Volcano Summative Test 2

If a volcano’s magma is high in silica, how will you describe to its volcanic

activity?

• It will erupt quietly

• It will remain dormant

• It will erupt explosively

• It will produce dark-colored lava

Which are needed in the formation of magma?

• composition, pressure, temperature

• composition, pressure, density

• pressure, temperature, distance from the surface

• pressure, temperature, volume

Which is TRUE about the composition of magma?

• It contains ash, dust, and lava

• It contains dissolved gases only.

• It contains fragmented rocks only.

• It contains both dissolved gases and fragmented materials.

Several kilometers from a volcano, a geologist observes an old lava flow

made up of dark- colored basalt rock. The geologist infers that the lava

must have had____________.

• low viscosity

• high viscosity

• medium viscosity

• high silica content

Which is NOT a common gas in magma?

• Methane gas

• carbon dioxide

• sulfur dioxide

• water vapor

Viscosity is a measure of a material’s resistance to flow. Which DOES NOT

affect the viscosity of magma?

• location of magma

• temperature of the magma

• chemical composition of the magma

• presence of dissolved gases in the magma

Which type of lava will offer the least resistance to flow?

• andesitic

• basaltic

• Rhyolitic

• Basaltic and Rhyoliric

The magma in the chamber of a volcano has a very high amount of silica.

If the volcano would erupt, which might happen?

• The lava would flow very slowly

• The volcano would erupt violently

• The volcano would erupt non-explosively

• There would be a build-up of pressure below the crater

What can be inferred about the silica content and temperature of magma

if it has a low viscosity?

• a high silica content and high temperature

• a high silica content and low temperature

• a low silica content and high temperature

• a low silica content and low temperature

Which correctly shows the types of magma in an increasing order of silica

and gas content?

• Andesitic, Basaltic, Rhyolitic

• Andesitic, Rhyolitic, Basaltic

• Basaltic, Andesitic, Rhyolitic

• Rhyolitic, Andesitic, Basaltic