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| Alaska's Mt. Redoubt volcano |
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Alaska is home to more than 40 active volcanoes (volcanoes that have had at least one eruption since 1760) and many more potentially active volcanoes. Many of Alaska's volcanoes occur along the Alaska Peninsula and Aleutian Island. They are part of what is called the "Ring the Fire" that surrounds much of the Pacific Ocean.
What is a Volcano?
Volcanoes are cracks or ruptures in the earth's crust through which molten (melted) rock, ash and gases rise to the surface.
There are different types of volcanoes. Cinder cones are usually short with steep slopes, and are formed by explosive eruptions of pumice, ash, and other debris. Shield volcanoes are wide and slightly flat. They are formed by successive flows of lava, usually over a long period of time. Stratovolcanoes can be tall and cone shaped, and are formed by a series of eruptions; some with lava, and some with mostly ash.
Alaska's Volcanoes
Alaska boasts the planet's largest eruption in the last century: the 1912 eruption of Novarupta, 450 miles southwest of Anchorage in what is now Katmai National Park. The eruption occurred over a 60-hour period. It darkened the sky over much of the Northern Hemisphere for several days, and deposited a foot of ash on Kodiak Island, 100 miles away. When the eruption was finally over, more than 40 sq. miles of once lush, green land were buried under volcanic deposits as deep as 700 feet. Many small holes and cracks developed in the ash fall, which let gas and steam escape from heated ground below escape. The result was a landscape riddled by thousands of steam vents. When explorer Robert Griggs came to see the damage of the eruption in 1916, he was amazed at what he saw and named the area "The Valley of Ten Thousand Smokes." Today, the steam vents are gone, and the valley continues to recover. Visitors to the area can still see evidence of the eruption and are reminded of the awesome power and destruction volcanoes can unleash.
Pavlof volcano is one of the Alaska's most active volcanoes, with 41 eruptions reported since 1760. Pavlof erupted in 1986 and ash was sent 10 miles into the sky, causing black snow to fall on Cold Bay. Another recent eruption occurred in 1992, When Mt. Spurr sent ash and debris into the air and stopped air traffic in and out of Anchorage for several days.
For more specific information about Alaskan volcanoes, visit the Alaska Volcano Observatory website at
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