An '''earthquake''' is the shaking caused when [[plate tectonics|tectonic]] activity in an area causes the release of stored [[energy]] from the rock. Most commonly occurring on tectonic plate boundaries, earthquakes also occur along [[fault]]s where previous movement has occurred.
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Earthquakes are a significant natural [[hazard]] to populations living in areas prone to earthquakes and responses to the hazard vary with economic development.
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The most powerful and destructive earthquakes occur at tectonic plate boundaries like the [[San Andreas Fault]].