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Boundaries Types

Transform

• Two plates slide past each other

• As they slide, earthquakes often occur

• Examples: California’s San Andreas Fault

Divergent

• When two plates spread away from each other forming new crust

• Causes earthquakes and volcanoes

• Usually undersea• Example: Iceland

Convergent- Ocean-Ocean• When two ocean

plates meet• As the denser plate

slides underneath the other, the plate melts to magma and rises

• Magma reaches ocean floor and slowly rises to form volcanic island arcs

• Earthquakes can occur

• Example: Ring of Fire

Convergent – Ocean-Continent• When an ocean

plates slides under a continent plate

• Forms volcanoes and earthquakes like an ocean-ocean boundary

• Examples: Western South America (Andes), Mt. St. Helens, Washington

Convergent Continent-Continent• Occurs when two

continent plates meet• Since similar

densities, they do not slide easily underneath in to mantle

• The force of the collision pushes up mountains

• Earthquakes are common

• Example: The Himalayas