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An '''earthquake''' is the sudden movement of the Earth's [[tectonic plates]], resulting in shaking of the ground. This shaking can result in the damage of various structures such as buildings and further breakdown of the Earth's surface.  

An '''earthquake''' is the sudden movement of the Earth's [[tectonic plates]], resulting in shaking of the ground. This shaking can result in the damage of various structures such as buildings and further breakdown of the Earth's surface.  

The study of earthquakes is called [[seismology]].<ref name="camilla">{{cite book | last = | first = | authorlink = | coauthors = | title = Earth Science| publisher = Holt, Rinehart Winston| date = 2001| location = Austin, [[Texas]] 78746-6487| pages = | url = | doi = | id = | isbn = 0-03-055667-8}}</ref> Earthquakes are usually quite brief, but there may be many over a short time frame. The sudden release of tension in the [[tectonic plates]] sends waves of energy that travel through the Earth. [[Seismology]] studies the cause, frequency, type and size of earthquakes.

The study of earthquakes is called [[seismology]].<ref name="camilla">{{cite book | last = | first = | authorlink = | coauthors = | title = Earth Science| publisher = Holt, Rinehart Winston| date = 2001| location = Austin, [[Texas]] 78746-6487| pages = | url = | doi = | id = | isbn = 0-03-055667-8}}</ref> There can be many earthquakes over a short time frame in a small area. The sudden release of tension in the [[tectonic plates]] sends waves of energy that travel through the Earth. [[Seismology]] studies the cause, frequency, type and size of earthquakes.

There are [[large]] earthquakes and [[small]] earthquakes. Large earthquakes can take down buildings and cause death and injury. Earthquakes are measured using observations from [[seismograph]]s. The magnitude of an earthquake and the intensity of shaking is usually reported on the [[Richter scale]]. The Richter Scale was invented by Charles Francis Richter in 1935. On the scale, 2 is scarcely noticeable, and magnitude 5 (or more) causes damage over a wide area.

Earthquakes are measured using observations from [[seismograph]]s. The magnitude of an earthquake and the intensity of shaking is usually reported on the [[Richter scale]]. The Richter Scale was invented by Charles Francis Richter in 1935. On the scale, 2 is scarcely noticeable, and magnitude 5 (or more) causes damage over a wide area.

An earthquake under the [[ocean]] can cause a [[tsunami]], which can cause just as much destruction as the earthquake itself in mountainous areas. Earthquakes can also cause [[Landslide|landslides]]. Earthquakes are part of the Earth's natural [[rock cycle]].

An earthquake under the [[ocean]] can cause a [[tsunami]], which can cause just as much destruction as the earthquake itself in mountainous areas. Earthquakes can also cause [[landslide]]s. Earthquakes are part of the Earth's natural [[rock cycle]]. The impact of an earthquake can be measured by a seismometer. It detects the vibrations caused and it puts these movements on a seismograph. The strength, or magnitude, of an earthquake, is measured using the Richter scale. The Richter scale is numbered 0-9. The largest earthquake ever measured was a 9.5 on the scale a 10 has never been recorded.

The impact of an earthquake can be measured by a seismometer. It detects the vibrations caused and it puts these movements on a seismograph. The strength, or magnitude, of an earthquake, is measured using the Richter scale. The Richter scale is numbered 0-9. The largest earthquake ever measured was a 9.5 on the scale a 10 has never been recorded.

Scientists cannot predict an earthquake before it happens. But we do know where earthquakes might happen in the future, like close to [[fault (geology)|fault lines]].An earthquake under the ocean can cause a tsunami, this can cause just as much destruction as the earthquake itself.

Scientists cannot predict an earthquake before it happens. But we do know where earthquakes might happen in the future, like close to [[fault (geology)|fault lines]]. An earthquake under the ocean can cause a tsunami, this can cause just as much destruction as the earthquake itself.

== History ==

== History ==

1. Volcanic Earthquakes : Earthquakes which are caused by volcanic eruptions are quite devastating. However, these are confined to areas of active volcanoes.

1. Volcanic Earthquakes : Earthquakes which are caused by volcanic eruptions are quite devastating. However, these are confined to areas of active volcanoes.

2. Collapse Earthquakes : In areas of intense mining activity, often the roofs of underground mines collapse and minor tremors take place. These are called collapse earthquakes.

2. Collapse Earthquakes : In areas of intense mining activity, often the roofs of underground mines collapse and minor tremors take place. These are called collapse earthquakes.

== Earthquake fault types ==

== Earthquake fault types ==

Most earthquakes form part of a sequence, related to each other in terms of location and time.<ref name=WAAFEC>{{Cite web|url=https://earthquake.usgs.gov/eqcenter/step/explain.php|title=What are aftershocks, foreshocks, and earthquake clusters?}}</ref> Most earthquake clusters consist of small tremors which cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.<ref>{{cite web|url=https://earthquake.usgs.gov/research/parkfield/repeat.php|title=Repeating earthquakes|publisher=[[United States Geological Survey]]|date=January 29, 2009|accessdate=May 11, 2009}}</ref>

Most earthquakes form part of a sequence, related to each other in terms of location and time.<ref name=WAAFEC>{{Cite web|url=https://earthquake.usgs.gov/eqcenter/step/explain.php|title=What are aftershocks, foreshocks, and earthquake clusters?}}</ref> Most earthquake clusters consist of small tremors which cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.<ref>{{cite web|url=https://earthquake.usgs.gov/research/parkfield/repeat.php|title=Repeating earthquakes|publisher=[[United States Geological Survey]]|date=January 29, 2009|accessdate=May 11, 2009}}</ref>

A '''[[foreshock]]''' is an earthquake that occurs before a larger earthquake, called the mainshock.

A '''foreshock''' is an earthquake that occurs before a larger earthquake, called the mainshock.

An '''[[aftershock]]''' is an earthquake that occurs after a previous earthquake, the mainshock. An [[aftershock]] is in the same region of the main shock but always of a smaller magnitude. Aftershocks are formed as the crust adjusts to the effects of the main shock.<ref name=WAAFEC/>

An '''aftershock''' is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. Aftershocks are formed as the crust adjusts to the effects of the main shock.<ref name=WAAFEC/>

'''Earthquake swarms''' are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notably higher magnitudes than the other. An example of an earthquake swarm is the 2004 activity at [[Yellowstone National Park]].<ref>{{Cite web|url=http://volcanoes.usgs.gov/yvo/2004/Apr04Swarm.html|title=Earthquake swarms at Yellowstone|publisher=USGS|accessdate=2008-09-15}}</ref>

'''Earthquake swarms''' are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notably higher magnitudes than the other. An example of an earthquake swarm is the 2004 activity at [[Yellowstone National Park]].<ref>{{Cite web|url=http://volcanoes.usgs.gov/yvo/2004/Apr04Swarm.html|title=Earthquake swarms at Yellowstone|publisher=USGS|accessdate=2008-09-15}}</ref>