the challenge of natural hazards

Question 1

What is a natural hazard?

Answer 1

A natural hazard is a natural process which could cause disruption to people and property.

Question 2

What is a natural disaster?

Answer 2

A natural disaster is a natural hazard that has already happened.

Question 3

What is an extreme event?

Answer 3

An extreme event doesn’t pose any threat to human activity.

Question 4

What are the two types of natural hazard and how are they categorised?

Answer 4

types of natural hazard:

1) geological - caused by land and tectonic processes
2) meteorological - caused by weather and climate

Question 5

What is hazard risk?

Answer 5

Hazard risk is the probability of a natural hazard happening.

Question 6

Name three factors affecting hazard risk.

Answer 6

factors affecting hazard risk:

• vulnerability
• capacity to cope
• nature of natural hazards (predictability, frequency, magnitude)

Question 7

What is the difference between continental and oceanic crust?

Answer 7

Continental crust is 30-50 km and is less dense.

Oceanic crust is 5-10 km and is denser.

Question 8

Describe what happens at both types of destructive plate margin.

Answer 8

destructive plate margin:
1) one continental and one oceanic move towards each other, the denser oceanic crust submerges below the continental and is destroyed

2) two continental move towards each other, ground is folded and forced upwards

Question 9

Describe what happens at a constructive plate margin.

Answer 9

constructive plate margin:

- two plates move away from each other, magma rises and cools to form crust

Question 10

Describe what happens at a conservative plate margin.

Answer 10

conservative plate margin:
- two plates move sideways past each other, crust isn’t created or destroyed but release of pressure can cause an earthquake

Question 11

Give an example of a destructive plate margin.

Answer 11

An example of a destructive plate margin is the west coast of South America.

Question 12

Give an example of a constructive plate margin.

Answer 12

An example of a constructive plate margin is the mid-Atlantic ridge.

Question 13

Give an example of a conservative plate margin.

Answer 13

An example of a conservative plate margin is the west coast of the USA.

Question 14

Where can volcanoes occur?

Answer 14

where volcanoes occur:

• destructive, pool of magma when oceanic plate melts, rises through cracks and erupts
• constructive, magma rises in gap
• at hot spots over the mantle (eg. Hawaii)

Question 15

What is erupted from a volcano?

Answer 15

When a volcano erupts, it emits lava, gases, ash and pyroclastic flows (heated currents of gas, ash and rock).

Question 16

Where can earthquakes occur?

Answer 16

where earthquakes occur:

• destructive, tension builds when one gets stuck
• constructive, tension builds along cracks within plates
• conservative, tension builds when grinding

Question 17

What is the focus of an earthquake?

Answer 17

The focus of an earthquake is where energy is released within the crust.

Question 18

What is the epicentre of an earthquake?

Answer 18

The epicentre of an earthquake is the point on the surface directly above the focus.

Question 19

What is the fault of an earthquake?

Answer 19

The fault of an earthquake is where the tension builds.

Question 20

What are the seismic waves of an earthquake? What is the difference between P and S waves?

Answer 20

The seismic waves of an earthquake are the energy that move through the crust and surface. P waves move up and down and S waves moves side to side.

Question 21

What does the magnitude scale show? What does each unit mean?

Answer 21

The magnitude scale measures how much energy is released in an earthquake. Each unit represents a 10x more powerful earthquake. 1-6 means slight damage. 7+ means major damage.

Question 22

Give six reasons why people live in areas at risk.

Answer 22

living in areas at risk:

• they have always lived there
• employed there
• government is good
• think earthquakes and volcanoes won’t happen
• soil from volcanoes is fertile
• volcanoes are tourist attractions

Question 23

What are the four ways of managing to reduce the effects of natural hazards?

Answer 23

management:

• monitoring - seisometers and lasers moniter earth
• prediction - earthquakes can’t be reliably predicted, but monitor plate movements, volcanoes can be predicted
• protection - buildings designed to withstand earthquakes (eg. concrete), strengthen
• planning - future developments, emergency services, education, plan evacuation routes, emergency supplies stock piled

Question 24

Describe the global atmospheric circulation.

Answer 24

At the equator, hot air rises leading to low pressure and rainfall. When the air reaches the edge of the atmosphere, it cannot travel any further and so goes north or south. The air becomes cold and falls to create dry, cloudless areas at about 30 degrees. This continues at every 30 degrees.

Question 25

In what conditions do tropical storms form?

Answer 25

Tropical storms form at 27+ degrees Celsius and when the difference in wind speed is low. Typically between 5 and 30 degrees N/S in late summer or autumn as this is the warmest water.

