What causes a volcano?

L.O: To know how volcanoes are formed.To know the difference between destructive and

constructive plates.To be able to label a diagram of what happens in a volcano.

What can you remember from last lesson?

• Write something know about the structure of a volcano or a volcanoes shape

• How confident are you that you can describe the main features of a volcano? Where are you on the confidence scale?

1 5 10

NotConfident ok confident

Volcanic cone

Crater

Volcanic bombs

Vent

lava

Magma chamber

How do volcanoes and earthquakes happen?

Match the “top” with the correct “tail” about plate boundaries.

• At a constructive plate boundary...• At a destructive plate boundary...• An oceanic plate is...• A continental plate is...

plates are pushing together under enormous stress causing friction and rock to melt.

heavier rock forced downwards in a destructive plate boundary. lighter rock forced upwards in a destructive plate boundary. plates move apart allowing molten rock through the gap to

create volcanic islands.

Complete the word frame on earthquakes and volcanoes using the word bank below:

The ............... of the earth is made up of enormous sections of rock called .................... / ............... . These plates float on top of the ................ that is made up of ................... rock. The energy in .............. / ........................ causes the plates to move. This movement creates .................. at ............... / ........................ which causes earthquakes and ..................... eruptions. Hot liquid called ................ rises through weaknesses called faults and .............. in the crust to form volcanoes.

magma friction crust tectonic plates plate boundaries mantle molten volcanic heat convections cracks

Sort the following statements in the correct order to show how volcanoes are formed at plate boundaries.

Volcanoes happen at plate boundaries when:• hot molten rock called magma rises through

weaknesses in the crust• friction melts the rock as one plate is forced under

another• plates rub together• volcanoes erupt on the surface• plates move towards each other

What happens when a volcano erupts?

Lava pours down the mountainside

Buildings and property are

damaged

Rescue services go into action

Volcano gently rumbles and

steams

Loud explosion as volcanoe erupts

Ash, bombs and lava blasted out of

volcano.

Watch the animation…

• http://www.youtube.com/watch?v=u2V2kAGp91I&feature=related

Homestudy

• Think about 8 problems volcanic eruptions may cause for either:

• The environment• People that live in the surrounding area

What is the pattern between tectonic activity and plate boundaries?

Ring of Fire

The Pacific Rim is known as the ‘Ring of Fire’. It is 40,000 kilometres long and it is shaped like a horseshoe. It is made up of island arcs, trenches and volcanicmountains.

Amazingly 90% of the world’s earthquakes take place along the ‘Ring of Fire’ because of the severe plate movements.