Minami-Hiyoshi Seamount

The Minami-Hiyoshi Seamount is an active seamount in the Bonin Islands of Japan.

Geography

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 tholeiitic [magma series|tholeeite] basalt, the Hiyoshi complex includes more alkaline lava with more K, Ba and Sr.

Recent activity

In a report about the seismic activity of the volcano compiled in 2003, the active cone, Minami-Hiyoshi was reported to have "low activity" over the period of a month in 2001. Other than that, Minami-Hiyoshi has had many periods of activity including 1975, 1976, 1977, 1978, 1992 and 1996.