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

Mount St. Helens erupted explosively in 1980. Magma with high silica is thick and has high viscosity, so gases are trapped and pressure can build before an eruption. Therefore, “high-viscosity magma” best describes the eruption; quiet eruptions and gentle lava flows are more typical of less viscous magma.

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