North Pacific High Sea

The open ocean south of the Aleutian Islands is crossed by the westward-flowing Alaskan Stream. Some of its water turns north through the island passages and enters the Bering Sea beyond. Beneath the waves, the deep Aleutian Trench runs along the island arc, marking the place where the Pacific ocean floor descends beneath North America. That same movement has built the volcanic peaks rising from the sea to the north.