Explosive volcanic eruptions occur ________.
A)when crystallization forces exceed the strength of the volcano
B)in response to deflation of the volcano
C)when violently escaping gases evolve suddenly to drop the magma density and propel molten magma from the chamber
D)whenever basaltic magma extrudes on the seafloor

Question

Quizplus · Accepted Answer

Explosive volcanic eruptions occur when violently escaping gases (such as water vapor, carbon dioxide, and sulfur dioxide) evolve suddenly, dropping the magma density, and propelling the molten magma from the chamber. The gas pressure builds until it exceeds the strength of the rock or the confining pressure holding it down, leading to a sudden release of energy and an explosive eruption.

Explosive Volcanic Eruptions Occur ________