| ANCHORAGE, Alaska
ANCHORAGE, Alaska May 4 A remote but
long-restless Alaska volcano rumbled to life on Saturday with
three explosions and started emitting a continuous plume of ash,
steam and gas in an area important to air traffic, scientists
The low-level explosions at Cleveland Volcano, which lies
below a major air-traffic route between North America and Asia,
were not severe enough to cause a significant threat to planes,
But the incident did prompt federal aviation authorities to
divert some traffic north of the volcano as a precaution, said
Rick Wessels, a U.S. Geological Survey geophysicist at the
Alaska Volcano Observatory.
"Based on the signals we can see, we think it's continuously
in an eruption right now," Wessels said of the volcano, located
940 miles (1,500 km) southwest of Anchorage.
Cleveland Volcano, which has been restless since mid-2011,
is on an uninhabited island in one of the most sparsely
populated regions of the world, although major eruptions could
cause potential aviation threats.
Federal Aviation Administration officials could not
immediately be reached for comment.
The 5,676-foot volcano began oozing lava in the summer of
2011, causing lava domes to form at the crater and allowing
pressure to build inside the peak. There have since been 20 to
25 explosions at sporadic intervals, he said.
But Saturday's trio of explosions was a new turn of events,
"We haven't seen a phase like this where we've had multiple
explosions," he said.
So far, the cloud streaming from Cleveland's crater has
reached only about 15,000 feet into the atmosphere - too low to
cause damage to higher-flying jet airliners. "Once it gets to
about twice that, we get really worried," Wessels said.
If the eruption becomes stronger, the National Weather
Service will advise mariners to avoid the area, he said. Still,
scientists have been put on around-the-clock duty to try to
track Cleveland's activities, he said.
"It's got us all paying attention. We're not sure if it will
escalate or do what Cleveland does, which is to settle down
after small explosions," he said.
It is difficult for scientists to monitor Cleveland Volcano
because there is no seismic equipment on the mountain. Alaska
Volcano Observatory scientists rely on satellite data, signals
from a different volcano about 50 miles away, eyewitness reports
and other information.
Cleveland Volcano, which occupies about half of Chuginadak
Island, is the only one of Alaska's 90 active volcanoes believed
to have killed a person in an eruption.
A soldier on the island during World War Two disappeared
during an eruption, according to Observatory scientists.
(Editing by Cynthia Johnston and Andrew Heavens)