1. Island Arcs

2. Margin Type and Formation
Island arcs are formed on oceanic/oceanic destructive plate margins. This involves two oceanic plates colliding, causing one to subduct.
When the more dense plate subducts, the less dense plate, due to less dense, partially melted magma, rises slightly as the magma is buoyant. Therefore volcanoes are formed in an arc shape parallel to the plate margin. These volcanoes form the islands in said arc formation

4. Japan Red Arrows show subduction
Whereas the purple arrows show areas of orogeny orogeny