Volcano

· The place in the Earth surface through which magma and other materials and other materials reach the surface

- Magma is the rock that exists as a hot liquid

§ Due to tremendous pressure and extreme temperature

§ When it reaches surface called lava

Volcano Terms

Vent

· The opening through which lava erupts

Crater

· The funnel-shaped pit at the top of a volcanic cone

Calderas

· A large crater, resulting from the collapse of crater walls

How Volcanoes Form

· Deep within the Earth the magma works its way through cracks in solid rock

· Usually form from convergent boundaries

Types of Volcanoes

Cinder Cone

· Formed from explosive eruptions

· Made of cinders and rock particles

· Are not very high but have steep sides

Shield Volcanoes

· Have quiet lava flows that will flow over a large area

· After several eruptions it will form a gently sloping, dome shaped mountain

- Hawaiian Islands

Composite Volcanoes

· Built of alternating layers of rock particles and lava

· 1^st a violent eruption- ash flies out

Then a quiet eruption- lava flow

- Mt. Vesuvius in Italy

States of Volcanoes

Volcanoes can be……

· Active: still erupts continually

· Dormant: “sleeping”, has erupted in modern times

· Extinct: has not erupted in modern history

· But!!!! Volcano Activity Is Not Predictable!!!!!