KEY POINTS IN THIS CHAPTER •
Volcanoes have existed since there has been crust on earth.
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There are four major volcanic structures – lava domes, cinder cones, composite, and shield volcanoes.
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Not all volcanoes emit basaltic lava, especially near subduction zones.
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Volcanoes range on a logarithmic explosivity scale from 0 to 8.
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Volcanic eruptions can involve one or more vents, gentle flows, explosive gases, and steam, depending on the different types.
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You can somewhat predict the presence of an impending volcanic eruption by measuring different things, such as gas emissions, ground deformation, sounds beneath the ground, and seismic activity.
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