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Types of Volcano - Coggle Diagram
Types of Volcano
Acid/Dome Volcanoes
Gas rushes up through the sicky lava and blasts ash and fragments up in the sky in a huge explosion. This creates immense clouds of gas and debris several km thick.
Gas clouds and lava can also rush down the slopes - some of the volcano can be blasted away during the eruption.
Examples: Mount St Helens lava dome, Novarupta, Alaska.
Very viscous lava, relatively small, can be explosive, commonly occurs adjacent to craters of composite volcanoes.
Fissure Volcanoes
Characterised by persistent fissure eruption. Large quantities of basaltic lava build up past horizontal plains.
Examples: Laki, Iceland, Deccan Plateau, Columbia Plateau.
Very liquid lava, flows very widespread, emitted from fractures.
Shield Volcanoes
Involve more noticeable central activity than fissure volcanoes. Lava travels down the side of volcanoes, gases escape easily - occasional pyroclastic activity.
Examples: Hawaiian volcanoes, Mount Sylvania.
Runny, basaltic lava emitted from the central vent, sometimes has a collapse caldera.
Composite Volcanoes
Characterised by very powerful blasts of gas pushing ash clouds high in the sky. More violent than other types. Lava flows occur and ash covers the surrounding area.
Examples: Mount Hood, Mount Baker.
More viscous lava, explosive pyroclastic debris emitted from central vent.
Caldera
Large scale volcanic crater formed as a result of an explosive eruption which emptied the magma chamber causing the volcano sides to subside. Usually more than 2km in diameter.
Examples: 1883 eruption of Krakatoa, Indonesia left a caldera 7km wide, Yellowstone, Medicine Lake.
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