natural hazards

Question 1

how can prediction reduce the effects of tectonic hazards?

Answer 1

• 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

Question 2

how can monitoring reduce the effects of tectonic hazards?

Answer 2

• 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

Question 3

how can protection reduce the effects of tectonic hazards?

Answer 3

• 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

Question 4

how can planning reduce the effects of tectonic hazards?

Answer 4

• 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

Question 5

how can earthquakes occur at constructive margins?

Answer 5

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

Question 6

how can earthquakes occur at destructive margins?

Answer 6

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

Question 7

how do earthquakes occur at conservative margins?

Answer 7

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

Question 8

how does an earthquake happen at all the margins?

Answer 8

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

Question 9

what are constructive margins?

Answer 9

• where two plates are moving away from each other

- magma rises from the mantle to fill the gap and cools creating new crust

Question 10

what is used to measure an earthquake?

Answer 10

• the moment magnitude scale

- logarithmic scale

Question 11

why do volcanoes occur at constructive margins?

Answer 11

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

Question 12

why do volcanoes occur at destructive plate margins?

Answer 12

• 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