global hazards Flashcards
(82 cards)
can earthquakes happen in all plate boundaries?
yes
what are the four main plate boundaries?
constructive, destructive, collision and conservative
How is friction an important factor in the build up to an earthquake?
Because the two plates catch on each other which causes the friction. This friction builds up until the rocks can no longer handle it then they jolt and move forward. This jolt is the earthquake and it releases energy through seismic waves
what are seismic waves?
vibrations generated by an earthquake
what is the focus of an earthquake?
the point where the ground moves, which can be at different depths within the plate
what is the epicentre of an earthquake?
the point on the surface of the land above the focus
what is a primary effect?
something that is directly caused by the disaster
what are examples of primary effects of earthquakes?
ground shaking, surface displacement, building and infrastructure damage, landslides
what are examples of secondary effects of an earthquake?
fires, human casualties, impact on economy, tsunami, aftershocks
what are four factors that change how strongly the ground shakes during an earthquake?
the strength of the earthquake itself, how deep the focus is, how far the location is from the epicentre and what the ground is made from
how does the type of rock change the effects of an earthquake?
softer rocks shake more easily and become fluid, but stronger rocks will withstand more stress before fracturing
what is liquefaction?
when rocks shake so violently that they turn into a liquid state, shockwaves cause deeper groundwater to rise to the surface and particles to shake together to become a fluid
what factors led to the Haiti earthquake being so deadly?
buildings were not built strong enough (densely populated - domino affect with houses collapsing on each other), city was close to fault line, lack of knowledge + preperation, emergency services problems, lack of warning systems
in a destructive plate boundary, are the two plates the same?
no, one of the plates is a continental plate and the other is an oceanic
in a constructive plate boundary, are the two plates the same?
yes, they are both continental plates
in a conservative plate boundary, are the two plates the same?
yes, they are both continental plates
in a collision plate boundary, are the two plates the same?
yes, they are both continental plates
what is a hot spot?
a large plume of hot mantle material rising from deep within the earth (a place where the magma rises up through the crust)
what is cause of earthquakes?
sudden movement along faults within the Earth
what are the hazards in a constructive boundary?
earthquakes, volcanoes can be made
what is the hazard in a collision zone?
earthquakes
what is the hazard in conservative boundary?
powerful earthquakes
what is subduction?
where the oceanic plate is forced underneath the continental plate
what plate margin does subduction occur in?
destructive plate boundary