Natural hazards Flashcards
(40 cards)
what are natural hazards?
natural events that threaten people or have the potential to cause damage, destruction and death
what are the types of hazards?
tectonic and weather hazards
give some examples of tectonic hazards
earthquakes
tsunamis
volcanic eruptions
mass movement
coastal flooding
what are some weather hazards?
wind
hail
snow
drought
heat wave
forest fire
erosion
tropical storms
what are the factors affecting risk from a natural hazard
urbansiation- densley populated areas are at greater risk
poverty- poorer people are forced to live in areas at risk or build unsafe housing
farming- rivers can make soil very fertile so poeple like to live here in the low lying areas putting them more at risk
climate change-a warmer world means more energy in the atmosphere resulting in more intense storms or hurricanes which can lead to flooding or droughts
what are the layers of the earth starting from the outside?
crust
mantel
outer core
inner core
what are the 2 types of tectonic plates that you can get?
oceanic and continental
where do the plates move on a constructive plate boundry?
away from each other
where do the plates move on a destructive plate boundry?
the oceanic plate subducts under the continental as its the densest
where do the plates move on a conservative plate margain?
the slide alongslide eachother
where do the plates move on a collsion plate boundary?
two continental plates move into eachother and collide
give an example of each plate boundary
constructive- north american and eurasion plates (mid atlantic ridge)
destructive- nazca and south american plates
conservative- pacific and north american plates (san andreas fault)
collision- indian and eurasion plates (himalayas)
what landform is formed at each boundary?
collsion- fold mountains
conservative- fault lines and earthquakes
constructive- volcanoes
destructive- volcanoes, earthquakes and ocean trenches
what is ridge push?
the force created when convection currents (less dense magma rising to the surface) push the plates up and out, away from eachother allowing magma to rise and create new crust
what is slab pull?
when the force of gravity is pulling a subducted plate to the centre of the earth
how are volcanoes formed on constructive plate margains?
strong convection currents drag the tectonic plates away from eachother allowing magma to rise and then cool forming new crust and a volcano
how are volcanoes formed on destructive plate margains?
when an oceanic plate and a continental plate are ulled toward eachother due to convection currents the oceanic plate is subducted into the mantel as its the densest.This could also form an ocean trench. The subducted plate is melted but then rises along the fault lines due to pressure it bursts through the crust to form a volcano
why would you live in a hazardous area?
faming- ash from volcanoes makes fertile land
tourism means you can make money
jobs due to tourism
valuable minerals
access to geothermal energy
what are convection currents?
the circulation or materials caused by different densities
less dense molten rock rises to the top of the mantel and then splits off and sinks as it cools due to it becomes more dense again to forming an umbrella shaped movement
how are earthquakes measured?
the richter scale which measure the amount of energy released by the earthquake and the mercalli scale measures the damage done by the earthquake
what are the vibrations sent out by an earthquake called?
shockwaves
how do earthquakes happen?
what are the three ways of minimising the risk of an earthquake?
planning, predicting and protecting/preparing
give examples of how you can plan for an earthquake
fastening heavy furniture and objects down so they can’t fall over
delare a natioanl training day where people practise earthquake drills
issue checklists to people to help them plan for earthquakes in their homes, at work or schools
ensure people have kits ready with essentials in them
