Junior Certificate Geography notes on Plate Tectonics for the Irish Second Level Curriculum

1. Plate tectonics
The Restless Earth
The earths crust is made up of many Plates. These plates float on the Magma. Magma
constantly moves, so as a result the plates are constantly moving. Europe and
America are moving apart from each other very slowly, this is called Continental
Drift. Plates move in three ways. They move apart, collide and slide past each
other. This movement is responsible for Fold Mountains, Earthquakes and
Volcanoes.
Folding
When plates collide they cause such pressure that one plate is forced under the other
and causes the crust to become buckled upwards, as a result Fold Mountains are

2. formed. These are the world’s highest mountains. They include, The Andes in
Chile, The Rockies in North America and The Alps in Europe.
Earthquakes
Earthquakes occur when plates slide past each other, Pressure builds and the
plates have to shake themselves free. The place where an earthquake occurs is called
the Focus.The Epicentre is the place directly above the Focus on the surface. This
is where most damage is done. Shock waves spread out from the focus. A Richter
Scale is used to measure the strength of an earthquake. A famous Fault Line is
the San Andreas Faultin California.
Volcanoes
Volcanoes are formed when plates separate or pull away from each other. As the
plates separate the hot magma under the surface rises up through what is known as

3. avent. Over time, and many eruptions, the layers of cooled down lava build up to
form acone shaped mountain known as a Volcano. The opening at the top of a
volcano is known as a crater. Famous examples of volcanoes are Mt. Etna and Mt.
Vesuvius, both are found in Italy. Volcanoes can cause great damage and loss of
life. However, they can also provide rich, fertile land, they are popular tourist
attractions and they have also formed new land in the form of islands such
as Iceland, Hawaii and Tenerife.