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

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

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

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

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

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

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

All eruptions are spectacular and explosively violent.

Which type of volcano formed the Hawaiian islands?

Which type of volcano erupted at Parícutin?

Which type of volcano has the most violent eruptions?

Which type of volcano is Mt. St. Helens?