Earthquake

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Earthquake

What is an earthquake?

An earthquake is a shaking of the ground caused by the sudden breaking and movement of large sections (tectonic plates) of the earth's rocky outermost crust. The edges of the tectonic plates are marked by faults (or fractures). Most earthquakes occur along the fault lines when the plates slide past each other or collide against each other.

What causes an earthquake?

There are two main causes of earthquakes.

Firstly, they can be linked to explosive volcanic eruptions; they are in fact very common in areas of volcanic activity where they either proceed or accompany eruptions.

Secondly, they can be triggered by Tectonic activity associated with plate margins and faults. The majority of earthquakes worldwide are of this type.

Terminology

An earthquake can be likened to the effect observed when a stone is thrown into water. After the stone hits the water a series of concentric waves will move outwards from the centre. The same events occur in an earthquake. There is a sudden movement within the crust or mantle, and concentric shock waves move out from that point. Geologists and Geographers call the origin of the earthquake