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Back to category: Science Limited version - please login or register to view the entire paper. Earthquakes Earthquakes occur throughout the world but the vast majority of them develop along narrow belts. These belts are tens to thousands of kilometres long and mark the boundaries on the Earth's surface. The belts are considered very active geological wise. Earthquakes occur when rocks rupture under the pressure created by continuos movement and collision of thin jigsaw-like tectonic plates found under the Earth's surface. Seismic waves(vibrations) are then created and proceed outwards in all directions at up to 14 kilometres per second. The fastest waves would only take up to 20 minutes to reach the other side of the Earth. The focus point is the section of Earth directly above the earthquake – also known as the epicentre. The focus point can be as deep as 700 kilometres deep. Faulting causes a release of energy because stored up stress is unexpectedly transformed to motion causing an earthquake. The waves disfigure the rocks they pass through but once the waves hav... Posted by: Margaret Rowden Limited version - please login or register to view the entire paper. |
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