Ioto (硫黄島, also known as Iwo-jima) volcano is a triangular-shaped, flat, 8 km long and up to 4.5 wide volcanic island stretching NE-SW. It is surrounded by steep cliffs under the sea, which belong to a 9-km-wide submarine caldera. The volcano is located 1250 km south of Tokyo in the central Volcano Islands of the Izu-Marianas arc.
The summit of Iwo-jima is Suribachi-yama at 160 m.
Parts of the caldera have been experiencing remarkably strong uplift (up to more than 1 meter per year and averaging 25 cm / year over several centuries). There is strong hydrothermal activity at present, at fumaroles along a NE-SW zone cutting through Moto-yama. Many phreatic eruptions occurred in historic times, mostly from vents on the west and NW sides of the island.
Iwo-jima was the site of an infamous WWII battle, and the location of a famous image of the raised US flag.
caldera 161 m / 528 ft
Volcano Islands, Japan, 24.75°N / 141.29°E
Current status:
dormant (1 out of 5)
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ReportsIwo-jima volcano booksIwo-jima volcano eruptions:2012, 2001, 1982, 1980, 1978, 1976, 1974 (?), 1969 (?), 1967, 1957, 1943
Typical eruption style:explosive
Last earthquakes nearbyLatest satellite images
Latest news & activity updates:
Thu, 6 Jun 2013, 10:05
The latest report from the Japan Meteorological Agency (which is always published with one-month delay) indicates that a small phreatic eruption occurred on 11 April this year.
...moreThe volcano has had similar phreatic explosions in the recent years. As most of the previous ones, this latest one occurred from the "Old Crater" also known as the the "Million Dollar Hole" - a nickname that dates back to WW2 when US soldiers after a battle on the island in 1945 used the crater to store equipment and supplies. [
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Mon, 10 Dec 2012, 05:51
Visual observation via a camera installed at Asodaihigashi (about 900 m east-northeast of the Asodai collapse pit) showed that the volume of fumes from the pit (located at the west of Ioto Island) was small, and that their heights ranged from 0 to 100 m.
...moreNo fumes were observed at Idogahama to the northeast of the island.
Seismic activity remained at low levels. A volcanic tremor was observed at 20:22 JST on November 27th, which lasted for duration of no more than 1 m 10 s. No changes in volcanic earthquake conditions, infrasound and surface phenomena were observed during this event. Volcanic tremor was observed for the first time since July [
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Thu, 3 May 2012, 08:35
According to a JMA report on 2 May, an eruption at Ioto (Iwo-jima) caused water discoloration to the NE. A new fumarole was also confirmed.
