Section A: The challenge of natural hazards

Question 1

Define natural hazard

Answer 1

A natural event/process that threatens people or has the potential to cause injury, damage, destruction and death

Question 2

Two types of natural hazard

Answer 2

Atmospheric/Meteorological- created in atmosphere by weather and climate, movement of air and water.
Geological- created by the movement of the earth’s tectonic plates or surface rock/soils (land and tectonic processes).

Question 3

Give 3 examples of atmospheric/meteorological hazards

Answer 3

Extreme weather (heatwave/cold spells)
Tropical storm
Wind
Climate change

Question 4

Give 3 examples of geological hazards

Answer 4

Volcanoes
Earthquakes
Landslides

Question 5

2 factors affecting hazard risk (vulnerability)

Answer 5

Population density and distribution

Question 6

2 factors affecting hazard risk (capacity to cope)

Answer 6

Level of development of the place (££ to predict, prepare and prevent)
HIC’s better at coping (stable government, technology, planning laws in vulnerable places, agencies to respond)

Question 7

3 factors affecting hazard risk (nature of natural hazard)

Answer 7

Type of natural hazard (tropical storms predicted and monitored, time to evacuate/ earthquakes sudden and harder to protect)
Frequency (more often increase risk)
Magnitude (more severe cause greater effects)

Question 8

What is the plate tectonics theory

Answer 8

a theory that tries to explain how the earth is structured, and what it is made up of (inside earth, many different layers)

Question 9

Global distribution of earthquakes

Answer 9

Found along all types of plate margins
In narrow belts around the world.
Around the Pacific ring of Fire.
Along the west coast of North and South America.
Along the east coast of Asia
Occasionally found in middle of plates called ‘hot spots’ (hawaii)

Question 10

Global distribution of volcanoes

Answer 10

Only occur at constructive (Iceland the along the Mid-Atlantic Ridge) and destructive (Cascade Range in the Pacific Northwest) plate margins
“hot spots” in the middle of plates (Hawaii)
Pacific plate, which underlies most of the Pacific Ocean- ring of fire, where the majority of the world’s volcanoes occur, is around the edges of the Pacific Plate
From top on Nazca plate down south west along South american plate
South west of north american plate down to west of pacific plate along japan

Question 11

Destructive plate margin

Answer 11

Oceanic and continental plate move towards each other
Denser oceanic plate subducts beneath less dense continental plate
As sinks, it melts and makes magma called andesite
The sinking oceanic plate can stick to the continental plate, pressure builds up against friction causing earthquakes

Question 12

Constructive plate margin

Answer 12

Two oceanic plates move apart from each other
New oceanic crust is forming constantly in gap created
The magma is injected between the two plates- as it cools it forms new oceanic crust
The magma is runny- shallow sided volcanoes form
Earthquakes are caused by friction as the plates tear apart

Question 13

Conservative plate margin

Answer 13

As plates slide past each other, friction between them causes earthquakes
Plates can be moving in different directions or the same direction at different speeds
No volcanoes

Question 14

Give example of LIC tectonic hazard

Answer 14

Nepal earthquake
25th April 2015
7.9 Richter scale
Indo-Australian plate colliding with Eurasian plate at 45mm per year

Question 15

Give 4 primary effects of LIC tectonic hazard

Answer 15

8841 dead and 16800 injured
1mil homeless
Historic buildings and temples destroyed (Dharahara tower, UNESCO WH site) and 200 people trapped- no compulsory building standards
26 hospitals and 50% of schools destroyed
Reduced food, water and electricity storage

Question 16

Give 3 secondary effects of LIC tectonic hazard

Answer 16

Triggered avalanche on Mount Everest: 19 died inc. tourists and Nepal Sherpas (ethnic group working in tourist industry so death lost income that lift out of poverty)
Tourism was 8.9% of Nepal’s GDP, 1.1mil jobs: expected increase of 5.8% in 2015 shrunk recovering from earthquake- loss of jobs and -ve effect on economy
Rich seed storage in homes ruined by rubble caused food shortages and income loss (occured pre monsoon season when rice planted, staple diet and 2/3 of population depends on this farming)

