Redoubt Volcano - John Seach



60.485 N, 152.742 W
summit elevation 3108 m

Redoubt volcano is located in Lake Clark National Park. The summit contains a 1.8 km wide crater.

Redoubt Volcano is one of five volcanoes on upper Cook Inlet, Alaska. The volcano is located 120 km southwest of Anchorage, and has been the second most active volcano on the inlet during the past 10,000 years.

The volcano has a basal diameter of 10-12 km and a volume of approximately 40 cubic kilometers. Redoubt volcano is 100-110 km above the Benioff zone and 450 km northwest of the Aleutian trench.

The summit of the volcano contains a 1.5 km wide ice-filled crater. Two large glaciers extend from the crater. Drift glacier flows down a deeply incised valley on the north side. On the south side, a 1.5 km wide glacier flows down the large valley.

2010 Seismicity
A series of earthquakes began on 5th April 2010 near Redoubt's summit. Alaska Volcano Observatory raised the Volcano Alert Level to YELLOW.

2009 Eruption
Seismic activity increased markedly at Redoubt volcano between 23-25 January 2009. Tremor became sustained and its amplitude increased. Aviation Color Code was increased to ORANGE. A burst of volcanic tremor occurred at Redoubt volcano, Alaska on Thursday 5th February 2009 at 11:18 am (local time). The tremor lasted 4 minutes and was the most intense since January 30th. A second episode of volcanic tremor occurred just after 3:00 PM on Wednesday and lasted for about 30 minutes. No eruption accompanied the earthquakes.

An eruption occurred at Redoubt Volcano on 22nd March 2009, with ash emission to 50,000 ft above sea level. The volcano produced five explosive eruptions, each lasting from four to thirty minutes. Small amounts of ash fell at Skwentna, Talkeetna, Wasilla, and Trapper Creek. A large lahar occurred in the Drift River Valley and contained ice, water, mud, and other debris, and traveled more than 35 km to Cook Inlet. An eruption on 26th March ejected ash to a height of 65,000 ft. On 27th March ash reached 32,000 ft altitude. There were 11 large eruptions in the first week of activity with ash reaching altitudes of 30,000 to 60,000 ft.

2008 Volcano Unrest
Overflights of Redoubt volcano in Alaska have revealed new areas of fumaroles and steaming in September 2008. On September 16 2008, a pilot flying nearby reported a strong smell of hydrogen sulphide. The following week, residents of a cabin near Wadell Lake 25 km northeast of Redoubt volcano reported loud noises coming from the volcano. An overflight on 27th September 2008 showed several fractures and circular openings in the upper Drift glacier that had not been seen before. No abnormal seismic activity has been detected.

1989-90 Eruptions
Redoubt volcano woke after 23 years of dormancy, on 14th December 1989. The eruptions destroyed a lava dome and produced pyroclastic flows and lahars. Redoubt erupted explosively over 20 times between 14th December 1989 and 21st April, 1990. The eruption caused economic losses estimated at over $160 million making this the second most costly eruption in U.S. history.

Aircraft Encounter with ash during 1989 Eruption
On a flight from Amsterdam to Anchorage, Alaska, a new KLM 747-400 (only three months old with approximately 900 hr total flying time) encountered an ash plume from Redoubt volcano. All four engines ingested ash and flamed out. The crew successfully restarted the engines and landed safely at Anchorage. All four engines were replaced and many airplane systems also had to be repaired or replaced.

Redoubt Volcano Eruptions

2009, 1989-90, 1967-68, 1966-67, 1966, 1965?, 1933?, 1902, 1819?, 1778?