Chapter 6 Volcanoes

Which of the following factors help determine whether a volcanic eruption will be violent or relatively quiescent?

• A) amount of dissolved gas in the magma
• B) temperature of the magma
• C) composition of the magma
• D) all of these

________ tend to increase the explosive potential of a magma body beneath a volcano.

• A) High viscosity and high dissolved gas content
• B) High viscosity and low dissolved gas content
• C) Low silica content and low viscosity
• D) Low viscosity and low dissolved gas content

Which one of the following shows the correct order (left to right) of decreasing magma viscosity in order of composition?

• A) rhyolite, andesite, basalt
• B) andesite, rhyolite, basalt
• C) basalt, rhyolite, andesite
• D) basalt, andesite, rhyolite

Shield volcanoes form from what type of magma?

• A) high viscosity basaltic magmas
• B) low viscosity rhyolitic magmas
• C) low viscosity basaltic magmas
• D) high viscosity rhyolitic magmas

The higher the viscosity of a magma, the ________ the potential for explosive eruptions.

• A) higher
• B) lower

Identify what letter A represents in the diagram.

• A) bomb

• B) lava flow

• C) magma chamber

• D) vent

• E) pyroclastic material

Identify what letter B represents in the diagram.

• A) bomb

• B) lava flow

• C) magma chamber

• D) vent

• E) pyroclastic material

Identify what letter C represents in the diagram.

• A) bomb

• B) lava flow

• C) magma chamber

• D) vent

• E) pyroclastic material

Identify what letter D represents in the diagram.

• A) bomb

• B) lava flow

• C) magma chamber

• D) vent

• E) pyroclastic material

Identify what letter E represents in the diagram.

• A) bomb

• B) lava flow

• C) magma chamber

• D) vent

• E) pyroclastic material