Earthquake
hideAn earthquake (also known as a tremor or temblor) 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. The moment magnitude of an earthquake is conventionally reported, or the related and mostly obsolete Richter magnitude, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.
At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.
In its most generic sense, 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 hypocenter. The term epicenter refers to the point at ground level directly above the hypocenter.
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News tagged with seismic activity
Small faults in Southeast Spain reduce earthquake risk of larger ones
Space & Earth / Earth Sciences
22 hours ago |
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A team of Spanish scientists, studying recent, active deformations in the Baetic mountain range, have shown that the activity of smaller tectonic structures close to larger faults in the south east of the ...
New way to track quakes
Space & Earth / Earth Sciences
Sep 08, 2009 |
5 / 5 (4) |
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(PhysOrg.com) -- University of Edinburgh scientists have developed a new technique to monitor movements beneath the Earth's surface.
Study reveals seismic shift in methods used to track earthquakes
Space & Earth / Earth Sciences
Sep 02, 2009 |
4 / 5 (2) |
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The team, led by scientists from the University of Edinburgh, says that the new method, which uses data collected from earthquakes, potentially allows the Earth's seismic activity to be mapped more comprehensively.
Scientists lower Alaska volcano threat level
Space & Earth / Earth Sciences
Jul 01, 2009 |
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(AP) -- Alaskans can put away their dust masks and spare air filters, for now, because Mount Redoubt seems to have cooled off since its last major eruption nearly three months ago.
Huge undersea mountain found off Indonesia: scientists
Space & Earth / Earth Sciences
May 29, 2009 |
3.9 / 5 (16) |
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A massive underwater mountain discovered off the Indonesian island of Sumatra could be a volcano with potentially catastrophic power, a scientist said Friday.
Ash falls on Anchorage as volcano keeps spewing
Space & Earth / Earth Sciences
Mar 29, 2009 |
not rated yet |
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(AP) -- Alaska's Mount Redoubt continued to erupt Saturday, sending plumes of ash tens of thousands of feet into the air that rained down on at least one Alaska town
Alaska's Mount Redoubt spews ash 50,000 feet high
Space & Earth / Earth Sciences
Mar 28, 2009 |
5 / 5 (2) |
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(AP) -- Alaska's Mount Redoubt has erupted again, spewing an ash cloud 50,000 feet up into the air.
Scientists Study Earthquake Swarm Near Maupin
Space & Earth / Earth Sciences
Dec 23, 2008 |
3.8 / 5 (8) |
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(PhysOrg.com) -- During the last two years more than 350 small earthquakes have been recorded just outside the small eastern Oregon town of Maupin and scientists are unsure what is triggering the activity.
