Hazards

Question 1

What is a hazard?

Answer 1

A potential danger that threatens the life of human-beings and their property.

Question 2

What is a natural event?

Answer 2

Something that occurs without the provocation of man or other living beings (in the physical environment)
Eg. A volcanic eruption.

Question 3

What is a disaster?

Answer 3

A big problem that can change the world, a country, or live for some.

Question 4

What is a natural disaster?

Answer 4

A natural event or hazard causing damage and destruction to property, as well as causing personal injuries or death: the realisation of a hazard. An event only becomes a disaster when the outcome is catastrophic.

Question 5

What are man-made hazards?

Answer 5

They are created by people or as a byproduct of their actions (direct or indirect, intentional or unintentional).

Question 6

What is the distribution of tectonic hazards?

Answer 6

They tend to be located on the plate boundaries of the tectonic plates making up the Earth’s crust. Also around the Pacific ring of Fire, on the East coast of Asia and West coasts of North and South America, which is an area of high tectonic activity. Often volcanoes are paired with earthquakes, with one provoking the other.

Question 7

What is the structure of the Earth?

Answer 7

Inner core, outer core, mantle, earths crust.

Question 8

Why do the tectonic plates move around the crust? (Talk about convection currents).

Answer 8

Convection currents under the earths crust cause the asthenosphere to rise. The hot particles are less dense and therefore move upwards and outwards (or inwards), pushing the plates apart (or pulling them together). Then, as the particles cool down, they become more dense and descend, then heat up again, causing the cycle to recommence.

Question 9

What happens at the destructive plate margin?

Answer 9

The oceanic crust is forced down by the continental crust.
The rubbing and friction between the two plates causes an earthquake.
The oceanic crust melts and becomes a part of the mantle, however some magma is forced to the surface, creating a volcanic eruption. The oceanic crust is destroyed.
Eg. The western coast of North America.

Question 10

What happens at the constructive plate margin?

Answer 10

Two oceanic crusts separate, forcing magma from the mantle upwards to the surface (a volcanic eruption).
As the magma cools and solidifies, it forms a new crust, and may also form a volcanic island.
Earthquakes and volcanoes (relatively gentle).
Eg. Mid-Atlantic ridge and Iceland, Haimaiey (Iceland).

Question 11

What happens at the conservative plate margin?

Answer 11

Plates move past each other forming violent, jerky earthquakes.
No crust is created or destroyed.
Can be two oceanic, two continental, or one oceanic and one continental.
Eg. San Andreas, California, USA

Question 12

What happens at the collision plate boundary?

Answer 12

Two continental plates crash together to form mountains.
Crust crumbles and is forced up to form these mountains.
Eg. Mt Everest

Question 13

Why do people live in tectonic hazard areas?

Volcanoes

Answer 13

Fertile soils:
Ash and lava decompose and produce mineral-rich soils, perfect for planting crops Eg. Mt Etna, Italy.
Scenic value:
In beautiful areas, high mountains with brilliant numbers of flora and fauna and biodiversity.
Tourism:
Skiing etc Eg. Yellowstone national park.
Cheap geothermal energy and hot water:
Eg. Iceland.

Question 14

Why do people live in tectonic hazard areas? (Earthquakes)

Answer 14

Some scenic value.
Tourism: mountains are formed.
People don’t know about them, and when they will occur Eg. Italy
Safe and secure building designs:
Reassure the population Eg. Japan, San Francisco.

Question 15

Why do people live in tectonic hazard areas? (Both volcanoes and earthquakes)

Answer 15

Mineral wealth:
Diamonds and other minerals occur at plate margins Eg. The Philippines.
Scientific interest:
Scientists want to understand more about how, why and when tectonic hazards occur. Also for the nature and engineering etc.
More jobs:
Search and Rescue, engineering, scientists etc.
Family:
Families have been living there for generations, and don’t want to move to keep the tradition.
People can’t move:
They are too poor or unwell to do so.
The benefits outweigh the risks.

