1. Plate Tectonics L.O: To know about different plate margins and what happens when they push together or move apart.

2. Plate Margin
The meeting place of one plate (plates make up the top layer of the Earth's structure) with another plate. There are four types of plate margin – destructive, constructive, collision, and conservative. A volcano may be found along two of the types of plate margin, and an earthquake may occur at all four plate margins.

4. Destructive

5. Destructive
At a destructive margin an oceanic plate moves towards (and disappears into the mantle of) a continental plate or another oceanic plate. This is the subduction zone. As it is forced downwards, pressure at the margins increases, and this can result in violent earthquakes. The heat produced by friction turns the crust into magma (liquid rock). The magma tries to rise to the surface and, if it succeeds, violent volcanic eruptions occur.

6. Destructive

7. Conservative

8. Conservative plate margins
At a conservative margin two plates try to slide past each other slowly. Quite often, the two plates stick and pressure builds up; the release of this pressure creates a severe earthquake. There are no volcanic eruptions along conservative plate margins because the crust is neither being created nor destroyed. The San Andreas Fault in California lies above the North American and Pacific plates, and is an example of a conservative plate margin.

9. Conservative

10. Constructive

11. Constructive plate margins
At a constructive margin the Earth's crust is forced apart. Magma rises and solidifies to create a new oceanic crust and forms a mid-ocean ridge. This ridge is made from igneous rock; such ridges usually form below sea level on the sea bed (an exception to this is in Iceland).

12. Constructive

13. Mid Atlantic Ridge

14. Collision

15. Collision
Two Continental crusts move together. Neither goes under the other, and they therefore buckle, or 'fold'. Over a large period of time, this creates mountains, such as the Himalayas. This may cause severe earthquakes, but not volcanoes.

17. Collision – India

18. Collision – India

19. Plate Movement