Origin and Making of Magma

Volcanoes can erupt in different ways, depending on the magma ________.

Thick, sticky, high-silica magmas are so viscous that they tend to erupt less easily, causing the pressure within a volcano to ________.

The activity of a volcano depends on the ________ of the magma.

Pressure increases with depth because of the weight of overlying rocks. True or False

As pressure increases, the temperature at which a substance melts also increases. True or False

As magma rises, the pressure on the magma ________ and more melting can occur.

Lava from an eruption can be thin and runny or thick and lumpy. True or False

As the magma is forced upward into the lithosphere, it can cause cracks to form in the crust. These cracks provide channels or ________ for the magma to reach the surface.

Because magma is a liquid, it is ________ dense than the rock around it.

Because magma is a liquid, it is more dense than the rock around it. True or False

A ________ is a feature that forms when magma reaches the surface.

Temperature and composition of a magma that ultimately erupts as lava can be linked to the type of _____ ________ associated with it.

The runny, low-silica, high-temperature basaltic lavas are so low in viscosity that they erupt quite easily and often produce ________ eruptions of freely flowing lava.

In some places in the asthenosphere, some melting has occurred. Melted rock inside Earth is called ________.