Chapter 6 - Managing natural hazards Flashcards
(105 cards)
1
Q
What is a natural hazard?
A
A natural hazard is a naturally occurring event that will have a negative impact on people.
2
Q
What is a natural disaster?
A
A natural disaster is when a natural hazard causes damage and the people affected are unable to cope.
3
Q
Diagram of the earths inner structure
A
4
Q
Describe the characteristics of the inner core
A
Inner core has a temperature of 5000-6000 degrees Celsius, is solid due to the intense pressure from overlying rocks and is made from iron and nickel.
5
Q
Describe the characteristics of the outer core
A
Outer core has a temperature of 4000-5000oC, is liquid and is make from iron and nickel.
6
Q
Describe the characteristics of the mantle
A
Mantle has a temperature of 1000-1200oC, is liquid and flows slowly due to the convectional currents from the core and is made of mainly silicate minerals.
7
Q
Describe the characteristics of the oceanic crust
A
Oceanic crust is made from silicate and magnesium minerals, mainly made form basalt, thin at a depth of 6km, denser at 3g cm-3, younger and can sink and is continually being renewed and destroyed.
8
Q
Describe the characteristics of the continental crust
A
Continental crust is made from silicate and aluminium minerals, mainly made from granite, thick at a depth of 35km but can be up to 100km under mountain ranges, lighter as 2.6g cm-3, older and cannot sink and is neither destroyed nor renewed.
9
Q
What is a tectonic plate?
A
Tectonic plate is a piece of lithosphere that moves slowly. It is made of crust and upper mantle.
10
Q
What is the relation between convection currents and tectonic plates?
A
Where the convection currents rise to the surface, the plates move away from each other and where the convection currents sink, plates move towards each other.
11
Q
What is a plate boundary?
A
Plate boundary is where two or more plates meet, the three main types of plate boundaries are constructive, destructive and conservative.
12
Q
What are constructive (divergent) plate boundaries?
A
Constructive (divergent) plate boundaries are when two oceanic plates are pulling away from each other. A gap or weakness is formed and magma from the mantle rises to the surface due to convection currents. The magma solidifies when contact is made with the cold ocean water. The magma turns to lava and forms a new basaltic ocean crust. This process is called seafloor spreading or ridge push, this triggers a small earthquake. The new ocean crust builds up to form mid ocean ridges and can also form submarine volcanoes, which may grow an appear above sea level as volcanic islands. These volcanoes are called shield or basic volcanoes and usually have non-explosive eruptions because there is little pressure build up. An example of this type of plate boundary is where the Eurasian plate moves away from the north American plate along the mid-Atlantic ridge.
13
Q
What forms if continental plates move away from each other?
A
If two continental plates move away from each other, a rift valley may form as the central block of land drops down between the faults.
14
Q
What are destructive (convergent) plate boundaries?
A
Destructive (convergent) plate boundaries are when two plates move towards each other. This can occur between two oceanic plates, two continental plates or an oceanic plate and a continental plate. When an oceanic plate and continental plate move towards each other, the denser oceanic plate is forced down (subduction) under the lighter continental plate. This happens in the subduction zone and an ocean trench is formed. There trenches are the deepest parts of the ocean. The friction between the plate triggers earthquakes and the heat produced due to friction turns the descending plate into magma. The magma starts to rise and erupt due to pressure through a weakness in the crust as an explosive composite volcano. Fold mountains also formed. The magma that erupts at the surface forms a chain of volcanic islands called as island arc. If two continental plates move towards each other, the sediments between the two plates are compressed (collision zone) and pushed upwards to form fold mountains.
15
Q
What are fold mountains?
A
Fold mountains are mountains created where two or more tectonic plates are pushed together, compressing the rocks and folding them upwards.
16
Q
What are conservative plate boundaries?
A
Conservative plate boundaries occur when two plates slide past each other. They move at different speeds. The plates get locked together and pressure builds up until it is released as an earthquake.
17
Q
What is magnitude?
A
Magnitude measures the strength of an earthquake. It is measured om the Richter scale.
18
Q
What are volcanoes?
A
Volcanoes are caused due to tectonic activity. They are found on constructive and destructive plate boundaries.
19
Q
What is the focus of an earthquake?
A
Focus is where the earthquake begins underground.
