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Country: | Japan | |
| Subregion Name: | Volcano Islands (Japan) | ||
| Volcano Number: | 0804-12= | ||
| Volcano Type: | Caldera | ||
| Volcano Status: | Historical | ||
| Last Known Eruption: | 2001 | ||
| Summit Elevation: | 161 m | 528 feet | |
| Latitude: | 24.754°N | 24°45'13"N | |
| Longitude: | 141.290°E | 141°17'25"E | |
| Ioto (also known as Iwo-jima) in the central Volcano Islands portion of the Izu-Marianas arc lies within a 9-km-wide submarine caldera. Ioto, Iwo-jima, and Io-jima are among many transliterations of the name, which means "Sulfur Island;" the volcano is also known as Ogasawara Io-jima to distinguish it from several other "Sulfur Island" volcanoes in Japan. The triangular, low-elevation, 8-km-long island narrows toward its SW tip and has produced trachyandesitic and trachytic rocks that are more alkalic than those of other Izu-Marianas arc volcanoes. The island has undergone dramatic uplift for at least the past 700 years accompanying resurgent doming of the caldera. A shoreline landed upon by Captain Cook's surveying crew in 1779 is now 40 m above sea level. The Moto-yama plateau on the NE half of the island consists of submarine tuffs overlain by coral deposits and forms the island's high point. Many fumaroles are oriented along a NE-SW zone cutting through Moto-yama. Numerous historical phreatic eruptions, many from vents on the west and NW sides of the island, have accompanied the remarkable uplift. | |||
![Ioto [Iwo-jima] Photo](/images/small/095054.jpg)