Difference between revisions of "Earthquake"
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Earthquakes are a significant natural [[hazard]] to populations living in areas prone to them, and emergency responses to the hazard vary with economic development. The most powerful and destructive earthquakes occur at tectonic plate boundaries like the [[San Andreas Fault]]. | Earthquakes are a significant natural [[hazard]] to populations living in areas prone to them, and emergency responses to the hazard vary with economic development. The most powerful and destructive earthquakes occur at tectonic plate boundaries like the [[San Andreas Fault]]. | ||
| − | The severity of earthquakes is measured using the [[Moment Magnitude scale]], which replaced the [[Richter scale]] | + | The severity of earthquakes is measured using the [[Moment Magnitude scale]], which replaced the [[Richter scale]] in the 1970s. The largest quake ever recorded had a magnitude of 9.5; it struck Chile in 1960<ref>http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php</ref>. Technically the Moment Magnitude scale only measures the absolute magnitiude; the [[Mercalli scale]] is used to measure the felt magnitude - essentially how much the ground shakes over the epicentre of the quake.. |
Revision as of 02:58, September 22, 2011
An earthquake is when the Earth shakes, caused by tectonic activity in an area after the release of stored energy from the rock. Earthquakes most commonly occur on tectonic plate boundaries, and also occur along faults where previous movement has occurred. There are currently 500,000 detectable earthquakes in the world each year.
Earthquakes are a significant natural hazard to populations living in areas prone to them, and emergency responses to the hazard vary with economic development. The most powerful and destructive earthquakes occur at tectonic plate boundaries like the San Andreas Fault.
The severity of earthquakes is measured using the Moment Magnitude scale, which replaced the Richter scale in the 1970s. The largest quake ever recorded had a magnitude of 9.5; it struck Chile in 1960[1]. Technically the Moment Magnitude scale only measures the absolute magnitiude; the Mercalli scale is used to measure the felt magnitude - essentially how much the ground shakes over the epicentre of the quake..
See also
External links
- Historical Earthquakes in China
- Latest Earthquakes in the World - Past 7 days.
- Latest Earthquakes in the North America Region.