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Ch. 18
Vocabulary
Term | Definition |
---|---|
volcanism | describes all the processes associated with the discharge of magma, hot water, and steam. |
hot spot | unusually hot area in Earth's mantle where high-temperature plumes of mantle material rise toward the surface. |
flood basalt | potentially devastating natural occurrence in which water spills over the sides of a stream's banks onto adjacent land areas. |
fissure | are long cracks in Earth. |
conduit | a tubelike structure that allows lava to reach the surface. |
vent | opening in Earth's crust through which lava erupts and flows out onto the surface. |
crater | bowl-shape depression that forms around the central vent at the summit of a volcano. |
caldera | large crater, up to 50 km in diameter, that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption. |
shield volcano | broad volcano with gently sloping sides built by nonexplosive eruptions of basaltic lava that accumulates in layers. |
cinder cone | steep-sided, generally small volcano that is built by the accumulation of tephra around the vent. |
composite volcano | generally come-shaped hen concave slopes; built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers. |