Question 17

Give 4 immediate responses of LIC tectonic hazard

Answer 17

DEC raised $126mil to provide emergency aid and start rebuilding in worst hit areas
Temporary shelters set up (Red Cross provided tents for 225,000)
UN and WHealth Org distributed medical supplies to worst affected districts
Facebook launched safety feature so people could identify themselves as safe

Question 18

Give 3 long term responses of LIC tectonic hazard

Answer 18

Nepal government (and UN, EU, Wbank) carried out post disaster needs assessment
23 areas required rebuilding and eight months after the OCHA reported that $274mil of aid committed to recovery efforts
6 month recovery phase by food and agriculture org. of UN: crop production and growing seasons, individuals trained how to maintain and repair irrigation channels that damaged by landslides in earthquake

Question 19

Give example of HIC tectonic hazard

Answer 19

L’Aquila Italy earthquake
6th April 2009
6.3 on Richter scale
Eurasian and African plates pulled apart

Question 20

Give 4 primary effects of HIC tectonic hazard

Answer 20

308 killed and 1500 injured
67,000 homeless
10-15K buildings collapsed including: churches and medieval buildings and monuments with considerable cultural value, Basilica of Bernardino and national museum
San Salvatore hospital severely damaged: patients evacuated as could not cope with injured victims
Buildings in L’Aquila University destroyed inc. fatalities in it’s student accommodation

Question 21

Give 4 secondary effects of HIC tectonic hazard

Answer 21

Aftershocks triggered landslides and rockfalls causing damage to housing and transport (one caused by burst pipeline near town of Paganio)
Number of students at L’Aquila University decreased
Lack of housing for residents mean house prices increase
Much of city’s CBD cut off due to unsafe buildings- ‘red zones’ still exist reducing business, tourism and income

Question 22

Give 4 immediate responses of HIC tectonic hazard

Answer 22

Shelter provided for 10k people and 40k tents given out
PM Silvio Berlusconi offered shelters including some of his homes and train carriages
Red Cross searched for survivors- helped by 7 dog units and 36 ambulances
Water, hot meals, tents and blankets distributed and Red Cross raised £171,000 in support

Question 23

Give 4 long term responses of HIC tectonic hazard

Answer 23

Torch lit procession took place with Catholic mass on anniversary of earthquake
Residents did not pay taxes in 2010
Students given free public transport, discounts and educational equipment and exempt from Uni fees for 3 years
Homes took several years to rebuild and historic centres took 15 years to rebuild

Question 24

Give 2 social reasons why people continue to live at risk from tectonic hazard

Answer 24

People believe the chances of the hazard e.g. volcano occurring are very slim
Poor people (LEDCs) can't afford to move/live away from tectonic hazard as families, jobs and friends situated there

Question 25

Give 2 environmental reasons why people continue to live at risk from tectonic hazard

Answer 25

Basalt is found in volcanic areas and can be used in construction and to build roads
Volcanic soils are fertile as weathering of volcanic rock releases K into soil- essential for plant growth e.g. olives, nuts and fruit (Naples, Italy)

Question 26

Give 2 economic reasons why people continue to live at risk from tectonic hazard

Answer 26

World’s best coffee grown on volcanic soil in Columbia
In Iceland, Volcanoes provide cheap geothermal power (28% of it’s energy even used to heat pavements in Reykjavik)
Tourism is popular in areas (e.g. Mount Etna attracts thousands of tourists and jobs for locals)

Question 27

Describe how MONITORING can reduce the effect of tectonic hazards

Answer 27

Network of seismometers and lasers monitor earth movements
Can be used in early warning systems to give small but vital warning before earthquake occurs
Small earthquakes, escaping gas and changes in shape of volcano can be monitored by scientists meaning eruption is likely (bulges of magma in land)

Question 28

Describe how PREDICTION can reduce the effect of tectonic hazards

Answer 28

By monitoring movement of tectonic plates, scientists can forecast which areas should be prepared for one to occur
If volcanoes well monitored, can be predicted- gives people time to evacuate reducing injuries and death

