Fault lines are located in many parts of the world and are closely related to the structure of the Earth.
Earthquakes
Large earthquakes are usually connected with plate boundaries. Earthquakes happen often but most are too small for us to notice. Seismometers record earth movements. An earthquake is a sudden shockwave caused by rocks being under stress from the movements of plates at plate boundaries. Eventually the stress in the rock builds up enough to deform and reach breaking point. At that point, the stored up energy is released in the form of shockwaves. The point where an earthquake starts is called the focus and the epicentre is the point on the Earth’s surface, immediately above the focus. Near the epicentre, the waves are stronger and cause more damage.
The device which measures the magnitude of the earthquake is the seismometer, a machine with a seismograph in a revolving drum. The vibrations from an earthquake are recorded by an arm, which moves up and down, with a pen at the end. These readings are measured using the open-ended Richter Scale.
Even though most earthquakes go unnoticed, some have huge effects.They can cause mass death and destruction such as the 1960 Valdivia Earthquake in Chile. This earthquake resulted in a tsunami which hit other countries far, far away such as Japan, the Philippines, New Zealand and Australia. It is regarded as the worst earthquake in history, measuring 9.6 on the Richter Scale.
Below is a video about earthquakes.
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