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{{complex|date=November 2019}}

{{complex|date=November 2019}}

[[File:Sanfranciscoearthquake1906.jpg|thumb|250px|Damage from the [[San Francisco]], [[California]] earthquake, sometime in 1906.]]

[[File:Sanfranciscoearthquake1906.jpg|thumb|250px|

[[San Francisco]], [[California]] earthquake, sometime in 1960]]

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 or trembling of the Earth's [[tectonic plates]], that creates the shakes of the ground. This shaking can destroy buildings and break the Earth's surface. Sudden shake under water is called tsunami.

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.

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

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 watching from [[seismograph]]s. The magnitude of an earthquake and the power 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) creates 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]]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.

An earthquake under the [[ocean]] can destruction as the earthquake itself in mountainous areas. Earthquakes can also create [[landslide]]s. Earthquakes are part of the Earth's natural [[rock cycle]]. The affect of an earthquake can be measured by a seismometer. It detects the shakes 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 create a tsunami, this can create just as much destruction as the earthquake itself.

 

 

The second part is the alpide. It is the seismic activities from [[Sumatra]], [[Himalayas|Himalayan]], europan to outer atlantic.  

== History ==

== History ==

Earthquakes sometimes hit cities and kill hundreds or thousands of people. Most earthquakes happen along the [[Pacific Ring of Fire]] but the biggest ones mostly happen in other places. [[Tectonically]] active places are places where earthquakes or [[volcanic eruption]]s are quite frequent.

Earthquakes sometimes hit cities and kill hundreds or thousands of people. Most earthquakes happen along the [[Pacific Ring of Fire]] but the biggest ones mostly happen in other places. [[Tectonics|Tectonically]] active places are places where earthquakes or [[volcanic eruption]]s are quite repeated.

== Causes of an earthquake ==

== Causes of an earthquake ==

{{main|plate tectonics}}

{{main|plate tectonics}}

Earthquakes are caused by tectonic movements in the Earth's crust. The main cause is when [[Plate tectonics|tectonic plates]] ride one over the other, causing [[orogeny]] (mountain building), and severe earthquakes.

Earthquakes are caused by tectonic movements in the Earth's crust. The main cause is when [[Plate tectonics|tectonic plates]] ride one over the other, causing [[orogeny]] (mountain building), and severe earthquakes.<ref>{{Cite web|title=Science of Earthquakes Seismic Zones|url=https://www.prfire.co.uk/press_releases/science-of-earthquakes-seismic-zones|access-date=2021-07-09|website=PR Fire|language=en-GB}}</ref>

The boundaries between moving plates form the largest [[Fault (geology)|fault]] surfaces on Earth. When they stick, motion between the plates leads to increasing stress. This continues until the stress rises and breaks, suddenly allowing sliding over the locked portion of the fault. This releases the [[Potential energy|stored energy]] as [[shock wave]]<nowiki/>s. The [[San Andreas Fault|San Andreas fault]] in [[San Francisco]], and [[Great Rift Valley|Rift valley]] fault in [[Africa]] are faults like this.

The boundaries between moving plates form the largest [[Fault (geology)|fault]] surfaces on Earth. When they stick, motion between the plates leads to increasing stress. This continues until the stress rises and breaks, suddenly allowing sliding over the locked portion of the fault. This releases the [[Potential energy|stored energy]] as [[shock wave]]<nowiki/>s. The [[San Andreas Fault|San Andreas fault]] in [[San Francisco]], and [[Great Rift Valley|Rift valley]] fault in [[Africa]] are faults like this.

== Earthquake clusters ==

== Earthquake clusters ==

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|access-date=May 11, 2009}}</ref>

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

A '''foreshock''' is an earthquake that happens 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 happens after a previous earthquake, the mainshock. An aftershock is in the same place 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|access-date=2008-09-15}}</ref>

Sometimes a series of earthquakes occur in a sort of '''earthquake storm''', where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern occurred in the North [[Anatolia]]n fault in [[Turkey]] in the 20th century.<ref>{{cite journal | title = Poseidon’s horses: plate tectonics and earthquake storms in the late Bronze Age Aegean and Eastern Mediterranean | journal = Journal of Archaeological Science | year = 2000 | author = Amos Nur | issn = 0305-4403 | volume = 27 | pages = 43–63 | url = http://water.stanford.edu/nur/EndBronzeage.pdf | doi = 10.1006/jasc.1999.0431 }}</ref><ref>{{cite web | url = http://www.bbc.co.uk/science/horizon/2003/earthquakestorms.shtml | title = Earthquake storms | work = Horizon (BBCtv series) | date = 1 April 2003 | accessdate = 2007-05-02 }}</ref>

Sometimes a series of earthquakes happen in a sort of '''earthquake storm''', where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms happen over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern happened in the North [[Anatolia]]n fault in [[Turkey]] in the 20th century.<ref>{{cite journal | title = Poseidon’s horses: plate tectonics and earthquake storms in the late Bronze Age Aegean and Eastern Mediterranean | journal = Journal of Archaeological Science | year = 2000 | author = Amos Nur | issn = 0305-4403 | volume = 27 | pages = 43–63 | url = http://water.stanford.edu/nur/EndBronzeage.pdf | doi = 10.1006/jasc.1999.0431 | access-date = 2010-06-17 | archive-date = 2009-03-25 | archive-url = https://web.archive.org/web/20090325050459/http://water.stanford.edu/nur/EndBronzeage.pdf | url-status = dead }}</ref><ref>{{cite web | url = http://www.bbc.co.uk/science/horizon/2003/earthquakestorms.shtml | title = Earthquake storms | work = Horizon (BBCtv series) | date = 1 April 2003 | access-date = 2007-05-02 }}</ref>

