Types of Volcanoes

• Occurs where an elongated crack in the crust allows lava to spill out over a large area. 
• Typically found around spreading ridges where tension pulls the crust apart. 
• Existing tapography was drowed in a vast lake of basaltic lava. 

• Rock type: Basaltic
• Location: Early constructive margins
• Eruption: Gentle persistent.

• Made of basaltic rock and form gently sloping cones from layers of less viscous lava. 
• They are much bigger.
• An entire structure extend 10, 999m from the ocean floor. 

• Rock type: Basaltic
• Location: Hot spots / Oceanic crust meets oceanic crust.
• Eruption: Gentle, predictable

• Common type found on land.
• Created by layers of ash from initial explosive phases of eruption and subsequent layers of lava from main eruption phases. 
• Rock type: Andesitic
• Location: Destructive margins.
• Eruption: Explosive, Unpredictable margins

Acid/Dome Volcano

• Steep sided volcanoes formed from very viscous lava. 
• Lava can't travel far - builds up convex cone shaped volcanoes.
• Lava may solidify in the vent and be revealed later by erosion.
  • Rock type: Rhyolitic
  • Location: Continental crust
  • Eruption: Explosive, Unpredictable

• Form when gases that have built up beneath a blocked volcanic vent result in a catastrophoc eruption that destroys the volcano summit. 
• It leaves an enormous crater where later eruption may form smaller cones.

• Rock type: Andesitic
• Location: Destructive margins.
• Eruption: Very explosive, Unpredictable