Destructive plate margin

At destructive plate margins, subduction zones and ocean trenches will be formed.

Deconstructive boundary

At a destructive boundary the plates are moving towards each other.

This usually involves a continental plate and an oceanic plate.

The oceanic plate is denser than the continental plate. As they move together, the oceanic plate is forced underneath the continental plate.

The point at which this happens is called the subduction zone.

When the oceanic plate is forced below the continental plate it melts to form magma and earthquakes are triggered.

As the plate is forced down, there will be deep gap under the sea which is known as an ocean trench.

The magma collects to form a magma chamber.

This magma then rises up through cracks in the continental crust.

As pressure builds up, a volcanic eruption may occur causing composite cone volcanoes (e.g. Nevado del Ruiz in Colombia).

A major example of this plate movement is along the coastline of South America (at the Nazca and South American plate boundary).