The earth’s crust is divided into tectonic plates, of which there are three types.
Constructive Plate Margin
Iceland sits on top of two tectonic plates at a constructive plate margin. At constructive margins the two plates are moving apart- like the North American and Eurasian plates in Iceland. This allows magma from the mantle to rise up to the Earth’s surface and make new crust. This is happening under the Atlantic Ocean along the Mid-Atlantic ridge.
The plate movement at the constructive margins can cause volcanic eruptions, like the Eyjafjallajokull in Iceland. Earthquakes can also be caused by the friction of the plates as they move over the mantle.
The crust on either side of a constructive plate margin often has big cracks or faults in it- caused by the massive pressure of the moving plates.
Destructive Plate Margin
At destructive plate margins, an oceanic plate and a continental plate collide.…