ANCHORAGE— An Alaska volcano that has been erupting periodically for more than seven months sent up another ash cloud, prompting a warning to trans-continental aircraft.
Bogoslof Volcano, in the Aleutian Islands about 850 miles (1,400 kilometers) southwest of Anchorage, erupted at 10 a.m. Monday and spewed ash for three hours until about 1 p.m.
Satellite data showed the eruption rising above clouds at 1,500 feet (450 meters). A pilot later reported seeing the ash cloud at 32,000 feet (9,750 meters).
Bogoslof Volcano is a cone-shape structure with its base 5,500 feet (1,675 meters) under water on the floor of the Bering Sea. The tip forms tiny Bogoslof Island, and previous eruptions have added or subtracted acreage.
The volcano has erupted about 60 times since mid-December, said Dave Schneider, a U.S. Geological Survey geophysicist with the observatory, usually in spurts far less than three hours. Previous eruptions have been from vents under the sea.
“We think this was still underwater today,” Schneider said.
Ash clouds above 20,000 feet (6,100 meters) can harm jet airliners traveling between Asia and North America on the Great Circle Route. Sharp volcanic ash can damage and even stop jet engines.
Pilots warned of ash clouds fly over or around them to avoid engine damage.
Satellite images in early afternoon showed a continuous ash cloud still attached to the volcano, according to the observatory.
Winds pushed the cloud south. Ash was not expected to present a danger to Alaska communities.
Low-level ash emissions may have continued. The observatory said seismic activity declined but remained above background levels and that emissions could intensify without warning.
