Volcanic Eruptions and Rock Types

What happened to Mount St. Helens on May 18, 1980?

• It was flooded.

• It was covered in snow.

• It erupted explosively.

• It was hit by a meteor.

What can make a volcanic eruption hard to predict?

• The color of the lava.

• The size of the volcano.

• The explosive nature of eruptions.

• The height of the mountain.

What can cause a volcano to erupt explosively?

• A large amount of gas and water vapor in magma.

• A lot of rain.

• A small amount of ash.

• A low temperature.

What type of rock is formed from magma low in silica?

• Granite

• Limestone

• Basalt

• Sandstone

How do basalt-rich volcanoes usually erupt?

• Very explosively

• With a lot of smoke

• With a lot of noise

• Slowly and less violently