Why are there so many volcanoes in the Aleutian Range and Aleutian Islands?

The high concentration of volcanoes in the Aleutian Range and the Aleutian Islands is primarily due to their location along a subduction zone.12

In this region, the Pacific Plate is converging with and moving beneath the adjacent North American Plate. As the Pacific Plate is forced down into the mantle, it undergoes a process of subduction, which generates molten rock that rises to the surface to form volcanoes. This geologic setting creates an island arc—a long, curved chain of volcanic peaks—that stretches from the Alaska Peninsula to the western end of the Aleutian chain.213

These volcanoes are typically of the explosive type and are responsible for building the mountainous peaks that characterize the region. More than 80 volcanoes have been mapped in this chain, with approximately half having been active within the last few centuries.123