Ryukyu volcanic arc - 5 - Io-Torishima

Io-Torishima (Iwo Torishima) is a tiny island, the southernmost of the group of Nansei islands uninhabited, of  2,700 m by 1000 m.

Not to be confused with other, Torishima, or Bird Island, is a name commonly used to refer to Japanese islands offshore (as in the Izu arc, further north-east), it is better to call Okinawa-Torishima.

It consists of two or three according to sources, andesitic volcanoes that overlap.

The Io-dake (Iwo-dake, Sulfur peak) forms the northwest side of the island; it contains a small lake, sulfur springs and sulfur deposits exploited in the past.
The Gusuku, a lava dome occupies the center of two broods sommas, south-east.  the highest point, Mae-dake, is located at the SE point of the island.

The activity after 1664 is described as "middle to moderate explosive activity" by the GVP; major eruptions occurred in 1664, 1796, 1829, 1855, 1868, 1903, 1959, 1967 and 1968, the last official activity. (dates highlighted were of VEI 2).

A possible small eruption was reported July 7, 2013 by a pilot to VAAC Tokyo, which has not detected against ash plume on satellite images.