Volcanoes/Mount Redoubt

The mushroom-shaped plume in the image on the right rose from avalanches of hot debris that cascaded down the north flank, when Mount Redoubt erupted on April 21, 1990.

"Redoubt Volcano is a steep-sided cone about 10 km in diameter at its base and with a volume of 30-35 cubic kilometers. The volcano is composed of intercalated pyroclastic deposits and lava flows and rests on Mesozoic granitic rocks of the Alaska-Aleutian Range batholith (Till and others, 1993; 1994). It has been moderately dissected by the action of numerous alpine glaciers. A 1.8-km-wide, ice-filled summit crater is breached on the north side by a northward-flowing glacier, informally known as the Drift Glacier, which spreads into a piedmont lobe in the upper Drift River Valley. The most recently active vent is located on the north side of the crater at the head of the Drift glacier. Holocene lahar deposits in the Crescent River and Drift River valleys extend downstream as far as Cook Inlet."

Eruptions
In the first image on the right, the view is looking "south at the north flank of Redoubt volcano. Ashfall [is] limited to south crater floor, rim, and extending south-southeast. Source of ash is a vent south of the 1990 dome at an elevation of ~8300 ft." This eruption occurred on March 15, 2009.

In the second image down on the right, Mount Redoubt erupts on April 4, 2009. The eruption started at approximately 6:00 a.m. The image was taken at 8:11 a.m. (ADT). The eruption sent ash more than 50,000 feet into the air.

The third image down on the right shows an eruption of Mt Redoubt on June 9, 2009, in Alaska: the lava dome in the summit crater is spilling over from the crater. Size of dome at time of this image is about 1000 m long, 450 m wide, and 200 m high.

Meltwaters
"On a summit flight, we were able to see the source of the meltwater stream. It appears to starts to the right of the dome where a fall face can be seen and continues down."

The image on the left shows flooding some 7.6 m deep caused by the melting of Drift Glacier.

Glaciers
"The [Ice Piston] glacier that filled the crater was collapsing because of the increase in ground temperature underneath."

Glaciers and snowfields appear to be numerous in this late spring image on the left of Mount Redoubt.

On the lower right is an image of the Drift Glacier area. The view is downstream to the northeast.

On the lower left is the Redoubt Glacier and below it is Ouzel Lake which the glacier drains into. The image is dated to August so the glacier has probably retreated from its winter advance maximum.

Recent history
The recent history period dates from around 1,000 b2k to present.

Redoubt Volcano, 3,108 m (10, 197 ft) high, is one of the active volcanoes of the Cook Inlet region. The breached summit crater is drained by Drift glacier, which empties into the Drift River valley forming a piedmont lobe. View is to the south on September 1, 1980.

Hypotheses

 * 1) Mount Redoubt has a VEI < 4.
 * 2) Mount Redoubt erupts to allow charge to escape through this conductor.