Which factor most directly elevates the likelihood of explosive volcanism along subduction zones?

💡 Explanation

When magma has high silica content, its viscosity increases because long silica chains hinder flow, trapping dissolved gases; this build up then erupts violently. Therefore, high silica content promotes explosive volcanism, rather than conditions related to geothermal gradients, chamber depth, or plate speed alone.

• What increased geomorphological process results when vegetation is removed from an alluvial floodplain?
• Which effect increases when humid air flows poleward?
• Which wind shift pattern results from Coriolis effect deflection relative to high pressure systems in northern hemisphere?
• Which risk increases with prolonged water saturation of an aging earthen levee structure?
• Which mechanism causes oxbow lake formation when a river's meander neck narrows during floodplain evolution?
• Which outcome develops because of glacial retreat forming increased alluvial deposition?