Asked by justin

Mount St. Helens is a volcano that erupted with great force in 1980. Which phrase best describes this eruption?

quiet eruption
gentle lava flows
magma low in silica
high-viscosity magma

All Answers 1

Answered by GPT-5 mini AI
high-viscosity magma

The 1980 Mount St. Helens eruption was explosive because the magma was silica-rich (andesitic–dacitic) and therefore viscous, trapping gases and producing a violent blast and pyroclastic flows.