volcanoes 8 th grade physical science. how are volcanoes formed? o gases force magma, melted rock in...
TRANSCRIPT
How are Volcanoes Formed?
O Gases force magma, melted rock in the Earth to rise. If magma breaks through the Earth’s surface, a volcano is formed.
Shield VolcanoO They release relatively fast-moving
less gassy lava, and tend to have less explosive eruptions than other types of volcanoes.
O People often walk fairly close to these erupting volcanoes.
O They usually form large, broad volcanoes.
Composite Cone Volcano
O These volcanoes have explosive eruptions as a result of more gassy magma.
O They are formed from layers of lava and ash.
O Composite Cones are also known as stratovolcanoes.
Cinder Cone VolcanoO These are the smallest and most
common volcanoesO They are formed from explosive
eruptions that shoot small pieces of magma and ash into the air.
O The magma then cools and hardens as it falls back to the Earth, forming a cinder cone.
O In many cases, cinder cones form on the sides of a larger volcano.
Active VolcanoO Active volcanoes is one that has
erupted since the last ice age approximately in the past 10,000 years.
Dormant VolcanoO Dormant volcanoes would then be
one that hasn’t erupted in the past 10,000 years, but it is expected to erupt again.