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Alaska Volcanoes Update
February 13, 1997, 12:30 PM AST (2130 UTC)
Okmok Volcano: 55°24' N, 168°10' W;
caldera rim elevation 3520 feet (1,073 m) elevation of erupting
cone about 2500 feet (760 m)
A small eruption began this morning at Okmok volcano on Umnak Island,
in the eastern Aleutian Islands, about 75 miles west-southwest of
Dutch Harbor. AVO received a report from observers at the
former Fort Glenn military base at the east end of the island at 10:46
am AST that an ash plume began rising from a cone inside the
caldera at about 10 am AST. The dark plume rose to about 5,000
feet ASL, was carried to the southwest by prevailing winds and
was described as dissipating somewhat at the time of the call.
Satellite images from 5 am and 10:30 am AST show a hot spot in
the vicinity of a cone along the south rim of the caldera. AVO
does not have seismic monitoring equipment on the island and
therefore at this time is not instituting a color code designation.
Okmok volcano is a 6-mile-wide caldera that occupies most of the
eastern end of Umnak Island that has had several eruptions in
historic time. Historic eruptions typically consist of ash emissions
occasionally to over 30,000 feet but generally to much lower
altitudes; lava flows crossed the caldera floor in 1945 and 1958.
The last eruption occurred November 1986 through February
1988 and was characterized by intermittent ash emission.
The nearest settlements are Nikolski, population about 35, about 45
miles west of the volcano, and a small number of people at the
abandoned Fort Glenn military base 10 miles east of the volcano.