Plate Tectonic Flashcards

1
Q

how is the crust divided

A

the crust is divided into several large pieces called plates
it is unstable because plates move
😊slowly

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2
Q

name the way plates move

A

together destructive and collision
apart constructive
past each other conservative

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3
Q

how many types of crust are there

A

2 continental and oceanic

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4
Q

oceanic crust

A

5-10km thick
dense
sinks when is subducted by continental
oldest is 180 million years old
forms constantly at constructive plate boundaries
destroyed at destructive plate boundaries

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5
Q

continental

A
25-100km 
less dense 
doesn't sink
very old 3-4billion years old 
no crust not form 
cannot be destroyed
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6
Q

plate theories described the structure of the earth’s layers

A
inner core 
solid hot up to 5000oc
outer core 
liquid iron and nickel 
mantle 
soft molten rock about 3000oc nickel and iron 
crust
hard outer shell separated into plate margins
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7
Q

what happens inside the earth

A

heat from core gives convection currents in the mantle
very slow
causes plates to move
causes earthquakes and volcanoes to set off

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8
Q

magma

A

liquid rock

melted due to the earth’s core heat intensity

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9
Q

where do earthquakes and volcanoes happen

A

around plate boundaries
causes by friction of two.plates
or.molten rock magma rising to the surface of earth

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10
Q

why do earthquakes happen

A

occur due to stresses build up between the plates as one passes each other
plates are not smooth so they snag and grind each other allowing energy to.build up
when plates move seismic waves is released from energy

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11
Q

what is the focus

A

the focus is the place is where the earthquake is occurring

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12
Q

what is the epicentre

A

the epicentre is above on the surface of the earth where the epicentre resides

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13
Q

what is a volcano

A

they are mountains that can explode with violent conquences

volcanoes are landforms that are from hot liquid magma bring forced up from the earth’s crust through a vent

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14
Q

how many types of volcanoes are there

A

2

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15
Q

what are composite volcanoes

A
found ate destructive plate boundaries
steep sided layers of ash and lava 
viscous magma 
cools quickly
very explosive
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16
Q

shield volcanoes

A
found at constructive plate boundaries 
dome shape 
sloping sides 
runny magma flows a long distance 
gentle explosions
17
Q

destructive plate boundaries

A

oceanic meets continental moving towards each.

dense oceanic is subducted by continental
it melts and produces andesite

sinking plate can stick to continental,
pressure builds up against friction causing earthquakes
e.g Pacific and eurasian plates

18
Q

constructive plate margins

A

two oceanics plates move apart
new oceanic crust is created constantly in the gap as the magma cools
runny magma shield volcanoes
earthquakes due to friction as plates tear apart
n American and eurasian plates

19
Q

conservative plates

A

plates move by either in the same or different directions
slide pass each other causing friction earthquakes
no 🌋 volcanoes
Pacific and n American plates

20
Q

collision 💥

A

fold mountains are created
two continental plates moving towards each other
non of the plates sinks as they both have similar densities
plates buckle to form mountains e.g. himalayas
no volcano
indo-australian and eurasian plates

21
Q

primary effects of tectonic hazards

A
these are things that happen during the tectonic hazards sure such as :
buildings collapsing
injuries 
electricity and water supplies cutbacks
homelessness
22
Q

secondary effects of tectonic hazards

A

these are things that happen afterwards such as
fires
landslides
tsunamis