An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves.
Earthquakes are recorded with a seismometer, also known as a seismograph.
At the Earth's surface, earthquakes manifest themselves by a shaking and sometimes displacement of the ground.
When a large earthquake epicentre is located offshore, it can cause a tsunami.
The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
The word earthquake is used to describe any seismic event - whether a natural phenomenon or an event caused by humans - that generates seismic waves.
Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments.
An earthquake's point of initial rupture is called its focus or hypocentre.
The term epicentre means the point at ground level directly above this.
Intensity of shaking is measured on the modified Mercalli scale.
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