Whether an eruption will primarily produce lava flows or pyroclastic debris is influenced by ____________.
A) the viscosity of the lava
B) the composition of the lava
C) the proportion of volatiles within the lava
D) all of the above

Question

Quizplus · Accepted Answer

All of the given factors, viscosity, composition, and proportions of volatiles, can influence whether an eruption will produce primarily lava flows or pyroclastic debris. Lava with lower viscosity is more likely to produce flows, whereas more viscous lava will fragment and produce pyroclastic debris. The composition of lava can also affect its behavior: felsic (more silica-rich) lava is more explosive and more likely to produce pyroclastic debris. Finally, the proportion of volatiles (gases) within the lava can affect the explosiveness of an eruption, with more volatile-rich lava being more explosive and more likely to produce pyroclastic debris.

Whether an Eruption Will Primarily Produce Lava Flows or Pyroclastic