natural hazards Flashcards
what is a hazard
something that poses risk to people and the environment
what is a natural hazard
a natural event which poses risks to people and the environment
what is natural
naturally occurring, not caused by people
4 types of hazards
geological
biological
meteorological
hydrological
examples of geological hazards
earthquakes, landslides, tsunamis and volcanoes
examples of biological hazards
disease epidemics and insect/animal plagues
e.g. covid-19
examples of meteorological hazards
tropical storms, droughts, wildfires and extreme temperatures
examples of hydrological hazards
avalanches and floods
what is a hazard risk
chance or probability of being affected by a natural event
5 things that increase hazard risk
location in the world
economic development
urbanisation
time of event
climate change
examples of hazard risk
people who live in low lying areas are more at risk from flooding
people who live in coastal regions are more at risk of tropical storms
people who live in urban areas are more at risk from earthquakes
if an earthquake happens during rush hour, more people will be affected
people living in LICs are less able to prepare for natural hazards like earthquakes
why can HICs cope with natural hazards better
HICs tend to be better prepared for natural hazards because they can afford good equipment to monitor, predict and evacuate areas at risk
how does earthquake on destructive plate boundary affect more people
if an earthquake at a destructive plate boundary causes a tsunami, more people will be impacted
what is the crust
above mantle
earths hard outer shell
surface we’re living on
thin- 4-7 miles deep
what is the mantle
layer above the outer core
1800 miles thick
makes up 80% of the earths total volume
what is the outer core
hot —> temps reaching 3700 degrees
1370 miles thick
what is the inner core
centre of earth that’s solid (iron and nickel)
780 miles thick
describe continental crust
land on top of it
less dense (lighter)
thick
e.g. north american plate
describe oceanic crust
ocean on top of it
heavy and dense
thinner
e.g. pacific plate
what is a convection
heat rises and falls inside the mantle which creates convection currents generated by radioactive decay
the convection currents move the plates
what is a ridge push
when plates move apart (constructive boundary), the magma rises from the mantle
magma cools and creates new, hot and dense rock
it pushes the old rock out of the way
this creates a ridge in the crust
what is a slab pull
gravity pulls the old rock into the mantle because the rock has become colder and denser
what is a constructive margin
2 plates move apart, magma rises up to fill the gap —> causes volcanoes at this type of boundary
however, since the magma can espace easily at the surface, the volcano does not erupt with much force
earthquakes are also found at constructive boundaries e.g. mid atlantic ridge
what hazards are found at constructive plate boundaries
earthquakes and volcanoes
what is a destructive plate boundary
plates move towards each other and 1 is subducted under the other
found where a continental plate meets an oceanic plate
oceanic plate descends under the continental plate because it is denser
as plate descends, it starts to melt due to friction caused by the movement between plates
melted plate is now hot, liquid rock (magma) —> it rises through gaps in the continental plate and if it reaches the surface, the liquid rock forms a volcano
example of destructive plate margin
andes mountains in south america
what is it called if subduction does not take place
collision boundary
what hazards are found on the destructive plate boundary
earthquakes, tsunamis and volcanos