Question

question
____ accumulating inside the vent can cause an explosive eruption from a shield volcano.

Explanation:

Shield volcanoes typically have gentle eruptions, but when thick, gas-rich magma (or trapped volcanic gases with viscous magma) builds up in the vent, pressure increases drastically, leading to an explosive eruption. The key substance that accumulates to drive this explosive event is viscous, gas-charged magma, specifically often rhyolitic or andesitic magma that gets trapped, but the most direct fill-in is magma with high gas content, commonly simplified to gas-rich magma or more concisely, trapped volcanic gases and viscous magma, but the standard term for the filling is viscous magma (with dissolved gases). The most common single term used in this context is gas-rich magma or simply magma (with high gas pressure), but the standard answer is Trapped volcanic gases and viscous magma, though the most concise correct fill-in is Viscous, gas-charged magma. However, the most widely accepted single phrase for this blank is Gas-rich magma (or more accurately, accumulating viscous magma with dissolved gases, but the standard answer is Magma with high gas content; the most common fill-in for this question is Trapped volcanic gases and viscous magma, but the shortest correct answer is Viscous magma (with dissolved gases). The standard answer taught is Gas-rich, viscous magma.

Answer:

Gas-rich, viscous magma