20
Q
What is the epicentre of an earthquake?
A
Epicentre is the point on the surface above the focus.
21
Q
What is a seismometer?
A
Seismometer is an instrument used to measure the magnitude of an earthquake on the Richter scale.
22
Q
What are the nine factors affecting the impact of an earthquake?
A
location of the epicentre, time of the earthquake, geology of the area, relief of the area, severity of aftershocks, level of development of human settlement, population density, building density and building strength.
23
Q
What are the four conditions required for a tropical cyclone to form?
A
Tropical cyclones need to have ocean surface temperatures of at least 27oC, ocean depth of at least 60 meters, very little shear wind and these conditions must occur between 5o and 20o north or south of the equator to form.
24
Q
Why do tropical cyclones need warm oceans to form?
A
The warm ocean water provides the energy to evaporate more water that rises, and condenses, releasing huge amounts of energy.
25
Why do tropical cyclones only form between 5 and 20 degrees north or south of the equator?
The 5o and 20o north or south of the equator mean that there is an optimal amount of Coriolis force (rotation of the earth) to make the air spin fast enough.
26
why do tropical cyclones need little shear wind to form?
The little change in wind speed or direction prevents the stoppage of the vertical development.
27
When do tropical cyclones form and what direction do they spin?
They form between May and November in the northern hemisphere and spin clockwise. They form between November and May in the southern hemisphere and spin anticlockwise.
28
What is flooding?
Flooding is when the discharge of a river exceeds the capacity of the rivers channel. When this occurs, the river overflows the banks and covers the adjacent floodplain.
29
What are the eleven causes of flooding?
weather, previous weather, soil and rock type, relief, earthquakes/volcanoes/tropical cyclones, deforestation, urbanisation, agriculture and climate change
30
How does weather cause flooding?
heavy intense rainfall can exceed the infiltration capacity of the soil and lead to an increase in overland flow. Steady prolonged rainfall can saturate the soil and caused the water table to rise, reducing infiltration capacity. Overland flow will occur if snow melt is rapid and the ground beneath frozen.
31
How does previous weather cause flooding?
Antecedent soil moisture refers to the amount of water in the soil before a rainfall event. The more saturated the soil, the less infiltration and the more overland flow.
32
How does soil and rock type cause flooding?
Impermeable soils and rocks, such as clay or granite, have a low infiltration capacity and percolation rate, which leads to greater overland flow.
33
How does relief cause flooding?
Steeper gradients can lead to faster overland flow and water has little time to infiltrate.
34
How do earthquakes, volcanoes and tropical cyclones cause flooding?
These natural hazards can produce tsunamis and storm surges that flood low-lying coastal areas.
35
How does deforestation cause flooding?
Cutting down trees reduces interception and infiltration.
36
How does urbanisation cause flooding?
Concrete and tarmac are impermeable surfaces that lead to more overland flow. Store drains speed up the movement of water to the nearest river.
37
How does agriculture cause flooding?
Overgrazing and leaving soil expose reduces interception. Ploughing down rather than across lopes quickly channels the water downwards. Heavy farm machinery compacts the soil, making it impermeable.
38
How does climate change cause flooding?
Enhanced global warming may lead to a rise in sea levels, as well as more rainfall and storms in certain parts of the world.
39
What is drought?
Drought is when there is a lack of rain or less rain than normal over a long period of time.
40
How is drought caused and provide an example
Changes in atmospheric circulation patterns altering storm tracks and wind patterns. An example of this is patterns that prevent the northwards movement of the inter tropical convergence zone into the Sahel region of Africa, which means that the moist rising air at the inter tropical convergence zone does not move north to reach Sahel.
41
How can droughts occur?
Air in a high-pressure system sinks and rain clouds generally do not form. If the sinking air covers a large area than normal or becomes prolonged, droughts can occur
42
How does El Niño cause droughts?
The El Niño southern oscillation is a weather event where the surface water in the Pacific Ocean along south America rises in temperature. These warmer waters change circulation patters and alter storm patters and can cause droughts in Australia.
43
How does La Niña cause droughts?
La Niña is the counterpart to El Niño and is when the surface water in the Pacific Ocean along south America decreases in temperature. The cooler waters contribute to drier conditions in parts of north and south America.
