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Physical processes at plate margins 2.2
Constructive Plate Boundary, – This is when two plates move apart from each other.
Describe the movement of a Constructive Plate Boundary and the effects (4 Marks)
‘The two plates move apart and magma forces its way to the surface. As it breaks the crust, it can cause mild earthquake. The magma is very hot and fluid which allows the lava to flow a long way before cooling. This results in shield volcanoes.’
Destructive Plate Boundary, – This is when two plates move together. (these plates are the oceanic and continental plates)
Describe the movement of a Destructive Plate Boundary and the effects. (4 Marks)
‘A destructive plate boundary is when two plates move together. The dense oceanic plate is subducted beneath the less continental plate. Then friction causes strong earthquakes. This leads the sinking oceanic plate to create magma. This results in a steep-sided composite volcano which erupts violently. However, when two continental plates meet, there is no subduction. This means that no magma to from volcanoes. But the crust crumples and lifts to form fold mountains. This can cause powerful earthquakes to be triggered.’
Conservative Plate Boundary, – This is when two plates move past each at different rates.
Describe the movement of a Conservative Plate Boundary and the effects. (3 Marks)
‘Two plates move past each other at different rates. Friction between the plates build stress and trigger earthquakes when they slip. There are no volcanoes because there is no magma.’
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