- Stricter building codes introduced.
- Mental health, PTSD
- Risk assessment and hazard mapping reviewed.
57
# Preparing for Earthquakes
What are the different methods of monitoring being used to help research possible prediction methods?
Tiltmeters
Clusters of small earthquakes
Changes in radon gas emissions
Changes in animal behaviour
Remote sensing of ground movement using satellites
58
What is a tiltmeter?
An instrument used to measure slight changes in the inclination of the earth's surface
59
What are the different ways countries can prepare for earthquakes?
- Building design and earthquake resistant structures
- Land use planning
- Earthquake drills
- Emergency Planning
60
Explain the importance of building design to prepare for earthquakes
More commonly used in developed countries as they can afford this.
Building regulations and codes require new buildings to include earthquake-resistant features:
- Shutters on windows prevent falling glass
- Cross-bracing of steel frames
- Foundations sunk deep into bedrock
- Frames which sway with the earthquake tremors
- Rubber shock absorbers to reduce tremors moving through the building.
61
Explain the importance of Land Use Planning to prepare for earthquakes:
* 1. * - Mapping of areas most at risk from earthquakes.
* 1. * - Planning can ensure that valuable services such as the fire service and hospitals are not built in high-risk areas.
* 1. * - Densely populated housing can be located away from high-risk areas.
62
Explain the importance of Drills and Education to prepare for earthquakes:
- In many countries earthquake drills are regularly carried out.
- The drills help people to prepare for what to do in an earthquake to protect themselves.
- Education about how to prepare homes means that people are less likely to be injured by falling objects and furniture.
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What is Remote Sensing?
Remote sensing of the Earth’s surface by satellites provides data about changes in ground movement.
64
What is GIS?
- Geographic Information Systems (GIS) provides layers of data such as:
- Vulnerable areas
- Land use
- Infrastructure such as roads
- GIS data is then used to assist with land use planning.
65
# Response to Earthquakes
hat is emergency response (Earthquake) ?
The emergency response are the actions taken immediately after a hazard event such as an earthquake.
66
Give examples of emergency responses after an earthquake:
- Searching collapsed buildings to rescue people who are trapped
- Providing medical assistance.
- Distribution of food and water.
- Ensuring that people have shelter
- Clearing rubble and other debris
67
# Planning To Loag term
What is the role of long term planning?
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What questions may be asked before planning long term?
- Was emergency aid distributed effectively?
- Are there areas which are at particular risk should they be protected more or buildings moved?
- Could warning systems be moved.
- Are people educated about the risks and know what to do to better protect themselves?
- Can building codes and planning be improved to reduce the number of collapsing buildings?
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What are the parts of the long-term planning process?
Risk assessment, hazard mapping and rebuilding programmes.
70
What is risk (natural hazards)?
- Risk is the probability that a hazard event will have harmful consequences.
- The more vulnerable a population is, the greater a risk that a hazard event will cause death, injuries, damage to buildings and impact the economy.
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How does risk assessment play a role in long term planning?
- Risk assessment helps in long term planning by identifying and assessing the likelihood and consequences of potentially disastrous events.
- Organizations can better prioritize resources and take preparedness actions.
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What is hazard map?
A hazard map is a map that highlights areas that are affected by or are vulnerable to a particular hazard.
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How does hazard mapping play a role in long term planning?
- Maps the areas where earthquakes/hazardous events are most likely to occur.
- Enables planning of where important services and infrastructure should be located- land use zoning.
- Identifies correlation between risk and vulnerability.
74
What is land use zoning?
Ensuring that buildings with important services, such as hospitals, are not placed in areas at high risk of natural hazards.
75
How does Rebuilding Programmes play a role in long term planning?
- In order to minimise the impacts of collapsing buildings:
- Reducing the the number of buildings in high risk areas.
- Building earthquake resistant buildings.
- Existing buildings and structures, such as bridges can be retrofitted to make them safer in future events.
