The rare, powerful 5.8-magnitude earthquake that shook the east coast United States on Tuesday, August 23, 2011, caused minimal damage but surprised and unnerved millions of people. The quake occurred near Mineral, Virginia, about 100 miles southwest of Washington, D.C., and was recorded all along the Appalachians, from Georgia to New England.
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Current instrumentation shows that around 500,000 total earthquakes occur each year. Of those, around 100,000 are large enough to be felt by people.
Quakes are usually caused by a rupture in geological faults, but they can also be caused by events, such as volcanic activity, landslides, mine blasts and nuclear tests.
Minor earthquakes occur nearly constantly around the world in places like California and Alaska, but earthquakes can occur almost anywhere. They can last only a few seconds or may continue for several minutes. And they can occur at any time of the day or night, and at any time of the year.
Scientists have learned a lot about earthquakes over the years, but there is still much that we don't know, like how to accurately forecast them.
WorldWideScience allows users to quickly search -- at no cost -- over 400 million pages of important science information, across every inhabited continent, with a single query, and to simultaneously explore a multitude of nationally-sponsored science sources not readily available through any other search engine. And the site reduces language barriers by providing translations across ten languages.
WorldWideScience.org was developed and is maintained by the Office of Scientific and Technical Information (OSTI), a division of the Office of Science within the Energy Department.