Earthquakes: Plate Boundaries

• Pacific Plate
• North American Plate
• South American Plate
• Nazca Plate
• Antarctic Plate
• African Plate 
• Indian Plate 
• Eurasian Plate

Two plates that are moving apart.

Example: Mid-Atlantic Ridge

• Plates move away from each other 
• Hot magma rises from beneath the ground
• New mountains form under the sea
• Mountain tops break the surface as volcanic islands
• New crust is formed at the margin from cooling magma

The movemnet can cause earthquakes.

Two plates sliding past each other.

Example: California San Andreas Fault

• Plates try to slide past each other
• Plates stick together/jam
• Huge amounts of pressure build up
• Pressure releases causing violent earthquake
• No new crust is formed

This can cause earthquakes but not volcanic activity.

Two plates moving towards each other, both continemtal crusts.

Example: Hamalayan Mountains

• Plates move towards each other
• Plates can't sink so crash into each other
• Pressure causes the rocks to bend
• Rocks pushed upwards to form mountains

The movement causes earthquakes but not volcanic activity.

Two plates that are moving towards each other.

Example: the Nazca Plate and the American Plate

• Plates move towards each other
• Heavier oceanic plate moves under continental plate
• Plate rub together causing friction and severe earthquakes
• Heat from mantle melts teh rock
• Hot magma rises
• Volcanic eruptions occur

Can cause earthquakes and volcanic activity.