5.15.1VolcanoesVolcanoes

volcanovolcano - a mountain that forms in - a mountain that forms in Earth’s crust when molten material, or Earth’s crust when molten material, or magma, reaches the surfacemagma, reaches the surface

magmamagma – a molten mixture of rock- – a molten mixture of rock-forming substances, gases, and water forming substances, gases, and water from the mantle / asthenospherefrom the mantle / asthenosphere

lavalava – when magma reaches the surface – when magma reaches the surface

Ring of FireRing of Fire – many volcanoes in one major – many volcanoes in one major belt around the Pacific Oceanbelt around the Pacific Ocean

Ring of Fire – Pacific OceanRing of Fire – Pacific Ocean

NorthAmerica

SouthAmerica

Pacific Ocean

Asia

Australia

What is a volcanic eruption?What is a volcanic eruption? when magma is pushing up through the when magma is pushing up through the

cracks of the crustcracks of the crust

What causes a volcanic eruption?What causes a volcanic eruption? pressurepressure

What happens to the habitat What happens to the habitat (environment) immediately after an (environment) immediately after an eruption?eruption?

It is destroyed. It dies. It is burnt.It is destroyed. It dies. It is burnt.

What happens to the habitat 2-3 years What happens to the habitat 2-3 years after an eruption?after an eruption?

It regrows.It regrows.

Mt. St. Helens, WashingtonMt. St. Helens, Washingtonerupted in 1980erupted in 1980

Mt. St. Helens, WashingtonMt. St. Helens, Washington19821982

How and where are volcanoes created?How and where are volcanoes created? At subduction zones where magma is At subduction zones where magma is

pushed up to the surfacepushed up to the surface At divergent boundaries where magma is At divergent boundaries where magma is

pushed up causing sea-floor spreadingpushed up causing sea-floor spreading At hot spots where magma randomly At hot spots where magma randomly

comes up in the middle of a plate comes up in the middle of a plate (Hawaii)(Hawaii)

““Ring of Fire” – located along the pacific Ring of Fire” – located along the pacific ocean has the most volcanoes in the ocean has the most volcanoes in the worldworld

island arcisland arc – a string of island created due – a string of island created due to plate movementto plate movement

hot spothot spot – an area where molten material – an area where molten material rises up through the crust no where near rises up through the crust no where near a plate boundarya plate boundary

Hawaii is an island arc under a hot spot.Hawaii is an island arc under a hot spot.