An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates waves of seismic activity. The seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. This is calculated by a recording device called a seismograph, using a magnitude scale. The best known magnitude scale is called the Richter Scale. It measures from 1 which is barely noticed to 12 which is a catastrophic disaster.
Another scale to describe earthquakes is the modified mercalli (MM). It rates the amount of shaking felt at a particular place and damage caused, (or intensity) and uses Roman numerals. On this scale I = detectable by instruments only and XII = Total Destruction.
On the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity.
In its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests.
An earthquake's point of initial rupture is called its focus or hypocenter. The epicentre is the point at ground level directly above the hypocenter.
Another scale to describe earthquakes is the modified mercalli (MM). It rates the amount of shaking felt at a particular place and damage caused, (or intensity) and uses Roman numerals. On this scale I = detectable by instruments only and XII = Total Destruction.
On the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity.
In its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests.
An earthquake's point of initial rupture is called its focus or hypocenter. The epicentre is the point at ground level directly above the hypocenter.