Nishi-no-shima is a volcanic island located around 940 km south-southeast of Tokyo, that is part of the Volcano Islands arc. Nishinoshima is located about 130 km to the west of the nearest of the Ogasawara islands, hence the name, but the other Ogasawara island groups are aligned north-south. The nearest of the other Volcano islands is over 270 km away, but Nishinoshima is on the alignment of the Volcano islands. It was formed by ash from a underwater volcanic eruption.