What is the primary factor determining whether a volcanic eruption will be explosive or effusive?
Answer and explanation
Correct answer: B. the silica content and dissolved gas concentration of the magma
- Step 1: High silica content produces viscous magma that traps expanding gases, leading to catastrophic explosive eruptions. Low silica (basalt) allows gases to escape smoothly, producing effusive lava. Answer: the silica content and dissolved gas concentration of the magma. Why not the others: Surface weather and magnetic fields do not control eruptive style.
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