== Tsunami ==

== Tsunami ==

'''[[Tsunami]]''' or a [[chain]] of fast moving [[wave]]s in the [[ocean]] caused by powerful earthquakes is a very serious challenge for people's safety and for [[earthquake engineering]]. Those waves can [[inundate]] coastal areas, destroy [[house]]s and even swipe away whole [[town]]s.<ref>[https://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0001xgp.php USGS Poster of the Near the East Coast of Honshu, Japan Earthquake of 11 March 2011 - Magnitude 8.9]</ref> This is a danger for the whole mankind.

'''[[Tsunami]]''' or a [[chain]] of fast moving [[wave]]s in the [[ocean]] caused by powerful earthquakes is a very serious challenge for people's safety and for [[earthquake engineering]]. Those waves can [[inundate]] coastal areas, destroy [[house]]s and even swipe away whole [[town]]s.<ref>[https://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0001xgp.php USGS Poster of the Near the East Coast of Honshu, Japan Earthquake of 11 March 2011 - Magnitude 8.9]</ref> This is a danger for the whole mankind.

Unfortunately, tsunamis can not be prevented. However, there are [[Tsunami warning system|warning systems]]<ref>[http://ptwc.weather.gov Pacific Tsunamy Warning Center]</ref> which may warn the [[population]] before the big waves reach the [[land]] to let them enough time to rush to safety.we aware of this tsunami

Unfortunately, tsunamis cannot be prevented. However, there are [[Tsunami warning system|warning systems]]<ref>{{Cite web |url=http://ptwc.weather.gov/ |title=Pacific Tsunamy Warning Center |access-date=2021-01-18 |archive-date=2011-03-13 |archive-url=https://www.webcitation.org/5x8nAhhwJ?url=http://ptwc.weather.gov/ |url-status=dead }}</ref> which may warn the [[population]] before the big waves reach the [[land]] to let them enough time to rush to safety.

== Earthquake-proofing ==

== Earthquake-proofing ==

{{main|Earthquake engineering}}

{{main|Earthquake engineering}}

Earthquake-proof buildings are constructed to withstand the destructive force of an earthquake. This depends upon its type of construction, shape, [[mass]] distribution, and [[wikt:rigid|rigidity]]. Different combinations are used. Square, rectangular, and shell-shaped buildings can withstand earthquakes better than [[skyscraper]]s. To reduce stress, a building's ground floor can be supported by extremely rigid, hollow columns, while the rest of the building is supported by flexible columns inside the hollow columns. Another method is to use rollers or rubber pads to separate the base columns from the ground, allowing the columns to shake parallel to each other during an earthquake.

Earthquake-proof buildings are constructed to withstand the destructive force of an earthquake. This depends upon its type of construction, shape, [[mass]] distribution, and [[wikt:rigid|rigidity]]. Different combinations are used. Square, rectangular, and shell-shaped buildings can withstand earthquakes better than [[skyscraper]]s. To reduce stress, a building's ground floor can be supported by extremely rigid, empty columns, while the rest of the building is supported by flexible columns inside the empty columns. Another method is to use rollers or rubber pads to separate the base columns from the ground, allowing the columns to shake parallel to each other during an earthquake.

To help prevent a roof from collapsing, builders make the roof out of light-weight materials. Outdoor walls are made with stronger and more reinforced materials such as steel or [[reinforced concrete]]. During an earthquake flexible windows may help hold the windows together so they don’t break.

To help prevent a roof from collapsing, builders make the roof out of light-weight materials. Outdoor walls are made with stronger and more reinforced materials such as steel or [[reinforced concrete]]. During an earthquake, flexible windows may help hold the windows together so they don’t break.

== Sources ==

== Sources ==

{{Commons category|Earthquakes}}

{{Commons category|Earthquakes}}

* [https://www.pbs.org/newshour/science/earthquake/ PBS NewsHour - Predicting Earthquakes]

* [https://www.pbs.org/newshour/science/earthquake/ PBS NewsHour - Predicting Earthquakes]

* [http://neic.usgs.gov/neis/eqlists/10maps_world.html USGS – Largest earthquakes in the world since 1900]

* [http://neic.usgs.gov/neis/eqlists/10maps_world.html USGS – Largest earthquakes in the world since 1900] {{Webarchive|url=https://web.archive.org/web/20090303054812/http://neic.usgs.gov/neis/eqlists/10maps_world.html |date=2009-03-03 }}

* [http://www.armageddononline.org/earthquake.php The Destruction of Earthquakes] - a list of the worst earthquakes ever recorded

* [http://www.armageddononline.org/earthquake.php The Destruction of Earthquakes] {{Webarchive|url=https://web.archive.org/web/20090208004752/http://www.armageddononline.org/earthquake.php |date=2009-02-08 }} - a list of the worst earthquakes ever recorded

* [https://earthquake.usgs.gov/eqcenter/recenteqsww/ Recent Quakes WorldWide]

* [https://earthquake.usgs.gov/eqcenter/recenteqsww/ Recent Quakes WorldWide]

* [http://en.citizendium.org/wiki/Earthquake Earthquake] Citizendium

* [http://en.citizendium.org/wiki/Earthquake Earthquake] Citizendium