Which mechanism causes caldera formation after a Plinian eruption in a stratovolcano?

💡 Explanation

When a large Plinian eruption of a stratovolcano empties the magma chamber, the reduced internal pressure can no longer support the volcano's structure leading to inward collapse. This collapse mechanism forms a large caldera rather than other eruption products. Therefore, magma chamber roof collapse results, as the other options do not relate to caldera formation.

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