Redoubt Volcano Alaska, USA

Mollie Taylor and Ilana Zyatitsky

Department of Geology, Colby College Professor Robert Nelson – Jan Plan 2015

Geographic Setting

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60°29’N 152°44’W 177 km SW of Anchorage

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few hundred kilometers from ½ of Alaska’s population)

Tectonic Setting

Formation History

880,000 y.a.

Early explosive stage 340,000 and 184,000 y.a.

Early cone-building stage 184,000 to 10,000 y.a.

Late cone-building stage 10,000 years ago to recent Post-glacial (Holocene) stage

Characteristics and Dimensions

Steep-sided, heavily-glaciated stratovolcano Lava dome in summit crater

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Contains active steam vents and fumaroles Drift Glacier

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3108 meters (10,197 feet) above sea level 10 km diameter at base 30-35 km 3 volume

Eruptive History

• • • • • 1778… Captain James Cook observed Redoubt

“emitting a white smoke but no fire”

1902… Oldest historic eruption 1966-68… 11 eruptions 1989-90… 23 “major explosive events” 2009… 19 “major ash producing explosions”

Seismic History

October 1989 – December 2010

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10,400+ earthquakes within 12.5 km of summit Largest earthquake recorded:

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Magnitude 3.5 4/9/09

December 1989 – April 1990

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Large explosions with volcanic ash

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Lava dome growth

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Repetitious dome failure, high altitude ash plumes, and pyroclastic flows

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Lahars and flooding

Some Effects of the 1989-90 Eruptions

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Economic losses >$169 million

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Jet aircraft’s engines

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Drift river Oil Terminal Cook Inlet oil production

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Drift Glacier

March 2009 – April 2009

• • • • Six months - Pre-eruptive seismic unrest July 2008 - Strong sulfur smell

March 22 nd

ash column - First magmatic explosion with – 19 major ash-producing events – Pyroclastic flows – Lava domes

April 4 th - July 1

st – Final dome building

Some Effects of the 2009 Eruptions

• • • • •

Airports, schools, and businesses affected Ashfall affected ~80,000km 3 Removal of 6,000,000 gallons of crude oil Cook Inlet oil production Drift Glacier

Rocks and Deposits

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Rocks (53.1-68.5% SiO 2)

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basalt to basaltic andesite lava flows

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scoria deposits andesitic ash flow deposits

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accretionary lapilli dense glacial ice clasts

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Products of 2009 Eruption Andesitic (57.5-62.5% SiO 2 ) lava and tephra

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plagioclase orthoclase

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clinopyroxenes,

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amphiboles iron-titanium oxides

Active Monitoring

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2009 Satellites Web cameras Seismic monitoring Volcanic gas measurement Volcanogenic lightning detection Infrasound Radars

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Today 9 station seismic network GPS receivers 5-10 seismometers

Other Pertinent Info?

Tourism

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Some recreational activity Geothermal energy

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None Hydrothermal activity

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None

Future Hazards?

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Volcanic ash clouds Volcanic ash fallout

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Lahars and floods Pyroclastic flows and surges Debris avalanches

1989 and 2009 precursors

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Increased gas emission

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heat flux

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snow melt in summit crater

Bibliography

Alaska Volcano Observatory, 2015: Redoubt: Current Activity, at http://www.avo.alaska.edu/activity/Redoubt.php (accessed 24 January, 2015) Alaska Volcano Observatory, 2014: Redoubt Volcano description and information, at http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Redoubt (accessed 24 January, 2015) Ball, Jessica, 2009: Redoubt Volcano – Alaska, at http://geology.com/volcanoes/redoubt/ (accessed 24 January 2015 Bryson, George, 2009: Fifth explosion rocks Mount Redoubt volcano, http://www.adn.com/article/20090322/fifth-explosion-rocks-mount-redoubt-volcano (accessed 24 January, 2015) Chouet, Bernard, 2002: Volcanoes Talking, at http://www.pbs.org/wgbh/nova/volcano/ chouet.html

(accessed 26 January, 2015) Fisher, Richard, 1997: Volcanoes: Crucibles of Change. Princeton, New Jersey: Princeton University Press; 153 155 pp.

Bibliography (cont.)

Hemming, Bryan, 2009: The Road, at http://theroadcartoons.blogspot.com/2009/03/mount-redoubt erupts.htm (accessed 25 January, 2015) National Park Service, 2015: Introducing Lake Clark’s Volcanoes, at http://www.nps.gov/lacl/naturescience/ volcanoes.htm (accessed 24 January, 2015) Oregon State University, 1984: Redoubt, at http://volcano.oregonstate.edu/redoubt (accessed 24 January, 2015) Power, John, 2011. The 2009 Eruption of Redoubt Volcano, Alaska. Fairbanks, Alaska: Alaska Division of Geological & Geophysical Surveys; Report of Investigations #5.

Power, John, S.D. Stihler, B.A. Chouet, M.M. Haney and D.M. Ketner, 2011: Seismic observations of Redoubt Volcano, Alaska – 1989-2010 and a conceptual model of the Redoubt magmatic system. Journal of Volcanology and Geothermal Research, vol. 259, pp. 31-44. The Alaska Range Project, 2013: Where the peaks have no name, at thealaskarange.com (accessed 27 January 2015) Waythomas, Christopher F., Joseph M. Dorava, Thomas P. Miller, Christina A. Neal, and Robert G. McGimsey, 1998: Preliminary Volcano-Hazard Assessment for Redoubt Volcano, Alaska 97-857; 1-38 p.