Why do Alaskan volcanoes erupt so often? In this photo taken Tuesday, May 26, 2009, people dig for razor clams on the beach of Ninilchik, Alaska, as Redoubt volcano vents steam on the other side of Cook Inlet. (AP Photo/Al Grillo/Lynda Lybeck Robinson via AP)
Why do Alaskan volcanoes erupt so often?
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A remote volcano in Alaska's Aleutian Islands has erupted 10 times in less than a month. Experts say more eruptions are possible.
 
Bogoslof volcano has sent up ash clouds that have reached as high as 35,000 feet.
 
The Alaska Volcano Observatory is a joint program of the U.S. Geological Survey and the University of Alaska Fairbanks. It says 90 volcanoes have been active within the last 10,000 years. And they could erupt again. More than 50 have been active since about 1760. That is when record-keeping began.
 
Like Bogoslof, most are on the 1,550-mile-long Aleutian Arc. The area forms the northern portion of the Pacific "Ring of Fire." The ring is a horseshoe-shape zone around the Pacific Ocean of frequent earthquakes and volcanic eruptions. These are triggered by the subduction of an oceanic plate beneath continental plates.
 
Volcanoes in Alaska erupt regularly. Pavlof Volcano sent up ash clouds in 2013. Cleveland volcano blew in December 2011. Redoubt volcano 100 miles southwest of Anchorage blew in March 2009, dropping ash during the medals ceremony for the U.S. alpine ski championships at Alyeska Resort in Girdwood. Some volcanoes erupt and spit out additional ash intermittently for weeks, as Bogoslof seems to be doing.
 
The Alaska Volcano Observatory was formed in response to the 1986 eruption of Mount Augustine. The observatory has tools to predict eruptions. As magma moves beneath a volcano before an eruption, it often generates earthquakes. They swell the surface of a mountain and increase the gases emitted. The observatory samples the gases. It also measures earthquake activity and watches for landscape deformities.
 
The observatory uses mathematical models to forecast how fast ash particles will be transported in the atmosphere. And to determine where ash could fall. The observatory runs the models when it detects that a volcano might erupt. It also updates them when they blow.
 
What makes Alaska volcanoes so dangerous? Volcanoes in Hawaii ooze lava. But volcanoes in Alaska tend to explode.
 
Instead of a red river of lava, Alaska volcanoes typically shoot ash up to 50,000 feet. That is more than nine miles. It reaches the jet stream.
 
That ash is not the kind you left after a campfire. Instead, it's an abrasive kind of rock fragment. The particulate has jagged edges. It has been used as an industrial abrasive to polish metals.
 
Particulate can injure skin, eyes and breathing passages. The young, the elderly and people with respiratory problems are especially susceptible. Ash under a windshield wiper can scratch glass. However, most volcanoes are far from communities. So ash fall that requires breathing masks or new air filters on a car is infrequent.
 
USGS geophysicist John Power once likened flying through an ash cloud to flying into a sandblaster.
 
Ash can scrape the moving parts of jet engines such as turbine blades. However, ash on hot parts of a jet engine is potentially more dangerous, according to the observatory. The engines operate near the melting temperature of volcanic ash.
 
"Ingestion of ash can clog fuel nozzles, combustor, and turbine parts causing surging, flame out, immediate loss of engine thrust, and engine failure," according to the observatory.
 
Using information provided by the Federal Aviation Administration, the observatory estimates that more than 80,000 large aircraft per year, and 30,000 people per day, fly on routes downwind of Aleutian volcanoes. These are along great-circle routes between Europe, North America and Asia.
 
Airlines get excited when an ash cloud rises above 20,000 feet.
 
The jet stream can carry ash for hundreds of miles. Ash from Kasatochi Volcano in August 2008 blew all the way to Montana.
 
Redoubt volcano blew on Dec. 15, 1989. It sent ash 150 miles away into the path of a KLM jet carrying 231 passengers. Its four engines flamed out.
 
