Volcano and Earthquake Vocabulary

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magma

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Molten rock that is underground or under the earth's surface.

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lava

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Molten rock that has broken through the Earth's surface or is on the surface.

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Shield volcano

Back

Large volcanoes with gentle slopes that erupt regularly, but rarely violently.

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Cinder cone volcano

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Smaller volcanoes with steep sides made from fragments of rock and lava that are ejected during eruptions and fall around the crater.

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Composite volcano

Back

Large volcanoes made from a combination of gentler lava flows and hot rock and lava explosions.

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pyroclastic material

Back

Hot gas, liquid magma, and solid rock that are ejected explosively during a volcanic eruption.

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caldera

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The circular depression in a volcano caused by the collapse of the magma chamber after an eruption.

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Seismology

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The study of earthquakes.

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Seismograph

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An instrument that records seismic waves.

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Seismogram

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The record of motion produced by a seismograph.