The Pavlof Volcano in southwest Alaska erupted Sunday afternoon
sending plumes of ash 3,700 feet high and 400 miles inland across Alaska
prompting the cancellation of dozens of òights.
In a new release late on Monday
night, the U.S. Geological Survey
said that the intensity of the
eruption had “declined
signiÒcantly.”
The Star reports:
Pavlof Volcano, one of Alaska’s
most active volcanoes, is 1005
kilometres southwest of
Anchorage on the Alaska
Peninsula, the Ònger of land that sticks out from mainland Alaska toward the
Aleutian Islands.
The volcano in the 8,261-foot (or 2518-metre) mountain erupted about 4 p.m.
Lightning over the mountain and pressure sensors indicated eruptions
continued overnight Sunday. By 7 a.m. Monday, the ash cloud had risen to 11,
300 metres and winds to 80 km/h or more had stretched it over more than
640 kilometres into interior Alaska.
“It’s right in the wheelhouse of a lot of �롓ights criss-crossing Alaska,” said
geologist Chris Waythomas, of the U.S. Geological Survey, part of the Alaska
Volcano Observatory, along with the University of Alaska and the state
Division of Geological and Geophysical Surveys.
In its statement late Monday, the
USGS said that the volcano’s
activity decline began around
noon Monday and that by late at
night a continuous emission was
no longer being observed by
satellite.
Consequently, a volcano alert —
that had been at its highest level,
warning of hazards both in the air
and on the ground — was
downgraded from a warning to a watch.
But the agency said that a signi롱cant eruption was still possible
Earlier in the day, Alaska Airlines said it cancelled 41 教菾ights a쾍餞ecting about
3,300 customers heading to Fairbanks, Bethel, Kotzebue, Nome, Barrow and
Deadhorse. The airline said it will resume its 54 regularly scheduled 教菾ights on
Tuesday if conditions improve.
Volcanic ash is angular and sharp and has been used as an industrial abrasive.
The powdered rock can cause a jet engine to shut down. USGS geologists have
compared it to 教菾ying into a sand blaster.
An eruption of Mount Redoubt in December 1989 sent out an ash cloud 241
kilometres that 教菾amed out the jet engines of a KLM 教菾ight carrying 231
passengers to Anchorage. The jet dropped more than 3 kilometres before
pilots were able to restart the engines and land safely.
“We just simply will not 教菾y when ash is present,” Alaska Airlines spokeswoman
Bobbie Egan said.
Waythomas had received no reports of ash falling in communities. The closest
community, Cold Bay, is 60 kilometres southwest of the volcano, opposite of
where the wind was blowing ash.
Geologists call Pavlof an open-system volcano, Waythomas said.
“The pathways that magma follows to the surface are pretty open in a
volcanological sense,” Waythomas said. “They can convey magma and gas very
easily. Magmas can move to the surface whenever they feel like it, more or
less.”
The movement comes with little shaking of the ground, and the lack of
earthquakes as an early warning of an eruption “makes us go crazy
monitoring them,” Waythomas said.
The volcano, about seven kilometres in diameter, has had 40 known
eruptions. Its conical, nearly symmetrical shape indicates its eruptions tend to
be less violent than the kind that blows tops o쾍餞 mountains.
“It can erupt for periods of hours to
days or it can go on for much longer
periods of time,” Waythomas said. “It
won’t erupt continuously for many
months or a year. It will be
intermittent. But the eruption cycle
could go on for a while, or it could
abruptly shut o쾍餞 and be done