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Volcanoes
* There are 2 (main) kinds of
Volcanoes
1. Steep sloped with violent
(explosive) eruptions
2. Gentle sloped with
voluminous lava flows
Mount Fuji,
Japan
Steep Sloped Violent/Explosive
• Composite Cone, Stratovolcano
– Large, nearly symmetrical formed from layers of both lava and
pyroclastic materials. Gas rich magma of andesitic composition,
Dangerous, viscous lava flows, mostly located in the “Ring of Fire”.
• Mt. Fuji, Mt. St. Helens
• Cinder Cone
– Composed of loose pyroclastic material and usually form from a single
eruption. Short life and are usually smaller 30-300 meters.
• Paricutin
Gentle Sloped voluminous lava flows
• Shield volcano –
broad, slightly
dome-shaped. Most
have grown from
the deep-ocean
floor to form
islands. Form from
the accumulation of
fluid basaltic lavas
• Hawaiian islands,
Kilauea, Iceland
Factors that determine volcanic
eruption type
a. Amount of
dissolved
gases in the
magma
b. Temperature
of the magma
c. Composition
of the magma