Question 16

What are the economic impacts of volcanoes?

Answer 16

Destroys livelihoods.
Crops fail due to toxic lahar.
Tourists are afraid to come for a while, so less tourism.
Routes and roads to access the area are blocked (less tourism).
Scientists are interested so decide to travel to the country to analyse the disaster.
Increase in funerals: increase in wealth for the funeral industry.
Livestock die/run away: decrease in wealth in agriculture industry.
Hospitals full.

Question 17

What are the environmental impacts of volcanoes?

Answer 17

Eruptions destroy habitats.
Pyroclastic flows burn and intoxicate the habitats, may kill animals and plants too (both common and rare species).
Ash and lava create fertile soil, so more crops can grow more healthily, and forests can flourish.
Unbalanced ecosystems and food webs.

Question 18

What are the social impacts of volcanoes?

Answer 18

Traffic: tourists want to go home, and locals might want/need to evacuate.
Many deaths: grief.
Schools, homes and hospitals destroyed.
People need to be evacuated from the area.
Traditional family livelihoods destroyed.

Question 19

Volcano case study.

Answer 19

Mount Ontake, Japan.

Question 20

How do earthquakes occur?

Answer 20

Plates start to move (convection currents).
Two plates move against each other with jagged edges causing a jerky movement. Increase in friction.
Plates get stuck, and can’t move past each other, causing a build-up in pressure due to the friction between the plates.
The pressure is suddenly released when it becomes too great, leading to a sudden, jerky movement and vibrations: an earthquake is felt on the surface.

Question 21

Where do earthquakes occur?

Answer 21

At all four plate margins.
Very rarely, they can occur in the middle of plates on old faultlines or due to human activity (fracking, mining, the building of dams and reservoirs).
Distribution and patterns not random.
2/3 of all large earthquakes have been around the Pacific ring of Fire.
Along the mid-Atlantic ridge.
Across Southern Europe and Asia, linking the Atlantic and Pacific oceans.

Question 22

What are the economic effects of earthquakes?

Answer 22

Livestock run away/are harmed.
Crops are damaged.
Increase in demand for funerals.
Increase in demand for medical attention.
Country/ies affected need to spend more money on safe buildings, businesses, doctors, hospitals etc.
Tourism in the area decreases in popularity.

Question 23

What are the environmental effects of earthquakes?

Answer 23

Buildings collapsing.
Animals can be harmed.
Plants can be harmed.
Roads and infrastructure destroyed by collapsing trees and buildings.
Avalanches.
Land slides.
Tsunamis.
Accessibility of area in reduced, which can greatly affect how rescue teams can enter to help.
Zonation of areas to keep dangerous areas out-of-bounds.
Trees falling.
Water pipes, gas mains and electric wires fracture, which can cause explosions or water contamination (as sewage pipes can fracture too).

Question 24

What are the social effects of earthquakes?

Answer 24

People are afraid.
People are psychologically scarred.
There are numerous deaths, which leads to grief.
Diseases (due to contaminated water etc) spread.
Homes are destroyed.
People may need to me evacuated.
Homelessness.
High concentrations of people in small areas: disease can spread faster.
Increase in looting.
Schools and hospitals closed.
Injury.
Increase in funerals.

Question 25

What are primary effects?

Answer 25

Effects of events which occur as a direct result of that event.

Question 26

What are secondary effects?

Answer 26

Effects of events which occur as a result of a primary effect.

Question 27

Why are some earthquakes worse that others?

Answer 27

Impact can be affected by:
Where the earthquake occurs within the crust (the focus): the more shallow the focus, the more it will be felt on the surface. The deeper the focus, the more the shock waves will be dissipated and less felt on the surface.
Whether the earthquake occurs in an urban or rural area.
Whether the country is well developed or not.
The type of shock-wave (P waves or S waves).

Question 28

How can we predict earthquakes?

