dynamic planet - plate tectonics

Landforms created by the movement of tectonic plates 

tectonic plates move in a number of different directions. The type of direction where the plates meet translates into a particular hazard.

Sea floor spreading takes place at plate boundaries under the oceans. This continuous input of magma forms a mid-ocean ridge eg the mid atlantic ridge. On land, a rift valley forms. paleomagnetism can be used to date the age of the new tectonic crust.

Alongside convection cells in the mantle, gravity also plays a large part in the movement of tectonic plates. At destructive boundaries, gravity pulls the oceanic crust downwards at the site of subduction.

At constructive margins, magma is simply 'gap filling' where tectonic plates are moving apart, rather than being driving force that is causing the plates to move away from each other.

key terms

Focus - The point inside the crust where the pressure is released is called the focus.

Epicentre - The point on the earth's surface above the focus is called the epicentre.

Seismic wave - A wave of energy generated by an earthquake.

Benioff zone - Benioff zones are dipping, roughly planr zones of increased earthquake activity.

Mercalli scale - A twelve-point scale for expressing the local intensity of an earthquake.

Effusive eruptions - A type of volcanic eruption in which…