At convergent boundaries, Teutonic plates move toward each other and collide. Where an oceanic plate collides with a continental plate, the oceanic plate tips down and slides beneath the continental plate forming a deep ocean trench (which is a long, narrow, deep basin.) An example of this type of movement, called subduction, occurs at the boundary between the oceanic Nazca Plate, a smaller plate, and the continental South American Plate. Where continental plates collide, they form major mountain systems such as the Himalayas.

  At divergent boundaries, plates move away from each other such as at the Mid-Atlantic Ridge. Where plates diverge molten rock rises and cools adding new material to the edges of the oceanic plates. What is happening is known as sea-floor spreading.

  At transform-fault boundaries, plates move horizontally past each other. The San Andreas Fault zone is an example of this type of boundary where the Pacific Plate on which Los Angeles sits is moving slowly northwestward relative to the North American Plate on which San Francisco sits.

  Plate tectonics, the branch of science that deals with the process by which rigid plates are moved across hot molten material, has helped to explain much in global-scale geology including the formation of mountains, and the distribution of earthquakes and volcanoes. In return, knowing about the plates can one day possibly lead to a safer future.