Composite Volcanoes are also called Stratovolcanoes or Teapot volcanoes. They are called teapots because they steam, whistle, and blow their tops a lot. They are called composite or strato because they are layered or made up of different things. Layered because they are composed of short lava flows (typically Andesite in composition), ash falls, pyroclastic flows, and debris avalanche/flow deposits. The percentage of each varies from volcano to volcano. This is what makes them so dangerous- one never knows whether or not they will flow or blow their tops.
These volcanoes are steep sided (up to 30 degrees) and typically have circular openings at their tops- they form the beautiful, majestic-looking mountains such as Agung Volcano in Indonesia above.
The magma or lava that forms these volcanoes is more viscous or stickier than that forming shield volcanoes.
Composite volcanoes range from Andesite to Rhyolite in composition and tend to form at subduction zones or within back arc basins. They thus form Island Arcs (Unzen, Pelee, Merapi, Krakatoa, Pinatubo), or continental mountains (St. Helens, Rainer, Galeras).
| Hazards | Deposits | Eruptions | Precambrian |
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