9-1: The Nature of Volcanic Eruptions

The degree to which a substance is resistance to flow is known as its:

• viscosity

• volatiles

• eruption columns

• aa flows

• pyroclastic materials

The gaseous components of magma (mostly water) are known as:

• viscosity

• volatiles

• eruption columns

• aa flows

• pyroclastic materials

A lava flow that has a rough surface, jagged blocks with dangerous sharp edges and spiny projections is called:

• viscosity

• volatiles

• eruption columns

• aa flows

• pyroclastic materials

Particles of ejected lava produced from volcanic eruptions that range in size from ash and dust to much larger blocks and bombs are called:

• viscosity

• volatiles

• eruption columns

• aa flows

• pyroclastic materials

Which of the following is not a factor that determines how violently a volcano will erupt?

• magma temperature

• magma composition

• magma dissolved gas amount

• magma color

In general, the more silica in magma, the ______________ its viscosity.

• lower

• greater

Eruptions of fluid basaltic lavas, such as those that occur in Hawaii, tend to be:

• extremely violent

• explosive

• relatively quiet

• unpredictable

In 1980, one of the most violent eruptions to occur in North America in recent historic times happened at:

• Mt. Hood

• Mt. St. Helens

• Mt. Shasta

• Mt. Pinatubo

• Kilauea

All eruptions are spectacular and explosively violent.

• True

• False

Which type of volcano formed the Hawaiian islands?

• shield volcanoes

• composite volcanoes

• cinder cone volcanoes

• stratovolcanoes