Natural Hazards Flashcards
what is a natural hazard
a natural event that threatens people or has the potential to cause damage, destruction and death
hazard risk
the probability that a natural hazard may take place
natural disaster
A natural hazard turns into a natural disaster when it starts to affect people’s lives. HAZARDS COULD AFFECT LIVES BUT DISASTERS DO!!!
Biological hazard
caused by living things
Geomorphological hazard
created on the Earth’s surface
tectonic hazards
involves the movement of tectonic plates
Atmospheric hazard
created by weather conditions / made worse and more frequent by climate changes
distribution questions
overall where they are
examples!
Constructive plate boundary
- 2 plates moving apart
- when this happens, the magma from the mantle rises up to make new land in the form of flat shield volcano
- the movement of the plates over the mantle can cause earthquakes
destructive plate boundary
- oceanic and continental plate (usually)
- the plates move towards each other (due to convection currents) and this movement can cause earthquakes.
- As the oceanic plate is forced beneath the c plate, pressure builds up and when this is released an earthquake happens, as seismic waves are sent out.
- As the plates collide, the denser oceanic plate is subducted beneath the lighter continental plate
- When the plate sinks into the mantle, it melts to form magma.
- Newly formed magma is less dense than that in the mantle, and so it rises up through cracks in the crust and reaches the surface where it erupts to form volcanoes.
- If 2 continental plates collide, neither can sink and so the land buckles upwards to form fold mountains. This is called collision margin and earthquakes can occur at collision margins.
conservative plate boundary
- plates move past each other (due to CONVECTION CURRENTS)
- As the plates move, friction occurs and plates become stuck
- Pressure builds up as the plates are still trying to move
- when this pressure is released, it sends of huge amounts of energy, causing an earthquake
- NO VOLCANOES.
what are primary effects?
primary effects actually happen during the event. INITIAL IMPACT
what are secondary effects?
secondary effects happen from a short time to a long time later. AFTER EFFECTS
Drop, Cover, Hold on
Drop to the floor, cover your head, and hold on to something
What is a volcano?
an opening in the earths’s crust from which lava, ash and gases erupt.
Active volcano
A volcano which has erupted recently
Dormant volcano
A volcano which has not erupted recently but MAY erupt again.