Pediatrics

Nepal quake leaves children traumatised

Ten-year-old Ranju Giri wrings her hands as she describes how she cowered terrified under a bed with her younger brother when a massive earthquake rocked their home in Kathmandu.

Diseases, Conditions, Syndromes

UN chief in Haiti launches sanitation program (Update)

U.N. Secretary-General Ban Ki-moon visited rural Haiti on Monday to help launch a program to improve sanitation and fight the spread of cholera, a disease many Haitians blame U.N. peacekeepers for introducing to the impoverished ...

Psychology & Psychiatry

Japan quake shows how stress alters the brain

(HealthDay)—A small study of people who experienced the devastating 2011 earthquake in Japan shows that although traumatic events can shrink parts of the brain, some of those regions can rebound once a person's self-esteem ...

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Earthquake

An 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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