Geography unit 2 tectonic landscapes 2

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Divergent/constructive plate boundaries - two plates moving away from each other e.g- North American plate moving away from Eurasian plate causing Atlantic ocean to widen 3cm a year.
Caused by convection currents creating a mid ocean ridge. Magma rises to fill the gap so forms new land. Iceland is an example of this, it was not there 2 million years ago.
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Conservative/ transform boundaries - where plates move alongside eachother.
No new crust is created or destroyed + no landforms form. But can cause violent earthquakes. E.g- the San Andreas Fault in California marks the junction between the North American and Pacific plates.
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Hotspots e.g- Island chains such as Samoa + Hawaii
Magma through the mantle erupts through the crust creating volcanoes which often rise to the ocean surface to form islands, as the plate moves, new islands form.
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An earthquake is a violent shaking of the crust, they are caused by the sudden release of enormous stresses and lead to the crust snapping.
The point at which the snapping occurs is called the focus and is below the surface of the earth and may be many km deep. On the ground surface immediately above the focus is called the epicentre and this is where the greatest damage generally occurs
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Mercalli scale - measures the intensity of an earthquake, determined by the effects of the earthquake on humans, buildings and the local landscape
It is classified into 12 grades, 1-detected by seismograph, 7-general alarm, walls show signs of cracking, 12-total destruction. Only useful in places with people as it is an arbitrary set of definitions based on what people think.
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The Richter scale - designed to allow easier comparison of earthquake magnitudes.
Recorded on Seismographs (instruments used to measure vibrations ). Each whole number represents 10 fold increase in power e.g mag. 7 is 10X more powerful than mag. 6
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Card 2

Front

No new crust is created or destroyed + no landforms form. But can cause violent earthquakes. E.g- the San Andreas Fault in California marks the junction between the North American and Pacific plates.

Back

Conservative/ transform boundaries - where plates move alongside eachother.

Card 3

Front

Magma through the mantle erupts through the crust creating volcanoes which often rise to the ocean surface to form islands, as the plate moves, new islands form.

Back

Preview of the back of card 3

Card 4

Front

The point at which the snapping occurs is called the focus and is below the surface of the earth and may be many km deep. On the ground surface immediately above the focus is called the epicentre and this is where the greatest damage generally occurs

Back

Preview of the back of card 4

Card 5

Front

It is classified into 12 grades, 1-detected by seismograph, 7-general alarm, walls show signs of cracking, 12-total destruction. Only useful in places with people as it is an arbitrary set of definitions based on what people think.

Back

Preview of the back of card 5
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