AVO reported that during February 25-March 3 seismic activity at Redoubt was variable. On 25 February, a small mud flow originating from a melt hole in the Drift Glacier traveled several hundred meters. Satellite images revealed that the next day another mudflow traveled several kilometers and covered a large portion of the Drift Glacier. Web camera views and satellite imagery showed no unusual activity; steam plumes within the summit crater were seen on the web camera on 26 and 1 March.

Geological Summary. Redoubt is a glacier-covered stratovolcano with a breached summit crater in Lake Clark National Park about 170 km SW of Anchorage. Next to Mount Spurr, Redoubt has been the most active Holocene volcano in the upper Cook Inlet. The volcano was constructed beginning about 890,000 years ago over Mesozoic granitic rocks of the Alaska-Aleutian Range batholith. Collapse of the summit 13,000-10,500 years ago produced a major debris avalanche that reached Cook Inlet. Holocene activity has included the emplacement of a large debris avalanche and clay-rich lahars that dammed Lake Crescent on the south side and reached Cook Inlet about 3,500 years ago. Eruptions during the past few centuries have affected only the Drift River drainage on the north. Historical eruptions have originated from a vent at the north end of the 1.8-km-wide breached summit crater. The 1989-90 eruption had severe economic impact on the Cook Inlet region and affected air traffic far beyond the volcano.

Source: US Geological Survey Alaska Volcano Observatory (AVO)