Featured Research

from universities, journals, and other organizations

Explosive Eruption Of Okmok Volcano In Alaska

Date:
July 21, 2008
Source:
United States Geological Survey
Summary:
Okmok Volcano in Alaska continues to produce explosions and ash plumes through a newly created vent and poses hazards to air travel in the area. Scientists are using a combination of seismic and GPS instruments on the ground and weather and radar satellites in space to track the progress of the eruption. Human visual observations are limited because airborne ash obscures a view of what is happening inside the volcano's 6-mile-diameter caldera and the area is too hazardous to enter.

Eruption of Okmok, image taken on Sunday, July 13, 2008.
Credit: Photo by Kelly Reeves; Image courtesy of Alaska Airlines

Okmok Volcano in Alaska continues to produce explosions and ash plumes through a newly created vent and poses hazards to air travel in the area.

Related Articles


Scientists are using a combination of seismic and GPS instruments on the ground and weather and radar satellites in space to track the progress of the eruption. Human visual observations are limited because airborne ash obscures a view of what is happening inside the volcano's 6-mile-diameter caldera and the area is too hazardous to enter.

"We are dealing with a scientific challenge because the volcano went from very quiet to a large eruption, putting ash to high altitudes with almost no warning," said John Power, Acting Scientist in Charge of the Alaska Volcano Observatory (AVO).

The powerful eruption in the Eastern Aleutian Islands began unexpectedly on July 12, sending up a wet, ash and gas-rich plume that reached an altitude of 50,000 ft above sea level. Heavy ash fall occurred on eastern Umnak Island. A dusting of ash fell in the busy fishing community of Unalaska, 65 miles northeast of Okmok volcano. The ash plume soon spanned several hundred miles across the North Pacific, causing many trans-Pacific flights to be diverted and cancellation of flights to the Dutch Harbor airport. The gas cloud from the eruption is now over Montana.

The eruption also destroyed or damaged seismic and deformation sensing equipment at two monitoring stations. A third station has lost its communication pathway due to destruction at the other two. Seismic equipment relays earthquake information and GPS equipment is used in monitoring the deformation of the ground surface in response to magma movement. Seven seismic stations are still operational and seismicity has gradually decreased in intensity since the initial eruption.

At a minimum, activity at Okmok is likely to continue for days or weeks. Strong gas-driven explosions can produce rock ballistics or larger volcanic debris that can be hurled beyond the crater rim of the volcanic caldera, potentially landing in surrounding areas several miles away. Fast moving clouds of ash, larger debris, and hot gas can form and flow across the caldera floor, rise up over the caldera wall and continue to flow down Okmok's flanks. Rain mixed with ash could create mudflows and rapid flooding along island drainages. As soon as conditions allow, AVO scientists will travel to the volcano in order to document and understand the sudden onset of explosive activity and repair damage to monitoring equipment.

The Okmok caldera formed during catastrophic eruptions 12,000 and 2,000 years ago. There are about a dozen cones within the modern caldera that formed in the last 2000 years, and the most recent eruptive activity occurred in 1945, 1958 and 1997. One violent eruption of Okmok in 1817 produced many feet of ash and "scoria" rock debris on the northeastern caldera rim, as well as ash fall on Unalaska Island and floods that buried an Aleut village at Cape Tanak on the northeast Bering Sea Coast of Umnak Island.


Story Source:

The above story is based on materials provided by United States Geological Survey. Note: Materials may be edited for content and length.


Cite This Page:

United States Geological Survey. "Explosive Eruption Of Okmok Volcano In Alaska." ScienceDaily. ScienceDaily, 21 July 2008. <www.sciencedaily.com/releases/2008/07/080720093810.htm>.
United States Geological Survey. (2008, July 21). Explosive Eruption Of Okmok Volcano In Alaska. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2008/07/080720093810.htm
United States Geological Survey. "Explosive Eruption Of Okmok Volcano In Alaska." ScienceDaily. www.sciencedaily.com/releases/2008/07/080720093810.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) — EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) — A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) — Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins