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C2a) the structure of the Earth
The outer layer of the Earth is made from tectonic
plates. The Earth's crust and upper part of the
mantle are broken into large tectonic plates.
It has taken millions of years for the continents to
Convection currents in the mantle cause tectonic
plates to move.
The coast of South America and west coast of Africa matching up helped people believe in
Wegener's theory about Tectonics. (Jigsaw puzzle). Pangaea (super continent, all earth)
The lithosphere is made of the crust and outer part of the mantle that lies underneath. It is
relatively cold and rigid. The lithosphere is broken into large pieces called tectonic plates.
Seismic waves are produced by movements of Earth's crust such as earthquakes and volcanic
eruptions. It's also due to the shifting of tectonic plates, when they rub against each other, it
causes seismic disturbances. If they occur in the oceans, or run into the oceans, they can
cause Tsunamis which can travel over great distances.
Further down there is a hotter layer called asthenosphere.
Energy from the Earth's core transferred by convection currents in the mantle
Slowly moves the tectonic plates
Causes seismic waves by the movement
Causes earthquakes and volcanic eruptions (the
magma from core).
Tectonic plates can:
Scrape sideways past each other
KNOWN AS SUBDUCTION
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Igneous rock slow cooling large crystals intrusive formed beneath the earth's
surface where the temperature is high.
Igneous rock fast cooling small crystals extrusive forms on the earth's surface
Magma (inside volcano), Lava (outside volcano)
Runny lava fairly Safe
Thick and sticky lava dangereous (explosive)
People take the risk of living near volcanoes because it makes a rich soil that is good for
growing crops.…read more