The questions below are ones that we frequently receive from people interested in Alaska's volcanoes. Since some of these questions are
answered by information in this website (and other websites), we've provided links for you to follow to learn of the answer(s).
Alaska contains over 130 volcanoes and volcanic fields which have been active within the last two million years.These volcanoes are catalogued on our website: http://www.avo.alaska.edu/volcanoes/
Of these volcanoes, about 90 have been active within the last 10,000 years (and might be expected to erupt again), and more than 50 have been active within historical time (since about 1760, for Alaska).
The volcanoes in Alaska make up well over three-quarters of U.S. volcanoes that have erupted in the last two hundred years.
Alaska's volcanoes are potentially hazardous to passenger and freight aircraft as jet engines sometimes fail after ingesting volcanic ash. On December 15, 1989, a Boeing 747 flying 240 kilometers (150 miles) northeast of Anchorage encountered an ash cloud erupted from Redoubt Volcano and lost power in all four jet engines. The plane, with 231 passengers aboard, lost more than 3,000 meters (~9,800 feet) of elevation before the flight crew was able to restart the engines (Casadevall, 1994). After landing, it was determined the airplane had suffered about $80 million in damage (Brantley, 1990).
We estimate, based on information provided by the Federal Aviation Administration, that more than 80,000 large aircraft per year, and 30,000 people per day, are in the skies over and potentially downwind of Aleutian volcanoes, mostly on the heavily traveled great-circle routes between Europe, North America, and Asia. Volcanic eruptions from Cook Inlet volcanoes (Spurr, Redoubt, Iliamna, and Augustine) can have severe impacts, as these volcanoes are nearest to Anchorage, Alaska's largest population center.
The series of 1989-1990 eruptions from Mt. Redoubt were the second most costly in the history of the United States, and had significant impact on the aviation and oil industries, as well as the people of the Kenai Peninsula. On the Kenai Peninsula, during periods of continuous ash fallout, schools were closed and some individuals experienced respiratory problems. At the Drift River oil terminal, lahars and lahar run-out flows threatened the facility and partially inundated the terminal on January 2, 1990 (Waythomas and others, 1998). The Redoubt eruption also damaged five commercial jetliners, and caused several days worth of airport closures and airline cancellations in Anchorage and on the Kenai Peninsula (Casadevall, 1994). Drifting ash clouds disrupted air traffic as far away as Texas. More information about the Redoubt 1989-1990 eruptions, including impact to people and infrastructure, is available here
The three eruptions of Mt. Spurr's Crater Peak in 1992 deposited ash on Anchorage and surrounding communities, closed airports, made ground transportation difficult, and disrupted air traffic as far east as Cleveland, Ohio. More information about this eruption is available here
. Many older Alaskans also remember ash falling on Anchorage during the 1953 eruption of Mt. Spurr's Crater Peak
The 1912 eruption of Novarupta and Katmai, which formed the Valley of Ten Thousand Smokes on the Alaska Peninsula, was the largest 20th-century eruption on earth, and the largest historical eruption in Alaska. Ash from Novarupta spread worldwide, and is often still remobilized by strong winds. Roofs in Kodiak collapsed due to the weight of the ash; six villages close to Katmai and Novarupta were permanently abandoned. More information about this eruption is available here
Information on older volcanoes previously listed by AVO, and Alaskan mountains that have erroneous eruption reports can be found here