The challenge of natural hazards: tectonic hazards Flashcards
(38 cards)
what is a natural hazard
extreme natural events that cause loss of life, extreme damage to property and disrupt human activity.
define hazard risk
looking at which areas in the world will be the most at risk from a natural hazard.
what are the 4 factors effecting hazard risk
climate change, urbanisation, level of development and land use
how does climate change effect hazard risk?
places at risk from natural hazards will be at a greater risk as climate change will increase these
how does urbanization effect hazard risk
more people = more people at risk
how does level of development effect hazard risk
high level = can prevent hazards and the affects from them more efficiently. more educated
how does land use effect hazard risk
changes in land e.g deforestation, urbanization can increase hazard risk for climate and geomorphological hazards
name the the structure of the earth in order
crust (lithosphere), asthenosphere, mantle, outer core, inner core
what are the characteristics of an oceanic plate
very dense, thin and much newer
what are the characteristics of a continental plate
much lighter, thick and older
what are the differences between the lithosphere and asthenosphere
lithosphere = solid, old crust
asthenosphere = semi-liquid, moves
what are the 4 pieces of evidence for the theory of continental drift and explain them
mountains - this shows that the plates get pushed into each other
jigsaw - the continents all fit together
fossils - the same kind of fossils have been found on opposite sides of the world, showing they were connected
geology - geology is identical in countries and climates no where near each other
what is a plate margin
the point where two or more plates meet. It is at these locations where earthquakes, volcanoes and fold mountains form.
what is the direction of plate movement, physical processes and natural events (earthquakes/volcanoes) for a constructive plate margin.
direction = away from each other
physical processes = convection currents move in opposite directions - ridge push
natural events = earthquakes, shield volcanoes
what is the direction of plate movement, physical processes and natural events (earthquakes/volcanoes) for a destructive plate margin.
direction = towards each other, oceanic + continental
physical processes = subduction, slab pull
natural events = earthquakes, volcanoes (composite)
what is the direction of plate movement, physical processes and natural events (earthquakes/volcanoes) for a conservative plate margin.
direction = opposite directions - rub against each other, past each other
physical processes = friction builds and then gets released
natural events = earthquakes
where do volcanoes and earthquakes happen?
constructive plate margins, pacific ring of fire (destructive), hot spots
why do volcanoes and earthquakes occur at constructive plate margins
boundaries are forced apart forcing magma up creating volcanic activity
why do volcanoes and earthquakes occur at destructive plate margins (pacific ring of fire)
oceanic plate gets pushed under continental it melts, friction + pressure builds forcing magma upwards
why do volcanoes and earthquakes occur at hot spots
magma bloom and magma mixes with ocean, to create volcanoes, earthquakes and new land
what is a primary effect of a tectonic hazard
things that happen immediately as a result of a hazard
what is a secondary effect of a tectonic hazard
things that happen in the hours, days and weeks after the initial hazard.
what are the primary effects of volcanoes
- farmland + property destroyed
- livestock killed/ injured
- air travel restricted or cancelled due to ash in the atmosphere
- contaminated
what are the secondary effects of volcanoes
- emergency services struggle to arrive
- glaciers melt = flooding
- lahars = rainfall + melt water mix with volcanic ash to create mudflows
- tourism increases with people interested in seeing volcanoes
- ash provides fertile foil for agriculture