Answer 28

Prediction decreases vulnerability.
Prediction of an earthquake is extremely difficult.
History shows that large earthquakes tend to have 50-100 year cycles.
Constant observation by scientists using specialised equipment used to detect seismic activity in MEDCs.
Small tremors or earthquakes (foreshocks) occur prior to large earthquakes.
Unusual animal behaviour.

Question 29

How can we protect ourselves against earthquakes?

Answer 29

Drills (when there is no time/it is too dangerous to evacuate: drop (onto the floor), cover (your head), hold on (to a stable object).
Knowledge about earthquakes, and what might happen.
Search and Rescue teams on the ready.
Safe, specially engineered buildings adapted to withstand earthquakes.

Question 30

How are some buildings adapted to withstand earthquakes?

Answer 30

Cross-bracing (flexibility). Eg. Birds nest stadium, Beijing.
Pyramidal structure offers stability. Eg. TransAmerica Pyramid, San Francisco.
Dome shape. Eg. The Egg, Beijing.
Deep foundations.
Rolling effects on foundations (flexibility, counter-acts movement).
Shock absorbers.
Weights on roof.
Inter-locking (increases strength).
Built on open-spaces (nothing to fall onto, space to evacuate).
Built on water (absorbs shocks).
Hollow bricks.
Stone foundations.

Question 31

Earthquake case study.

Answer 31

Italy earthquake.

Question 32

What are tropical storms?

Answer 32

Intense low-pressure systems that bring with them torrential rain and winds of over 160km/h (can reach 250km/h).

Question 33

What are the ingredients for a tropical storm?

Answer 33

Heat.
Hot water 27°C.
Mid-late summer.
5°-20° north and south of the equator.
Very fast, rising hot air.

Question 34

What are the characteristics of a tropical storm?

Answer 34

Very heavy rainfall-flooding-rivers break their banks-saturated land.
High winds often 160km/h to 250km/h-very big waves-storm surges-flooding of coastal areas.
Heavy rain-saturated land-unstable slopes-landslides and mudslides.
Intense low pressure.
Thunderstorms and lightning.
Dirty wind (contains debris-kills people).
High pressure in the air.
Low pressure on the ground, gets lower as you approach the eye.

Question 35

What are the economic impacts of tropical storms?

Answer 35

Houses washed away very rapidly.
Huge amounts of money lost by damage.
Crops covered in mud-crop failure.
Live stock run away/die.
Lost livelihoods.
Electricity out.
Houses, infrastructure destroyed-costs q lot of money to rebuild.

Question 36

What are the environmental impacts of tropical storms?

Answer 36

Rivers change course and speed.
Erosion occurs at a very rapid rate.
Flooding (breaking of river banks).
Rotting of trapped livestock: disease.
Destruction of habitats.
Infrastructure destroyed.
Animals run away/die.
Plants die.
Water source contaminated: disease.

Question 37

What are the social impacts of tropical storms?

Answer 37

Stranded families.
Evacuation from homes.
Homes washed away.
Death of loved ones.
Psychologically scarred.
Electricity out.
Infrastructure destroyed so people can't escape/visit: hard for rescue teams to help, hard to access.

Question 39

Tropical storm case study.

Answer 39

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Question 40

How can LEDCs protect themselves from hazards?

Answer 40

Charities.
Animals in pens (prevents them from running away).
Help from other governments and countries.

Question 41

How can we predict and protect against tropical storms?

Answer 41

Use extensive sea walls. They act as a barrier to coastal flooding from storm surges, and they reduce energy and waves, reducing erosion.
Track the storm using satellite imagery, and warn you about others.
Flood-proofing buildings by using shutters on the windows and shatter-proof glass, for example.
Putting houses on stilts to withstand strong winds and floods, and allowing water to pass under the houses.
Emergency rescue teams are always on the ready.
Air radar and remote sensing sonds.
Strong materials used to make buildings: easier to withstand winds and floods.
Using good, regular communications.
Using land radar.
Storm warden patrols.
Clear evacuation routes.
Extensive medical and paramedic provision.
Eg. In Texas, USA.