Iwo-jima (Ioto) volcan éruptions
caldeira 161 m / 528 ft
Volcano Islands, Japon, 24.75°N / 141.29°E
Liste des éruptions: 2001, 1982, 1980, 1978, 1976, 1974 (?), 1969 (?), 1967, 1957, 1943
2001 eruption
A submarine eruption occurred from 3 vents SE of Iwo-jima volcano on 21 September 2001. The activity built 10 m diameter pyroclastic cone on that day. Until 19 October, there was no further activity, but on 19 October a small phreatic eruption occurred at Idogahama, the name of a beach on the NW coast of the island. the explosion formed a new crater 10 m wide and 2-3 m deep.
1982 eruption
On 9-10 March 1982, 5 phreatic eruptions occurred from vents on the NW shore of Iwo-jima island.
1957 eruption
A phreatic eruption occurred at Iwo-Jima volcano on 28 March 1957. The eruption occurred without warning 2 km NE of Suribachi-yama. The eruption lasted for 65 minutes and ejected material 30 m high from a single crater. A second crater formed by collapse 50 minutes after the eruption ended. The collapse crater was 30 m wide and 15 m deep. Gas emissions increased on 31 March, and 3 dead birds were found in the crater.
Source: Gilbert Corwin, and H. L. Foster (1959) "The 1957 explosive eruption on Iwo Jima, Volcano Islands", American Journal of Science, Vol. 257, pp. 161-171
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Abstract from Gilbert and Foster (1959), about the 28 March 1957 eruption:
"An explosive eruption occurred without warning on March 28, 1957, near the center of Iwo Jima, a small volcanic island midway between Guam and Tokyo, Japan. The eruption of steam, volcanic sand, and volcanic sandstone and conglomerate blocks began suddenly at 11:55 A.M. local time, continued for 65 min., and ended abruptly. Coarse ejecta were thrown as high as 150 ft.; dust and steam rose to heights of 200 to 300 ft. No juvenile material was ejected. An elliptical crater 90 to 110 ft. in diameter and 45 ft. deep resulted. Deposits were concentrated to the western (lee) side where they ranged in thickness from 22 ft. near the crater to less than one inch 300 ft. to the W. About 50 min. after the eruption a second crater formed by collapse 75 ft. NW. of the eruption crater. The circular collapse crater was 115 ft. in diameter and 55 ft. deep. Many ground cracks and small faults with displacements up to 8 in. were formed nearby during and following the eruption. Steam and other gases issued from the craters, faults, and cracks following the eruption, and some sublimates were deposited. No significant change of fumarolic activity was noted on other parts of the island before, during, or after the eruption. The eruption resulted from the sudden release of an underground accumulation of steam under high pressure beneath artificial fill adjacent to an abandoned airfield. The eruption does not seem to indicate an increase in volcanic activity on Iwo Jima."