Which mechanism causes explosive eruptions when a subducting oceanic plate is partially melted?

💡 Explanation

When an oceanic plate subducts, water is carried into the mantle; this hydration lowers the melting point of the mantle rock, initiating partial melting and the formation of magma rich in volatile gases. Therefore, hydration-induced lowering produces volatile-rich magma which leads to explosive eruptions, rather than decompression, crystallization, or isostatic processes that require different geological conditions.

• Which phenomenon reduces rainfall within the descending air of Hadley cells?
• Which outcome influences speleothem growth when carbon saturation decreases?
• On a sloping terrain underlain by permafrost, which landform results primarily due to extensive solifluction?
• Which risk increases significantly when low-silica lava erupts subglacially?
• Which process primarily dictates alluvial stratification patterns within an arid region alluvial fan?
• Which mechanism causes thermohaline circulation within a large endorheic lake basin experiencing rapid evaporation?