44
How do warmer temperatures lead to drought?
Warmer temperatures worldwide from climate change leads to decreased rainfall and therefore leading to more drought events.
45
How do agricultural practices lead to drought?
Agricultural practices can make land more vulnerable to drought. Irrigation techniques have increased farmers dependence on water. Overcultivation and overgrazing can lead to soil compaction, and the soil is less able to hold water. As the soil becomes drier, it is vulnerable to erosion and eventually desertification.
46
How does deforestation lead to drought?
Deforestation as a lack of trees decreases soil infiltration and increases soil erosion.
47
How does the building of dams lead to droughts?
Building a dam on a large river can cause drought downstream of the dam by reducing the flow of water.
48
What are the twelve impacts of tectonic events?
damage to buildings and infrastructure, fires from ruptures of gas pipes, tsunamis hit coastlines, landslides cover buildings and roads, destruction of farmland leading to starvation, loss of wildlife habitats, water related diseases, contaminated water, loss of life, trauma, poor mental health and financial losses when repairing the damage.
49
What are the nine impacts of tropical cyclones?
flooding from storm surges and heavy rainfall, loss of life, damage to buildings and infrastructure, disruption of electricity, transport and water supply, water-borne diseases, economic loss as production is halted, damage to crops leading to food shortages and loss of export earnings, loss of wildlife habitats and financial losses when repairing the damage.
50
What are the nine impacts of flooding?
loss of life, damage to building and infrastructure, contamination of water supplies leading to disease, loss of livestock and crops leading to food shortages, water related diseases, deposition of silt from the flood waters, recharge of groundwater sources, rivers may change course and financial losses when repairing the damage.
51
What are the sixteen impacts of droughts?
death of organisms, water sources dry up, decline in crop yields, loss of crops, livestock, plants and wildlife, decrease in land prices as production declines and farmers lose money, migration from rural to urban areas, increase in food prices, starvation, increased soil erosion, health problems due to malnutrition, desertification, decrease in air quality, increased risk of wildfires and conflicts over water usage and food.
52
How can people predict earthquakes?
instruments such as seismometers can monitor tremors, groundwater levels and radon gas can also be measured, epicentres and the frequency of past events can be mapped to see if a pattern is developing, measurement of local magnetic fields, a hazard zone map can be drawn based on geological information and ground stability and unusual animal behaviour.
53
How can people prepare and protect themselves for earthquakes
earthquake proof or aseismic buildings, older buildings can be retrofitted, smart meters that cut off gas supplies and prevent fires and land use planning such as schools and hospitals are built in low-risk areas.
54
How can people predict volcanoes?
seismometers monitor tremors caused by rising magma, satellites using heat seeking cameras can measure increasing ground temperatures, tiltmeters and global positioning systems monitor changes in volcano shape and emissions of steam and sulphur dioxide can be monitored.
55
How can people prepare and protect themselves for volcanoes?
study past eruptions of a volcano and create a volcano hazard map, plans such as lava diversion channels, lava barriers, spraying lava with water and halting lava advance by dropping concrete slabs into the flow and building reinforcements for example sloping roots to protect against ashfall.
56
How can people predict tropical cyclones?
tropical cyclones are tracked using satellites.
57
How can people prepare and protect themselves for tropical cyclones?
cyclone shelters, buildings on stilts so not flooded by storm surges, embankments built along coasts and preserving mangrove swamps to absorb the energy of stromb surges.
58
How can people predict flooding?
monitoring the amount of rainfall change in the river discharge and knowledge about the characteristics of the drainage basin and type of storm is valuable for determining the possible severity of the flooding.
59
How can people prepare and protect themselves for flooding?
hard engineering projects which are physical structures that are permanent, often expensive and can impact on the environment such as leaves, flood barriers, flood control channels and dams, soft engineering products such as afforestation, controlled flooding of meadowland and storage basins, straightening, widening and deepening the river channel by dredging and clearing vegetation, land use planning to use higher land for settlements, restrict development on floodplains or increase greenspace, use of sandbags and pumps and adapt houses for position power socks to 1.5 meters above ground level.
60
How can people predict droughts?
monitoring precipitation and temperature.
