Located south of
Tokyo and south of
Iwo Jima, The main cone of the Hiyoshi complex, the Minami-Hiyoshi is a stratovolcano with a base diameter of with a height above the seabed around . The
submarine volcano complex involves four submarine volcanic peaks; Kita-Hiyoshi, Naka-Hiyoshi, Minami-Hiyoshi and the Ko-Hiyoshi submarine volcanoes. This complex is geologically connected to the Izu-Mariana arc.
Composition Unlike volcanoes of the south and central parts of the Mariana volcanic arc, which usually are made of low-
alkali and mid-alkali
tholeeite basalt, the Hiyoshi complex includes more alkaline lava with more
K,
Ba and
Sr. ==Recent activity==