Final answer:
An earthquake is a trembling or shaking of the earth that is volcanic or seismic in origin. It occurs when there is a sudden release of energy in the Earth's crust, causing the ground to shake.
Step-by-step explanation:
An earthquake is best described as a trembling or shaking of the earth that is volcanic or seismic in origin. It occurs when there is a sudden release of energy in the Earth's crust, which causes the ground to shake. Earthquakes can be caused by volcanic activity or tectonic plates shifting.
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