Natural Hazards Flashcards

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1
Q

3 different types of natural hazards

A

Atmospheric/climatic
- storms
- flooding
- tornadoes
- droughts

Hydrological
- floods
- tsunamis

Tectonic
- earthquakes
- volcanoes

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2
Q

4 factors that increase the risk of natural hazards

A

Climate change
- ⬆️ temp
- ⬆️ pressure
- ⬆️ sea levels
Farming
- flat land = floods
- methane = climate change
Poverty
- 🔻money for preparation/protection
- 🔻lack of education
- 🔻emergency services
Urbanisation
- ⬆️ impermeable surfaces
- ⬆️ lives at risk

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3
Q

Which type of tectonic plate is denser?

A

Oceanic

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4
Q

Theory of continental drift by Alfred Wegener

A

200m years ago continents were merged into a supercontinent called Pangea
Proof:
- edges of continents match the shapes of others
- similar patterns of rocks and fossils where continents would’ve met

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5
Q

What are convection currents?

A

A movement within the Earth’s mantle caused by the heat of the core.
- hot magma rises (heated by earths core)
- cools when it reaches earth’s surface and sinks
- causes slab pull of the tectonic plates above meaning they sink and pull apart (follow the direction of the currents)

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6
Q

Constructive plate boundary

A

2 plates moving away from each other.
- causes magma to erupt between them
- creates a shield volcano

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7
Q

Destructive plate boundary

A

Oceanic crust is denser and sinks under the continental crust
- caused by convection currents, so the plates move towards each other
- then the oceanic crust subducts (creating a subduction zone)
Creates earthquakes

Leaves a composite volcano
- the sinking plate in the mantle melts to form magma
- the pressure of the magma builds up beneath the Earth’s surface
- magma escapes through weaknesses in rock through a composite volcano
(eruptions are often violent, with lots of steam, gas and ash)

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8
Q

What is the contrasting earthquake case study?
(flashcards in a separate deck)

A

Chile and Nepal

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9
Q

How to reduce the risk of tectonic hazards? (3 ways)

A

Prediction
- using seismometers to monitor tremors
- monitor gas emissions (⬆️ quantity signals start if eruption)

Preparation
- earthquakes drills
- emergency kits
- education
- structurally sound buildings

Protection
- steel frames which can sway
- rubber shock absorbers
- open areas for easy evacuation

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10
Q

Where are earthquakes found?

A

Along all types of plate margins

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11
Q

Where are volcanoes found

A

Only along constructive and destructive margins.
Most volcanic activity happens along the ‘ring of fire’ (a group of volcanoes located along the Pacific plate margin

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12
Q

Conservative plate boundary

A

2 continental plates slide past each other and cause an earthquake due to friction

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13
Q

Collision plate boundary

A

2 continental plates move towards each other and buckle up which creates fold mountains

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14
Q

Why do people live near volcanoes? (4)

A

Farming
- fertile soils from the ash & minerals
- eg. Mt Etna sicily

Heating
- geothermal energy for a low cost
- eg. Iceland

Mining
- lava from deep down contains minerals
- eg. Gold or silver

Tourism
- lots of jobs are created
- eg. Blue Lagoon

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15
Q

High pressure (weather)

A

Thing depressing! 😞
Cold, dense, sinking air
- causes anticyclones (high winds)
- dry air (no evaporation- cold🥶)
- settled weather
DRY AND CLEAR DAYS ☀️🥶

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16
Q

Low pressure (weather)

A

Think free and floaty! 😊
Hot, low density, rising air
- moisture (from evaporation- warm 🥵)
- condenses and makes clouds
- this creates depressions
CLOUDY & RAINY DAYS ☔️🌧

17
Q

What is the atmospheric circulation model?

A

Explains circulation and heat distribution, and the movement of air across our planet

18
Q

What is the order of the cells in the atmospheric circulation model
(and which way do they circulate?)

A

Polar
🔄Ferrel Ferrel🔁.

🔁Hadley Hadley🔄.

    0️⃣ degrees

🔄Hadley Hadely🔁.

🔁Ferrel Ferrel🔄

              Polar
19
Q

What is the Coriolis effect?

A

Winds are distorted by earth’s rotation (which causes tropical storms!)

20
Q

Hadley cell

A

Intensely hot (on earth’s core) ♨️
- low pressure (rising air) - hot, humid, rainly (TRF🎋)
- then air begins to sink at 30
- higher pressure - deserts 🏜 with low rainfall

21
Q

Ferrel cell

A

Unstable weather conditions
- mixture of warm air (tropics) and cold air (poles)

22
Q

Polar cell

A

Sinking air = high pressure
COLD 🥶