This belt of volcanoes lies largely in Alaska but extends across the border into southwestern Yukon Territory. It formed as a result of melting of the crust due to subduction of the Pacific Ocean plate beneath the North American plate at the Aleution arc. It includes the volcanoes Mt. Wrangell, which has been active historically, and Mt. Churchill, which has had 2 large-magnitude explosive eruptions in the last 2000 years that blanketed most of the Yukon with ash.