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.

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