Related topics: quake · earthquake

On the front lines in Kilauea

In the early spring, volcanologists monitoring the ground around Kilauea, the most active volcano on the island of Hawai'i, noticed a significant increase in seismicity, a sign of an impending eruption. Meanwhile, in Palisades, ...

Mount Etna eruption causes airspace closure

The Mount Etna volcano erupted on Monday, spewing ash as several minor earthquakes hit the region, and prompting a partial closure of the Sicilian airspace around the mountain.

'Majority rules' when looking for earthquakes, explosions

A dormant volcano in Antarctica helped researchers at Sandia National Laboratories improve sensor data readings to better detect earthquakes and explosions and tune out everyday sounds such as traffic and footsteps.

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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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