Alaskan volcanoes
The Alaska Peninsula and the Aleutian Islands have about 80 major volcanic centers that consist of one or more volcanoes. Recent violent eruptions have demonstrated that volcanic hazards do exist in some areas of Alaska, even though it is sparsely populated. Alaskan volcanoes have produced one or two eruptions per year since 1900. At least 20 catastrophic caldera-forming eruptions have occurred in the past 10,000 years; the awesome eruption of 1912 at Novarupta in the Katmai National Monument is the most recent. Scientists are particularly concerned about the volcanoes whose eruptions can affect the Cook Inlet region, where 60 percent of Alaska’s population lives.
Alaskan volcanoes.
EXPLANATION Volcano active during past 2,000 years Population center 100,000 to 350,000 ALASKA Wrangell Hayes Anchorage Spurr Redoubt Iliamna Akutan Novarupta Augustine Cook Inlet Trident Bogoslof Ukinrek Martin Mageik Kagamil Chiginagak Ugashik-Peulik Carlisle Emmons Lake Yantami Kiska Cerberus Fisher Dutton Aniakchak Veniaminof Little Sitkin Kasatochi Amukta Pyre Pavlof Isanotski Westdahl Shishaldin Makushin Gareloi Vsevidof Okmok Tanaga Korovin Cleveland Kanaga Great Sitkin Yunaska
Redoubt Volcano, Alaska, erupting on December 16, 1989. (Photograph by National Park Service.)
Redoubt Volcano.
Redoubt Volcano erupted for the fourth time this century on December 14, 1989. Following several days of strong explosive activity, a series of lava domes grew in Redoubt’s summit crater during the next four months. Most of the domes were destroyed by explosions or collapsed down the volcano’s north flank. Some of these events triggered small pyroclastic flows that melted snow and ice on the volcano to form lahars in Drift River Valley, which empties into Cook Inlet 35 kilometers away.
Ash produced by the eruptions severely affected air traffic enroute to Anchorage, Alaska’s largest city and a major hub of domestic and international commercial air traffic. Many domestic carriers suspended service to Alaska following major explosive events, and several international carriers temporarily rerouted flights around Alaska. On December 15, a jetliner enroute to Japan encountered an ash cloud while descending into Anchorage. The plane quickly lost power in all four engines and lost 4,000 meters in altitude before the pilots were able to restart the engines. The aircraft landed safely in Anchorage, but it sustained more than $80 million in damage.