Cleveland volcano explodes as epidemic of awakenings across planet continues

March 8, 2012 – ALASKA – A restless Aleutian volcano exploded Wednesday night and may have blown off a slow-growing lava dome that was building for months in its summit crater, volcanologists say. Cleveland Volcano, 940 miles southwest of Anchorage, probably burped up a small amount of ash — a potential hazard to trans-oceanic air travel — but the ash did not appear to reach above 20,000 feet, said Steve McNutt, a researcher with the Alaska Volcano Observatory. Because of its remoteness, harsh weather in the area and budget constraints, Cleveland Volcano does not have instruments on its flanks. As a result, scientists cannot listen to its inner rumblings. But distant seismometers and specialized microphones detected the explosion about 7 p.m. Wednesday, according to the observatory. The explosion caused a displacement of air and an airwave traveled out from the volcano at the speed of sound, McNutt said. Instruments at volcanoes 60 and 90 miles away detected the explosion several minutes after it occurred, he said. Clouds on Wednesday and today prevented clear satellite views, so scientists are not sure exactly how much ash may have shot out of the 5,676-foot volcano, which makes up the western half of Chuginadak Island. “It is the Aleutians in winter, after all,’ McNutt said. Either way, the researchers do not think the volcano poses an immediate threat to planes. McNutt thinks the explosion blasted away a lava dome building inside the volcano’s summit crater. As the thick, pasty molten rock flows slowly into the crater, it piles up and plugs gas vents, he explained. An explosion can occur when the gas builds up enough pressure, McNutt said. –ADN