August 10, 2011

Alaskan Volcano Puts On Fiery Show

On the remote, uninhabited Chuginadak Island in Alaska, a volcano has begun erupting, but poses little danger to people or aircraft, officials said Tuesday.

The Cleveland volcano is erupting with a slow effusion of magma, forming a lava dome.

It is not an explosive eruption that generates large ash plumes, explains John Power, the scientist-in-charge at the Alaska Volcano Observatory. "So far, it's just lava as far as we can tell from our satellite imagery and the people who have managed to see it from passing airplanes," Powers told teh Associated Press (AP).

"Certainly, if there were people who were going to be in the area, they would need to be concerned but there aren't many of those folks there right now," he continued.

With the lava dome confined within the summit crater, there is little to fear. The biggest danger would be if the lava dome began to grow large enough to spill out, then it could begin to generate ash-producing explosions, "Then it would be a much more dangerous situation," he said.

Past observations at several similar volcanoes have shown dome growth like this can go on for weeks to months. "It's something we're going to be watching very closely, or as close as we can given our operational constraints there," Powers explained.

Officials are not able to track local earthquake activity related to volcanic unrest as there is no real-time seismic network at the volcano. Researchers must rely on satellite imagery or direct observations from flights passing by the volcano and reported to the observatory.

Given the current level of activity and hazards, he said they don't plan to fly to the volcano, especially considering the expense but weather has cleared in the last few days to allow better satellite imagery.

"We've had a few good days where the top of the volcano has been sticking out of the clouds, so things are looking nice for us in terms of direct observations," Power said.

Short-lived explosions with ash clouds or plumes exceeding 20,000 feet above sea level are frequent on Cleveland. It last showed signs of unrest last summer, with a small ash emission and lava flows on its upper flanks.

The observatory says the last significant eruption of the 5,676-foot volcano began in February 2001 and eventually produced a lava flow that reached the ocean.


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