As the crew tried to restart the engines, "smoke" and a strong odor of sulfur filled the cockpit and cabin. The jet dropped more than 2 miles, from 27,900 feet to 13,300 feet. The crew finally was able to restart all engines. The plane landed safely at Anchorage.
 
So what are the chances for a major, catastrophic eruption?
 
"That's always a possibility but big eruptions have precursor signals," said USGS research geophysicist Chris Waythomas. "That just doesn't happen in 20 minutes."
 
Months of below-ground unrest can precede a major eruption. The Alaska Volcano Observatory, Waythomas said, likely would be tipped off by movement of the huge volume of magma involved.
 
"It has to break a lot of rock to get to the surface," he said.

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CRITICAL THINKING QUESTION
Why do Alaskan volcanoes explode?
Write your answers in the comments section below


COMMENTS (23)
  • samanthas-1-ste
    1/12/2017 - 01:09 p.m.

    The Alaskan volcanoes explode because of their position and inside. They are in the Ring of Fire, a popular volcano eruption chain. Also, is doesnt spit out lava, but ash instead.

  • jacklynt-ste
    1/12/2017 - 01:56 p.m.

    This is really interesting! It would not cross my mind that volcanoes would actually be in Alaska let alone explode often. I have always wanted to visit Alaska, but maybe now I will rethink that vacation.

  • richardk-orv
    1/12/2017 - 03:00 p.m.

    I think Alaskan volcanoes explode because Alaska is a state that is in a ring of fire. Also Alaska has a different type of lava.

  • nathanm14-ste
    1/13/2017 - 01:25 p.m.

    I'm glad to live in the middle of a tectonic plate nice and safe on the boring old east coast. No earthquakes, no hurricanes, no twisters, oh yeah, and no volcanos! Living even relatively close to a volcano would just be terrifying.

  • scarletts-jen
    1/17/2017 - 10:29 a.m.

    the cold temp will stop the lava but the lava will turn in to sharp ash that explodes

  • jackiek-orv
    1/17/2017 - 11:26 a.m.

    Alaskan volcanoes explode a lot because they are in the Ring of Fire which is a popular volcano eruption chain.

  • hayleel-ste
    1/17/2017 - 06:49 p.m.

    I am glad to live where I do. No cruel weather conditions or natural disasters. Maybe a little flooding every once in a while but I would take a little water over a volcano any day.

  • kmadison-dav
    1/18/2017 - 04:43 p.m.

    Bogoslof volcano has sent up ash clouds that have reached as high as 35,000 feet. Redoubt volcano 100 miles southwest of Anchorage blew in March 2009, dropping ash during the medals ceremony for the U.S. alpine ski championships at Alyeska Resort in Girdwood. Some volcanoes erupt and spit out additional ash intermittently for weeks, as Bogoslof seems to be doing. The observatory uses mathematical models to forecast how fast ash particles will be transported in the atmosphere. Ash can scrape the moving parts of jet engines such as turbine blades. Ash on hot parts of a jet engine is potentially more dangerous, according to the observatory. The engines operate near the melting temperature of volcanic ash. "Ingestion of ash can clog fuel nozzles, combustor, and turbine parts causing surging, flame out, immediate loss of engine thrust, and engine failure," according to the observatory. Ash from Kasatochi Volcano in August 2008 blew all the way to Montana.

  • zachb4-har
    1/19/2017 - 02:52 p.m.

    Alaskan volcanoes erupt because they are in the range of the Ring of Fire which is a very popular chain of volcanoes.

  • pshea-dav
    1/20/2017 - 07:51 a.m.

    In response to "why do Alaskan volcanoes erupte so often ," I agree that that many volcanos are erupting in the ring of fire. One reason I agree is that Bogoslof volcano has sent up ash clouds that have reached as high as 35000 feet. Another reason is that all the volcanoes eruption's are in the ring of fire A third reason, airlines get exited when an ash cloud rises above 20,000 feet.The get stream can carry ash for hundreds of miles. Even though volcanoes can be dangerous , I think they would be magnificent to see far away

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