60°29’N 152°44’W 60°29’N 152°44’W 177 km SW of Anchorage 177 km SW of Anchorage few hundred kilometers from ½ of Alaska’s population) few hundred kilometers from ½ of Alaska’s population)

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

Steep-sided, heavily-glaciated stratovolcano Lava dome in summit crater Contains active steam vents and fumaroles Contains active steam vents and fumaroles Drift Glacier 3108 meters (10,197 feet) above sea level 3108 meters (10,197 feet) above sea level 10 km diameter at base 10 km diameter at base km 3 volume km 3 volume

1778… Captain James Cook observed Redoubt “emitting a white smoke but no fire” 1778… Captain James Cook observed Redoubt “emitting a white smoke but no fire” 1902… Oldest historic eruption 1902… Oldest historic eruption … 11 eruptions … 11 eruptions … 23 “major explosive events” … 23 “major explosive events” 2009… 19 “major ash producing explosions” 2009… 19 “major ash producing explosions”

October 1989 – December 2010 – 10,400+ earthquakes within 12.5 km of summit Largest earthquake recorded: – Magnitude 3.5 4/9/09

Large explosions with volcanic ash Large explosions with volcanic ash Lava dome growth Lava dome growth Repetitious dome Repetitious dome failure, high altitude ash plumes, and pyroclastic flows Lahars and flooding Lahars and flooding

Economic losses Economic losses >$169 million Jet aircraft’s engines Jet aircraft’s engines Drift river Oil Terminal Drift river Oil Terminal Cook Inlet oil production Cook Inlet oil production Drift Glacier Drift Glacier

Six months - Pre-eruptive seismic unrest Six months - Pre-eruptive seismic unrest July Strong sulfur smell July Strong sulfur smell March 22 nd - First magmatic explosion with ash column March 22 nd - First magmatic explosion with ash column – 19 major ash-producing events – Pyroclastic flows – Lava domes April 4 th - July 1 st – Final dome building April 4 th - July 1 st – Final dome building

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

Rocks ( % SiO 2) Rocks ( % SiO 2) – basalt to basaltic andesite lava flows – scoria deposits – andesitic ash flow deposits – accretionary lapilli – dense glacial ice clasts Products of 2009 Eruption Andesitic ( % SiO 2 ) lava and tephra Andesitic ( % SiO 2 ) lava and tephra plagioclase plagioclase orthoclase orthoclase clinopyroxenes, clinopyroxenes, amphiboles amphiboles iron-titanium oxides iron-titanium oxides

2009 Satellites Satellites Web cameras Web cameras Seismic monitoring Seismic monitoring Volcanic gas measurement Volcanic gas measurement Volcanogenic lightning detection Volcanogenic lightning detection Infrasound Infrasound Radars RadarsToday 9 station seismic network 9 station seismic network GPS receivers GPS receivers 5-10 seismometers 5-10 seismometers

Tourism – Some recreational activity Geothermal energy – None Hydrothermal activity – None

Volcanic ash clouds Volcanic ash clouds Volcanic ash fallout Volcanic ash fallout Lahars and floods Lahars and floods Pyroclastic flows and surges Pyroclastic flows and surges Debris avalanches Debris avalanches

Alaska Volcano Observatory, 2015: Redoubt: Current Activity, at (accessed 24 January, 2015) (accessed 24 January, 2015) Alaska Volcano Observatory, 2014: Redoubt Volcano description and information, at (accessed 24 January, 2015) (accessed 24 January, 2015) Ball, Jessica, 2009: Redoubt Volcano – Alaska, at (accessed 24 (accessed 24http://geology.com/volcanoes/redoubt/ (accessed 24 January 2015 January 2015 Bryson, George, 2009: Fifth explosion rocks Mount Redoubt volcano, (accessed 24 January, 2015) (accessed 24 January, 2015) Chouet, Bernard, 2002: Volcanoes Talking, at (accessed 26 January, 2015) Fisher, Richard, 1997: Volcanoes: Crucibles of Change. Princeton, New Jersey: Princeton University Press; pp.

Hemming, Bryan, 2009: The Road, at erupts.htm (accessed 25 January, 2015) erupts.htm (accessed 25 January, 2015) National Park Service, 2015: Introducing Lake Clark’s Volcanoes, at volcanoes.htm (accessed 24 January, 2015) volcanoes.htm (accessed 24 January, 2015) Oregon State University, 1984: Redoubt, at (accessed 24 (accessed 24http://volcano.oregonstate.edu/redoubt (accessed 24 January, 2015) January, 2015) Power, John, 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 – and a conceptual model of the Redoubt magmatic system. Journal of Volcanology and Geothermal Research, vol. 259, pp 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 ; 1-38 p.