Volcanoes

Volcanoes

* There are 2 (main) kinds of Volcanoes

1.Steep sloped with violent (explosive) eruptions2.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