Question 29

Describe how PROTECTION can reduce the effect of tectonic hazards

Answer 29

Buildings designed to withstand earthquakes (using reinforced concrete, special foundations that absorb earthquake’s energy)
Existing buildings/bridges can be strengthened (wrapping pillars in steel frames) so less likely to collapse under weight of falling ash or shaking from earthquake
Automatic shut off switches fitted to turn off gas/electricity supplies to prevent fires if earthquake is detected by monitoring system

Question 30

Describe how PLANNING can reduce the effect of tectonic hazards

Answer 30

Future developments planned to avoid areas most at risk from hazards
Emergency services can train/prepare for disasters (practice rescue from collapsed buildings/set up shelters) reducing number killed
People educated
Governments plan evacuation routes to get people out of dangerous areas quickly and safely. Reduces number killed or injured by things like fires, pyroclastic flows, mudflows
Emergency supplies can be stockpiled (blankets, clean water, food). If predicted, these stockpiles can then be moved close to areas likely to be affected

Question 31

What is the general atmospheric circulation model?

Answer 31

It shows how wind/air moves around the world. Air circulates/moves around in each hemisphere in three cells (from top- polar, ferrel, hadley, h, f, p). The winds are caused by the sun warming air more intensely at the equator and this warm air moves north and south to the poles

Question 32

Winds are part of global atmospheric circulation. What is wind and what is it caused by?

Answer 32

Large scale movements of air caused by differences in air pressure

Question 33

What are differences in air pressure caused by?

Answer 33

Differences in temperature between the equator and the poles. Winds move from the areas of high pressure to the areas of low pressure

Question 34

Warm rising air creates

Answer 34

a low pressure belt

Question 35

Cool falling air creates

Answer 35

a high pressure belt

Question 36

Describe what happens at the hadley cell

Answer 36

Warm air rises at the equator creating a low pressure belt with rising air, clouds and rain.
Air cools and moves 30 degrees north and south of the equator, then sinks creating a high pressure belt with no clouds and low rainfall

Question 37

What occurs as cool air reaches the ground surface and moves as surface winds back to the equator or towards the poles

Answer 37

Surface winds (trade winds) blow towards the equator
They blow from the SE in the southern hemisphere from the NE in the northern hemisphere
At the equator these trade winds meet and are heated by the sun- causing them to rise and form clouds
Surface winds towards poles are called westerlies and blow from NW in southern hemisphere to SW in northern hemisphere

Question 38

What occurs 60 degrees north and south of the equator (p/f)?

Answer 38

The warmer surface winds meet colder air from the poles
The warmer air is less dense than the cold air so it rises, creating low pressure
Some of the air moves back towards the equator and the rest moves towards the poles
At the poles the cool air sinks creating high pressure- the high pressure air is drawn back towards the equator as surface winds

Question 39

Describe the global distribution of tropical storms

Answer 39

Develop in the tropics (area between Tropic of cancer and Tropic of Capricorn)
Occur when tropical warm air rises to create an area of very low pressure

Question 40

Name for tropical storm west of carribean ish, north o equator and north america

Answer 40

Hurricanes

Question 41

Name for tropical storm south of equator australasia

Answer 41

Cyclones

Question 42

Name for tropical storm north of equator in asia/china/japan

Answer 42

Typhoons

Question 43

What are the conditions in which a tropical storm develops?

Answer 43

When sea temp is 27 degree or higher
When wind shear (difference in wind speed) between higher and lower parts of the atmosphere is low
Intense low pressure

Question 44

Cause of tropical storm

Answer 44

Warm moist air rises and condensation occurs releasing huge energy (LOW PRESSURE) increasing surface winds, cumulonimbus clouds and heavy rainfall
Storms move west because of easterly winds near equator
Period of calm with no wind/rain at eye of storm- sun appears so warm and air pressure very low
The earth’s rotation deflects the path of the winds causing them to spin
The storm gets stronger due to energy from the warm water so wind speed increases- lose strength over land and cooler water as not as much energy from warm water
Wind and heavy rainfall increase dramatically and temp drops and air pressure rises
Wind and rainfall subside

Question 45

What degree does most tropical storms occur between?

Answer 45

5 and 30 north and south of the equator- any further not warm enough
Majority in northern hemisphere over pacific in late summer and autumn when temp highest