Whether an eruption will produce lava flows or pyroclastic debris depends on the viscosity of magma and the _______
A) elevation of the volcano
B) age of the magma
C) proportion of volatiles within the magma
D) depth of the magma chamber

Question

Quizplus · Accepted Answer

The proportion of volatiles within the magma determines its viscosity, which in turn determines whether an eruption will produce lava flows or pyroclastic debris. High volatile content leads to low viscosity magma, which is more likely to produce explosive eruptions and pyroclastic debris. Low volatile content leads to high viscosity magma, which is more likely to produce lava flows. The other options (elevation of the volcano, age of the magma, and depth of the magma chamber) can influence the type of eruption in other ways, but not as directly as the proportion of volatiles.

Whether an Eruption Will Produce Lava Flows or Pyroclastic Debris