Chapter 9 Earth Science Volcanoes

Openings in the Earth's crust through which molten rock flows to the surface, usually forming mountains, are called __________.

• volcanoes

• earthquakes

• faults

• magma

Tectonic plates move at a rate of several __________ per year. 

• centimeters
• miles
• light years
• kilometers

The major belt of volcanoes and tectonic activity that surrounds much of the Pacific Ocean:

• Ring of Fire

• Ring of Asia

• Ring o' earthquakes

• Ring a ding ding

What is molten rock that has reached the Earth's surface called?

• Aa

• Lava

• Magma

• Pahoehoe

What factor(s) determine(s) whether an eruption will be explosive?

• Only the amount of gases in the magma

• Only the day of the week the eruption happens on

• Both the amount of gas and silica in the magma

• None of these affect the explosiveness of the volcano

Vocanoes are found...

• on land

• under water

• on islands

• all of the above

A live volcano is called a/an:

• Dormant volcano

• Active volcano

• Extinct volcano

• Shield volcano

A sleeping volcano

• Composite volcano
• Active volcano
• Extinct volcano
• Dormant volcano

A dead volcano, one that is unlikely to erupt again

• Dormant volcano
• Extinct volcano
• Shield volcano
• Caldera

Why does magma tend to rise to the surface?

• It has large amounts of silica.
• It contains very little silica.
• It is denser than the surrounding material.
• It is less dense than the surrounding material.