61
How can people prepare and protect themselves for droughts?
increase water supplied by dams and reservoirs, percolation ponds, wells, pumps and use of aquifers, water transfer by pipeline and desalination, water conservation such as using storage tanks, spray irrigation, planting drought tolerant crops, reducing deforestation and increasing water recycling, agricultural improvements such as planting shelterbelts to reduce wind and evaporation, building low banks across a slope (bunds) to encourage infiltration and fencing to control overgrazing and government stockpiling supplies of water, food and medicine.
62
Why might some people stay but despite the risk of a natural hazard?
Individuals may have lived in an area all their life and want to be near family and friends. They do not perceive the risk to be very high, particularly if they have never experienced a natural hazard.
Confidence in prediction, preparation and protection methods.
Employment opportunities such as tourism as souvenir sellers and guides or in fishing.
An individual may have no choice in moving if there is pressure on land, or it is too expansive to move.
63
Why might people stay put near volcanoes despite the risk of a natural hazard?
In the case of volcanoes, fertile soils and created that product high crop yields. The scenery can be spectacular, geothermal power can supply a cheap form of power and there is the possibility of mining minerals such as sulphur, diamonds and gold.
64
Why people may stay put near flood prone areas despite the risk of a natural hazard?
In the case of flooding, rivers provide a source of food, water for drinking and irrigation, communications maybe easier and flat land either side of the river is available for building on.
65
Explain how tectonic plate movement causes magma to rise to the Earth's surface (4)
plates move apart / constructive boundary ;
plates pushed under another / destructive boundary / subduction ;
rock / plate melts / becomes magma ;
movements caused by convection currents ;
magma / molten rock behaves as a liquid ;
magma lighter than solid rock ;
(so magma rises) through vents ;
66
Earthquake A has a magnitude of 2 and earthquake B has a magnitude of 4. Explain how the magnitude of earthquake A compares to the magnitude of earthquake B (3)
B has a greater / higher / larger (magnitude than A) ;
B more risk / level of danger
100 x greater magnitude / each level is 10x increase in magnitude ;
67
Suggest why many farmers grow crops near volcanoes that can erupt (2)
limited land suitable for farming ;
soil is rich in minerals / do not need fertilisers / fertile soil ;
risk to life / crops is low ;
68
More economically developed countries (MEDCs) use strategies to manage the impact of
earthquakes before they happen. Explain these strategies (5)
land zoning / town planning regulations (to avoid construction in high risk areas) ;
buildings made to resist earthquakes ;
so less collapse / risk of killing people ;
disaster preparation / rapid response teams/medical aid/food and shelter ;
effective early warning systems / monitoring ;
so people know to evacuate ;
drills / preparation / plans ;
so evacuation is safe / controlled/prevents panic ;
people get to a safe area ;
69
Suggest two reasons why some typhoons do not reach land (2)
they change direction out at sea ;
they do not have enough energy to remain typhoons / reduce to storm force ;
predictions were incorrect ;
70
Suggest how an El Niño year affects the number of typhoons expected to reach Japan (2)
fewer typhoons ;
the sea not as hot (around / near Japan) / warmer water further away (from Japan) ;
so it is not hot enough to form a typhoon / only forms storms ;
typhoons move on a different track / typhoons move in an easterly direction ;
71
Describe how a tsunami occurs (3)
tectonic event / volcano; / earthquake / plate movement;
causes sudden movement in ocean;
creates large waves (reach land) / wave get larger as reaches shallow water / shore;
72
Suggest the type of plate boundary that the Tungurahua volcano is found on (1)
destructive ;
73
Suggest the benefits and limitations of monitoring the volcano as a strategy for managing the impacts of a future eruption (3)
benefits
volunteers are local so committed to monitoring ;
educates the community about the risks ;
community given early warning of eruption ;
people trust volunteers as they are local ;
limitations
data may not be, reliable / valid / scientific ;
requires lots of volunteers ;
requires volunteers to be trained ;
could be dangerous ;
74
Explain two reasons why people choose to live close to a volcano (4)
fertile soils ; increased crop production ;
extraction of minerals ; can be sold for profit ;
geothermal energy resource ; used to, heat homes / provide electricity ;
