The challenge of natural hazards: tectonic hazards Flashcards
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
what are the primary effects of earthquakes
- deaths/injury
- infrastructure destroyed
- gas + water + electric cables are broken
what are the secondary effects of earthquakes
- slowing economy
- blocked infrastructure
- burst water pies lead to a shortage of fresh water, poor sanitation
- illness
- fires due to gas +fallen electricity
what are the immediate responses to a tectonic hazard
people are going to evacuate
what are the long term responses to a tectonic hazard
rebuilding infrastructure
what are the immediate responses for tectonic hazards
- issue warnings after a major earthquake due to the risk of after shocks or after volcanoes in case they continue to erupt
- rescue teams searching for survivors - often lic’s rely on support from hic’s
- providing treatment to injured people
- food, drink, shelter provided
- recovering bodies - stop spread of disease
- extinguishing fires
what are the long term responses for tectonic hazards
- rebuilding, repairing properties
- rebuilding + repairing infrastructure
- improving building regulations
- resettling people
- restoring utilities e.g. water, electricity
- install monitoring equipment
where is Chile located
Chile is a HIC in South America which lies on the south west coast.
how strong was the Chile earthquake
it was an earthquake with a magnitude of 8.8
when did the earthquake hit Chile
2010
what was the cause of the earthquake
a destructive plate margin = Nazca plate subjected under South American plate. A tsunami occurred as it happened over the pacific and displaced lots of water
what were the primary effects of the earthquake
- around 500 killed and 12,000 injured
- 800,000 people affected overall
- many buildings destroyed - homes, schools, ports, hospitals, airport
- water, electricity, communications lost
- well - constructed buildings were left standing after the earthquake
- cost of USD $3 billion
what were the secondary effects of the earthquake
- landslides - damaged 1500km of roads
- debris blocked roads - cutting of rural communities
- tsunami - destroyed coastal towns, ports, other countries
- fires broke out - pipes burst
what were the immediate responses to the event
- emergency services, search + rescue, emergency field hospitals
- 24 hours = temporary repairs made to roads - reconnected capital for response teams
- temporary shelters
- international aid
- power +water restored to 90% of homes within 10 days
- USD $60mil raised
