Here's why:

* Subduction: The African Plate is subducting (diving) beneath the Eurasian Plate in this region.

* Volcanic Arc: This subduction process creates a volcanic arc, which is a chain of volcanoes that form along the edge of the overriding plate. Mount Stromboli is part of this volcanic arc.

Important Note: While Stromboli is on a convergent plate boundary, it's not a typical subduction zone volcano. It's a stratovolcano that erupts frequently, but in a relatively predictable and less explosive way. This is due to the specific conditions of the subduction zone in this area.