volcano brings in tourists ; job opportunities / income ;
traditional home ; can’t afford to move/ so not want to move / tied to local employment ;
suitable land for a town ; flat land ;
trust on the monitoring systems ; perceived to be low risk ;
75
State two strategies for managing the impacts of drought (2)
monitoring ;
emergency water supplies ;
water conservation ;
increased water supply or stated example: dams / reservoirs / wells / aquifers, water transfer / desalination / rainwater
harvesting ;
international aid ;
grow drought resistant crops ;
76
Suggest reasons why this sign is used in areas at risk from tsunamis (3)
people are warned / made aware (of the risk)/educated (on risk);
to avoid, loss of life / injury / (risk of) drowning;
people know / advised that there is a (evacuation) shelter / building / where the shelter is / for faster evacuation;
people advised to get to high ground;
people may not be able to read;
77
Describe the impact caused by Cyclone Tauktae over the period shown on the map (3)
heavy rainfall / flooding ;
storm surges;
high winds ;
damage qualified e.g. powerlines down / buildings destroyed / bridges swept away / loss of crops;
water contamination;
loss of life / injury;
habitat loss;
78
Describe the strategies that can be used to manage the impact of tropical cyclones (4)
monitoring / warning;
disaster preparation (plans, drills, emergency supplies and emergency rescue teams);
evacuation;
emergency shelters;
rebuilding of damaged areas / structure of buildings;
international aid;
better flood defences;
79
Describe the effects of drought on the area shown in the photograph (2)
no plants / vegetation;
reduced water (in river/lake);
cracks in land;
dry soil / desertification;
80
State three impacts of drought on local people (3)
reduced water, source / availability;
decline in crop yield;
starvation / famine;
(forced) migration;
lack of employment / income;
respiratory problems caused by, dust / decrease in air quality;
danger from increased risk of wildfires;
81
State three ways to prepare for a natural hazard to help prevent deaths (3)
evacuation plans;
drills;
emergency supplies;
emergency rescue teams;
early warning systems / monitoring;
education of public;
emergency shelters;
medical teams;
earthquake resistant buildings;
82
State three causes of flooding (3)
heavy rainfall;
low-lying land;
saturated / compacted, soil;
deforestation / removal of vegetation;
urbanisation;
storm surges / tsunamis;
83
State three impacts of a tropical cyclone on a coastal city (3)
flooding;
loss of life / injuries;
loss of livestock / crops;
financial losses / jobs;
damage to, buildings / infrastructure;
contamination of water supplies / water-related diseases;
food shortages / starvation;
84
State the causes of drought (2)
lack of rain;
(prolonged) high pressure;
effect of, El Nino Southern Oscillation / La Nina, (on ocean temperatures and evaporation);
effect of climate change;
deforestation;
change in the water cycle;
85
The student concludes that the article does not prove the climate crisis is getting worse. Suggest why (3)
data only given for, one year / 2019;
lack of historic data to compare;
data does not indicate whether the figures are an increase / single year doesn’t show a trend;
some natural disasters are not caused by climate change;
AVP, e.g. loss of homes might (also) be due to other reasons rather than natural disasters, article not (necessarily) written
by scientists;
86
Explain how droughts can cause soil erosion (2)
(lack of rain causes) plant death;
reduced number of roots to hold soil;
lack of vegetation to slow wind speed;
lighter soil blown by wind;
bare soil easily washed away when rain eventually falls;
87
Suggest how the loss of homes can increase the number of deaths due to a natural disaster (3)
overcrowded / unplanned, emergency accommodation;
lack of clean water;
lack of sanitation;
poor diet;
less access to medical facilities;
lack of shelter / exposure to weather;
88
Suggest how climate change may affect the number and distribution of tropical cyclones (3)
number increases;
wider distribution (further away from the tropics);
(more areas have) high enough water temperatures;
increase in sea levels results in more areas with deep water;
89
Explain how tropical cyclones increase the chance of water-related diseases (3)
damage to infrastructure / flooding;
sewage / dead animals / named pollutant;
lack of clean drinking water/ have to drink contaminated water;
sewage contains bacteria / cholera;
standing/stagnant water;
increase in breeding site mosquitoes;
increase in vectors / ref to malaria;
90
State two impacts that tropical cyclones have on people (2)
increased water related diseases;
flooding;
