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Both the opening in the Earth's crust through which molten rock, gases, and ash erupt and the landform that develops around this opening.
Volcanoes form on the overriding plate as subducting plate melts to form magma.
Example of a chain of volcanoes on an ocean/continent convergent boundary
Cascade Range of Pacific Northwest
Almost all divergent volcanism is (1)_________. Except in (2)__________.
(1) underwater. (2) iceland
Areas of volcanic activity that result from plumes of hot solid material that have risen from deep within Earth's mantle. As this rises, it melts to produce magma.
What happens when a hotspot is under land?
It erupts through cracks (called fissures) and forms flood basalts, resulting in lava plateaus.
Forms when the top of a volcano collapses after an eruption empties part of the lava chamber underneath it.
Made with basalt. Very fluid and will flow long distances before cooling. Volcanoes have a very broad, circular base with shallow slope. Largest type of volcano. Non-explosive eruptions.
Cinder Cone Volcano
Molten lava thrown into air from vent, form solid fragments that fall on ground around vent. Cone-shaped mound with oval base and steep sides. Smaller than other types, often found in groups.
3 conditions which allow solid asthenosphere to melt and form magma
1.) Decrease in pressure- divergent zones where lithosphere thinner and exert less pressure.
2.) Increase in temperature- hot spots.
3.) Increase in water in asthenosphere- subduction boundaries.
a dense, superheated cloud of gases and pyroclastic material that travels downhill at high speed.
Irregularly shaped mass of coarse-grained igneous rocks that cover at least 100 km2 and take millions of years to form. Common in interior of mountain chains.
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