Global hazards

Question 1

Natural Hazard

Answer 1

• An extreme natural event or process that can lead to loss of life and/ or damage to property and severely disrupts human activity

Question 2

What causes a tectonic hazard?

Answer 2

• The movement of the Earth

Question 3

What causes a Climate Hazard?

Answer 3

• Processes in the atmosphere

Question 4

Weather

Answer 4

• The day to day conditions of the atmosphere involving, for example, temperature, precipitation and wind

Question 5

Climate

Answer 5

• The average weather conditions recorded over a period of at least 30 years

Question 6

Atmosphere

Answer 6

• The air above our heads
• Mass of swirling gases, liquids and solids, such as CO2, O2, water vapour and droplets and ash

Question 7

Circulation

Answer 7

• Circular air movements called cells.
• These cells all join together to form the overall circulation of the Earth’s atmosphere

Question 8

What are the 3 circulation cells?

Answer 8

• Hadley Cell
• Ferrel Cell
• Polar Cell

Question 9

What is wind?

Answer 9

• The movement of air from an area of high to low pressure
• The greater the difference in pressure, the greater the winds

Question 10

Trade winds

Answer 10

• Winds that blow from high pressure belts to low pressure belts
• Used by trading ships to sail
• Mt. Washington has winds up to 372 km/hp

Question 11

Katabatic winds

Answer 11

• Caused by air flowing downhill
• In Antarctica, large sloping ice sheets contribute to wind speeds of over 320 km/h

Question 12

Jet stream

Answer 12

• Winds that are high in the atmosphere
• Speeds of 225 km/h recorded on Mr. Everest

Question 13

Tropical Storms

(winds)

Answer 13

• Very strong rotating winds
• Start smaller but develop into strongest winds ever recorded
• Die out when they reach land
• Highest speed recorded was 408km/h on Barrow Island in Hurricane Olivia in 1996

Question 14

The Albedo effect

Answer 14

• How much a surface reflects or absorbs the Sun’s rays
• The more reflective, the less heat it can hold

Question 15

What happens during El Niño?

(bullet points)

Answer 15

• Trade winds in the western Pacific Ocean weaken, stop or reverse
• The piled up water around Australia and Indonesia moves its way back towards the eastern Pacific Ocean
• Water in eastern Pacific Ocean gets 6-8 degrees warmer than usual

Question 16

What happens during El Niño?

(high pressure, low pressure etc.)

Answer 16

High pressure- Australia
Low Pressure- Peru
Rainfall- South America
Drought- Australia
Flooding- Peru
Trade winds- Weaken, stop or reverse

Question 17

What happens during a normal year?

(bullet points)

Answer 17

• Trade winds blow westwards over Pacific Ocean, pushing warm water from Peru to Australia
• In the eastern Pacific, off the coast of Peru, the thermocline is especially low

Question 18

What happens during a normal year?

(high pressure, low pressure etc.)

Answer 18

High pressure- South America
Low Pressure- Australia
Rainfall- Australia
Drought- N/A
Flooding- N/A
Trade winds- East to West

Question 19

What happens during La Niña?

(bullet points)

Answer 19

• Doesn’t always come after an El Niño year
• Unusually cold sea surface temperature in eastern tropical Pacific
• More extreme version of a normal year

Question 20

What happens during La Niña?

(high pressure, low pressure etc.)

Answer 20

High pressure- South America
Low Pressure- Australia
Rainfall- Australia
Drought- Peru
Flooding- Australia
Trade winds- East to West

Question 21

Thermocline

Answer 21

An abrupt temperature gradient in a body of water such as a lake or ocean, above and below the thermocline the water is at different temperatures

Question 22

Drought

Answer 22

A period of below average precipitation where the abnormally dry weather leads to a shortage of water, which can have a negative effect on vegetation, animals and people over a large area

Question 23

Arid

Answer 23

• Lacking moisture
• Very dry

Question 24

Causes of droughts

Answer 24

Human causes:
- Global warming
- Soil erosion
- Deforestation
- Irrigation
- Population increase
- Urbanisation

Physical causes:
- El Niño
- Climate change
- Position of ITCZ (Inter- tropical convergence zone)

Question 25

ITCZ meaning

Answer 25

Place where the Hadley cells meet

Question 26

Tropical Storm

Answer 26

- Areas where air is rising and causing extreme low pressure on the Earth's surface - This creates powerful spiralling winds that last 6-14 days with wind speeds of over 120km/h

Question 27

What are tropical storms called in the Atlantic and Pacific?

Answer 27

Hurrricanes

Question 28

What are tropical storms called in the Northwestern Pacific?

Answer 28

Typhoons

Question 29

What are tropical storms called in the Indian Ocean and the Southwestern Pacific?

Answer 29

Tropical cyclones

Question 30

Inner core

Answer 30

- Solid metal - Radius of 1220km - Made up of iron and nickel - Hotter than the surface of the Sun at 6000 degrees Celsius - Pressure of other layers compresses inner core

Question 31

Outer core

Answer 31

- Made up of iron and nickel - 2300km thick - 4400 degrees celsius - Less pressure on it so the metal that it is made up of is liquid

Question 32

Mantle

Answer 32

- Split into lower mantle (mesosphere) and upper mantle (asthenosphere) -2900km thick (84% of Earth's volume) - Made up of magnesium, iron, silicon and oxygen - Between 1000 and 3700 degrees celsius so in the upper mantle, the solid is mostly putty

Question 33

Crust

Answer 33

- Thinnest layers of the Earth - Oceanic crust- Made from balsamic type rocks rich in magnesium and aluminium - Continental crust- Made of granite type rock, rich in silico and aluminium

Question 34

Tectonic plates

Answer 34

- Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core - The plates act like a hand and rigid shell compared to Earth's mantle

Question 35

Plate Boundary

Answer 35

- The line where different plates meet - There are 4 types of plate boundaries: Constructive, Conservative, Destructive and Collision

Question 36

Earthquake

Answer 36

- The sudden release of energy that is the result of the movement of layers of rock in the Earth's crust

Question 37

How do earthquakes happen?

Answer 37

- Rough edges of plates try to move past each other and get stuck, building up energy, which is then released when the plates slip - Energy is released as seismic waves

Question 38

How are earthquakes measured? (most known technique)

Answer 38

Richter Scale: - Open- ended scale - Measures magnitude of a tremor - Uses seismometer - Logarithmic scale ( so a 2 is 10x more powerful than a 1 and a 3 is 100x more powerful than a 1 etc.)

Question 39

How are earthquakes measured? (less known technique)

Answer 39

Mercalli Scale: - Based on what people felt/ saw during the earthquake - Subjective scale - Uses Roman Numerals

Question 40

Richter Scale (Advantages)

Answer 40

- Quantitative data - Objective data - Accurate - Factual

Question 41

Richter scale (Cons)

Answer 41

- Computer/ Seismometer could malfunction

Question 42

Mercalli Scale (Pros)

Answer 42

- Cheaper - Qualitative data

Question 43

Mercalli Scale (Cons)

Answer 43

- Not factual - People may have different opinions and experiences with earthquake based on where they were when it happened - Takes longer to get data - Subjective

Question 44

How does a tsunami form?

Answer 44

1- Eurasian plate gets dragged down/ subducted by the Pacific plate grinding under it 2- It gets pulled down so much that it springs back up when an earthquake happens 3- This causes a four-mile deep mass of water to thrust upwards 4- When the dome collapses, strong waves of around 3 feet high travel outwards at a blistering speed, creating a tsunami 5- The tsunami gets taller as it gathers more water as the waves get closer to the coast