natural hazards Flashcards
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
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
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
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
how can earthquakes occur at constructive margins?
tension builds along the cracks in the plates as they move away from each other
how can earthquakes occur at destructive margins?
tension builds up when one plate gets stuck as it moves past the other
how do earthquakes occur at conservative margins?
tension builds up when plates that are grinding past each other get stuck
how does an earthquake happen at all the margins?
- plates eventually jerk past each other - sending out shockwaves
- these vibrations are the earthquake
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
what is used to measure an earthquake?
- the moment magnitude scale
- logarithmic scale
why do volcanoes occur at constructive margins?
magma rises from the gap created by the plates moving apart - forming a volcano
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
