8549025
Description
Mind Map by alex carpenter , updated more than 1 year ago
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Created by alex carpenter
over 7 years ago
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The Restless Earth
- fold mountains
- when tectonic plates collide, the sedimentary
rocks that have built up between them are
folded/forced upwards to form mountains.
these are formed at destructive plate
margins.
- example: Himalayas,
indian and eurasian
plates BOTH
continental, neither
subducted due to
density caused
upwards fold
- example: Himalayas,
indian and eurasian
plates BOTH
continental, neither
subducted due to
density caused
upwards fold
- fold mountains used to:
graze cattle, terraces
constructed to grow crops,
hydroelectric power
scource from high lakes,
forestery, mining for metal
ores, tourism.
- when tectonic plates collide, the sedimentary
rocks that have built up between them are
folded/forced upwards to form mountains.
these are formed at destructive plate
margins.
- tectonic plates
- the structure of the earth:
inner core (iron and nickel),
outer core (iron and nickel),
mantel (magma) and the
crust.
- oceanic crust - thicker and covers the ocean basins.
continental crust - lesser in density, covers 40% of the earth
and made of granite
- oceanic crust - thicker and covers the ocean basins.
continental crust - lesser in density, covers 40% of the earth
and made of granite
- the earths crust is
formed by plates.
heat rising and falling
in the mantle creates
convection currents,
these currents cause
the plates to move
- volcanoes are usually located
on or near plate boundaries,
most commonly destructive
and constructive.
- destructive plate boundaries
- oceanic and continental
plates move together,
oceanic plate is forced under
the lighter continental plate,
friction causes melting of
oceanic crust which causes
earthwqaukes and also
magma rises up to the
surface through cracks.
- example of this - Nazca plate forced under
South American plate.
- example of this - Nazca plate forced under
South American plate.
- constructive plate
boundaries - when
plates move apart from
each other, volcanoes
form as the magma
rises up to fill the gap
created.
- an example of this is the Mid
Atlantic Ridge.
- an example of this is the Mid
Atlantic Ridge.
- conservative plate boundaries -
when plates slide past each other in
opposite or the same directions but
at different speeds. but eventually
friction is overcome and causes
sudden movement causing shock
waves which produce earthquakes.
VOLCANIC ERUPTIONS CAN NOT
TAKE PLACE AT THESE MARGINS
- example of this is the
San Andreas fault.
- example of this is the
San Andreas fault.
- destructive plate boundaries
- oceanic and continental
plates move together,
oceanic plate is forced under
the lighter continental plate,
friction causes melting of
oceanic crust which causes
earthwqaukes and also
magma rises up to the
surface through cracks.
- volcanoes are usually located
on or near plate boundaries,
most commonly destructive
and constructive.
- the structure of the earth:
inner core (iron and nickel),
outer core (iron and nickel),
mantel (magma) and the
crust.
- volcanoes and volcanic eruptions
- formation of volcanoes :
1 - magma rises through
cracks or weaknesses in
crust . 2 - pressure
builds up inside. 3 -
pressure is released due
to plate movement and
magama xplodes to the
surface causeing an
eruption. 4 - the lava
from the eruption cools
to form the new crust. 5
- after several eruptions
the rock builds up and a
volcano forms.
- types of volcano: shield volcanoes
- usually found at constructive
boundaries, low with gently
sloping sides, eruptions tend to
be frequent yet relatively gentle.
composite volcanoes - made of
layers of lava and ash, found at
destructive boundaries, eruptions
usually pyroclastic flow.
- supervolcanoes - a volcano on a massive
scale. forms a depression (caldera), has a
ridge of higher land around it, eruptions
are hundreds of thousands of years apart.
results of an eruption are devastating,
1,000 km3 of material.
- Yellowstone (supervolcano) - last
eruption occured 630,000 years ago
and was 1,000 times bigger than the
Mount St Helens eruption. the large
volume of material from the last
eruption caused the ground to
collapse creating a caldera ( 55km
by 80km wide). the next eruption is
predicted to have worldwide effects.
- Yellowstone (supervolcano) - last
eruption occured 630,000 years ago
and was 1,000 times bigger than the
Mount St Helens eruption. the large
volume of material from the last
eruption caused the ground to
collapse creating a caldera ( 55km
by 80km wide). the next eruption is
predicted to have worldwide effects.
- supervolcanoes - a volcano on a massive
scale. forms a depression (caldera), has a
ridge of higher land around it, eruptions
are hundreds of thousands of years apart.
results of an eruption are devastating,
1,000 km3 of material.
- formation of volcanoes :
1 - magma rises through
cracks or weaknesses in
crust . 2 - pressure
builds up inside. 3 -
pressure is released due
to plate movement and
magama xplodes to the
surface causeing an
eruption. 4 - the lava
from the eruption cools
to form the new crust. 5
- after several eruptions
the rock builds up and a
volcano forms.
- earthquakes
- earthquake - shaking and vibration
of the earths crust due to
movement of the earths plates. they
can occur at any type of plate
boundary.
- when plates move next to eachother
and get stuck, pressure builds up and
when it is released an earthquake tends
to occur.
- the point in the crust where
the pressure is released is
called the focus, the point on
the earths surface is called
the epicentre.
- the point in the crust where
the pressure is released is
called the focus, the point on
the earths surface is called
the epicentre.
- the power of an earthquake is
measured using seismometer
which detects vibrations. the
strength (magnitude) of an
earthquake is measured using
the richter scale numbered
0-10, the higher the number
the higher the magnitude.
- Mercalli scale measures the
intensity of an earthquake by
analysing the effects and damage
caused by it.
- Mercalli scale measures the
intensity of an earthquake by
analysing the effects and damage
caused by it.
- effects of an earthquake (short-term) :
people killed or injured, homes
destroyed, shops and businesses
destroyed, lootings, damage to
transport and communications, fires
can spread due to gas pipes, damaged
wood areas, tsunamis and landslides
may occur
- effects of an earthquake (long-term):
disease may spread, rehousing and
refuge camps, high cost of rebuilding
settlements is high, important natural
and human landmarks can be lost/
- earthquake - shaking and vibration
of the earths crust due to
movement of the earths plates. they
can occur at any type of plate
boundary.
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