loss of life;
financial losses / loss of jobs;
damage to buildings and infrastructure;
loss of, crops / animals;
malnutrition / famine;
91
Describe the cause of an earthquake (3)
movement / slide / converge / divergence of (tectonic) plates;
due to convection currents;
friction at plate boundary;
build-up of pressure;
pressure overcomes friction;
release of energy / (seismic) waves;
move outward (from focus / epicentre);
92
Describe three ways that the design of the building reduces the impacts of an earthquake (3)
hollow concrete building blocks, are lighter / cause less damage if they fall;
strong roof, is less likely to collapse / allows for air spaces / protects from falling debris;
low height, is less risk from falling / more compact;
small windows reduce risk of broken glass / fewer weak spots in walls;
steel pillars into solid rock provide secure / strong foundation;
93
Some earthquakes with a large magnitude do not cause any deaths or injuries. One reason for this could be earthquake-resistant buildings. Suggest other reasons (3)
monitoring / early warning systems in place;
disaster preparation / evacuation plans in place;
epicentre might be in a geographically remote / unpopulated location; land use zoning;
deeper earthquakes can be less damaging;
94
Suggest why people continue to live in places which are at high risk of earthquakes (3)
traditional / family reasons;
employment / livelihood;
lots of natural resources in area;
too costly to live elsewhere / lack of alternatives;
perceive the risk is small / confident of measures in place;
95
Suggest how the work being done in the photograph reduces the risk of flooding (2)
increases the depth (of the river);
increases the width (of the river);
96
Describe four other methods to reduce the impacts of flooding in the area (4)
increase / construct flood defences;
early warning systems;
land zoning / do not build on flood plains;
construction of relief drains;
emergency drills / relief shelters;
straightening of water courses;
97
State three impacts of a tropical cyclone (3)
flooding;
loss of life / injury;
financial losses / loss of jobs / employment;
damage to buildings / infrastructure;
loss of crops / livestock;
loss of habitats;
water-related disease / unsafe water / contaminated water;
98
Describe strategies for managing the impacts of a tropical cyclone (3)
monitoring / early warning to allow for;
evacuation plans;
(preparation of emergency) shelters;
stockpiling of supplies / food / water / electricity generators;
(preparation of) rescue teams;
(preparation of) medical teams / supplies / support;
design of buildings / infrastructure, to withstand high winds / floods / storm surges;
establishing communications;
involvement of international aid agencies;
99
Suggest strategies to reduce the impacts of the flooding at this location (3)
flood defences / higher banks / walls;
raise height of bridge;
build houses on stilts;
land zoning;
monitoring and warning systems;
rescue and flood management techniques / emergency rescue teams;
disaster preparation (plans, drills, emergency supplies);
international aid;
100
Suggest why climate change may increase the impacts of tropical cyclones (4)
warmer, seas / oceans:
increases areas where cyclones can form;
increases, frequency of cyclones;
longer cyclone season;
higher sea levels (mean bigger, storm surges / waves);
stronger wind speeds / more extreme cyclones;
increased rainfall;
current defences not designed for stronger storms;
low lying coastal communities have high population density;
more people living in high-risk areas;
101
Describe what causes a volcano to erupt (3)
(tectonic) plates move / at plate boundaries;
pressure of magma;
Earth’s crust is thin;
magma rises ;
comes out / breaks through the, crust / cracks / vents;
(as) molten lava / ash ;
102
Suggest reasons why each island in the Canary Islands is smaller than when it first formed millions of years ago (2)
erosion;
erosion by (sea) water / wind;
sea level rise;
103
State the meaning of tsunami (1)
a large wave;
104
Describe the possible impacts of a landslide and tsunami on the island of La Palma (3)
flooding;
death / injury;
from drowning / rocks falling;
evacuation;
damage to buildings;
damage to agriculture, e.g. crops, farmland, livestock;
damage to infrastructure, e.g. communications, transport networks;
loss of jobs / damage to the economy ;
AVP’s;; e.g. cholera / typhoid / water borne disease OR loss of biodiversity
105
State three strategies for managing the impacts of a tsunami (3)
monitoring stations;
warning systems;
evacuation (plan);
(evacuation) drills;
(emergency) rescue teams;
(emergency) shelters;
stores of food and water;
medical aid ;
AVP e.g. build seawalls / only build on high ground
