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.
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 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 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 Fault in California.
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 a vent. Over time, and many eruptions, the layers of cooled down lava build up to form a cone 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.
Here’s a song you may recognise that will help you remember….