This is an aerial view of Aogoshima Island, one of about a dozen volcanic islands south of Tokyo in the Philippine Sea, seven of which are inhabited. Aogoshima is the southernmost of these inhabited islands.
In the Western Pacific, the Pacific Plate is subducting beneath a series of plates, including the Eurasian plate to the North beneath Japan and the Philippine Sea plate here. That subduction leads to a linear series of volcanoes trending south from Tokyo where the Pacific, Philippine Sea, and Eurasian Plates meet.
The island shows a gorgeous set of volcanic structures. The outer ring of the island is a large collapsed caldera; a gap created when the volcano above erupted, clearing space in the magma chamber into which the peak collapsed. After the large eruption that produced the caldera, volcanic activity continued and a smaller peak has re-grown in the center.
Eventually, this peak may well grow large enough to dominate the island and collapse into a caldera again, a continuing cycle seen with many large volcanic systems. Via EarthStory