Question 26

Describe the formation of tropical storms.

Answer 26

formation of tropical storms:

1) warm, moist air rises, leading to condensation
2) this releases energy and an area of low pressure
3) combined with surface winds, it rises up in a spiral due to the Earth’s rotation
- the condensed clouds are cumulonimbus clouds
- the centre of the storm is where cold air sinks.

Question 27

What are the two different pressure systems that bring different types of weather into the UK?

Answer 27

pressure systems:

• depressions - an area of low atmospheric pressure, move east along the UK, air rises forming clouds
• anticyclones - areas of high pressure formed when cool air sinks, spin anticlockwise, in summer bring hot, in winter bring fog and frost

Question 28

What eight types of weather affect the UK?

Answer 28

UK weather hazards:

• rain
• snow and ice
• hailstorms
• drought
• wind - strongest in coastal areas
• thunderstorms - most common in south and east during summer
• heat waves

Question 29

What is the evidence that weather in the UK is becoming more extreme? (for temperature and rain)

Answer 29

more extreme UK weather:

• temperature - Dec 2010 was coldest in over 100 years, but April 2011 was warmest April on record
• rain - 2013 was wettest year on record, Dec 2015 was wettest month ever recorded

Question 30

What is the pattern of the quarternary period and how is this evidence for climate change?

Answer 30

evidence for climate change:

• the Quaternary period is about 2.6 million years ago to now
• during this period, the global temperature falls for 100,000 years and warm periods last 10,000 years
• the last cold period ended 15,000 years ago so we are due an ice age

Question 31

What is four sources of evidence for climate change?

Answer 31

evidence for climate change:

1) ice and sediment cores
- one layer of ice is formed each year, so scientists drill into ice and analyse gases trapped in the ice to tell what temperature it is each year

2) temperature records
- since the 1850’s
- gives am accurate short term record of temperature change

3) pollen analysis
- pollen from planets gets preserved in sediment and scientists can identify and date the pollen to show which species were living at that time
- they know what conditions these species live in and so can identify the conditions at the time

4) tree rings
- trees grow new rings every year and these rings are thicker in warm, wet conditions
- this gives reliable evidence for the past 10,000 years

Question 32

What are the three natural causes of climate change?

Answer 32

natural causes of climate change:
natural causes of climate change:
1) orbital changes
- the way the Earth moves around the Sun changes, which affects the amount of solar radiation the Earth receives

2) volcanic activity
- major eruptions eruptions eject large quantities of material into the atmosphere
- some reflect the Sun’s rays back into space, so the Earth cools
- they release carbon dioxide

3) solar output
- the Sun’s output of energy isn’t constant
- there is cycles of about 11 years
- scientists say this doesn’t have a major impact

Question 33

What are the four human causes of climate change?

Answer 33

human causes of climate change:

1) burning fossil fuels
- coal, oil, gas and petrol

2) farming
- methane from livestock
- flooded fields emit methane

3) cement production
- made from limestone, which contains carbon and burning it releases carbon dioxide

4) deforestation
- plants remove carbon dioxide from the atmosphere
- when they are chopped down, they stop taking in carbon dioxide
- when they are burnt, they release carbon dioxide

Question 34

What are the environmental effects of climate change?

Answer 34

environmental effects of climate change:

• glaciers shrink and ice sheets melt, which means water is stored on land and sea levels will rise, leading to flooding and increased coastal erosion
• sea ice is shrinking, leading to loss of habitat
• precipitation patterns are changing
• biodiversity is decreasing as species are less adapted

Question 35

What are the social effects of climate change?

Answer 35

social effects of climate change:

• deaths due to heat increased
• some areas become difficult or impossible to inhabit
• struggle to supply water
• affecting crops, both positively and negatively
• more money spent on predicting events and reducing impacts

Question 36

How does mitigation strategies reduce the causes of climate change?

Answer 36

mitigation strategies:
- carbon capture - CCS (carbon capture and storage) reduces emissions by transporting and storing it safely underground

• international agreements - from 1997, most countries agreed to monitor greenhouse gas emissions by signing an international agreement called Kyoto Protocol. the EU is 20% lower from 1990 to 2020
• planting trees - absorbs carbon dioxide
• alternative energy production - replacing fossil fuels with renewable energy

Question 37

How does adaption strategies respond to climate change?

Answer 37

adaption strategies:
- changing agricultural systems - plant new crop types more suitable to climate and biotechnology to create new crop varieties

• managing water supply - water meters installed in homes to discourage using lots of water, collect and recycle rainwater
• coping with rising sea levels - physical defenses like flood barriers, better flood warning systems and build houses on earth embankments or on stilts