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Flashcards in natural hazards Deck (12)
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1

how can prediction reduce the effects of tectonic hazards?

- earthquakes - cannot be reliably predicted, but scientists can forecast where they may occur by monitoring the movement of tectonic plates

- volcanic eruptions - can be predicted if scientists monitor volcanos closely

2

how can monitoring reduce the effects of tectonic hazards?

- earthquakes - seismometers and lasers monitor earth movements, can be used to give a vital amount of warning before a large earthquake

- volcanic eruption - scientists can monitor the tell-tale signs that come before an eruption. ex. escaping gas, change in shape of volcano

3

how can protection reduce the effects of tectonic hazards?

- earthquakes - new buildings can use reinforced concrete that absorbs an earthquake's energy

- existing bridges and buildings can be strengthened with steel frames so they're less likely to collapse

- automatic shut-off switches can turn off gas and electricity supplies to prevent fires

- volcanoes - buildings strengthened - less likely to collapse under weight of ash

4

how can planning reduce the effects of tectonic hazards?

- future developments can avoid high-risk areas
- emergency services can prepare
- people can be educated to know what to do in the event of a hazard
- governments can plan evacuation routes
- emergency supplies can be stockpiled

5

how can earthquakes occur at constructive margins?

tension builds along the cracks in the plates as they move away from each other

6

how can earthquakes occur at destructive margins?

tension builds up when one plate gets stuck as it moves past the other

7

how do earthquakes occur at conservative margins?

tension builds up when plates that are grinding past each other get stuck

8

how does an earthquake happen at all the margins?

- plates eventually jerk past each other - sending out shockwaves
- these vibrations are the earthquake

9

what are constructive margins?

- where two plates are moving away from each other
- magma rises from the mantle to fill the gap and cools creating new crust

10

what is used to measure an earthquake?

- the moment magnitude scale
- logarithmic scale

11

why do volcanoes occur at constructive margins?

magma rises from the gap created by the plates moving apart - forming a volcano

12

why do volcanoes occur at destructive plate margins?

- denser oceanic plate moves down mantle where it melts
- pool of magma forms - then rises through cracks in crust called vents
- magma erupts forming a volcano