Redoubt back to sleep Options

[Sagebrusher]

The swarm of shallow, small earthquakes that began last Sunday, December 27 at Redoubt Volcano has greatly diminished or ceased. Close-in aerial observations of the new lava dome yesterday indicated no disruption at the surface and no sign of instability. Photographs and thermal camera imaging of the 2009 lava dome showed continued high temperature areas on the surface of the dome which is expected as the thick pile of blocky lava slowly cools in place. Magmatic gas emission from the dome area, however, is somewhat elevated compared to the last measurement in early November.

The Aviation Color Code remains YELLOW and the Volcano Alert Level remains ADVISORY.

AVO is continuing to evaluate information to interpret this week's uptick in seismicity and gas output. One explanation involves input of new magma or remobilization of existing magma within volcano's shallow plumbing system. This process appears to have ceased or paused. It remains possible that activity could reappear, intensify and lead to additional eruptive activity. We would expect a sharp increase in seismicity and other marked changes prior to such activity.

AVO will continue to issue daily status reports as long as the Aviation Color Code and Alert Level are elevated.




http://www.avo.alaska.edu/activity/Redoubt.php

This post has been edited by Sagebrusher: Jan 8 2010, 11:25 AM

[Sagebrusher]

AVO/USGS Volcanic Activity Notice

Volcano: Redoubt (CAVW #1103-03-)

Current Volcano Alert Level: NORMAL

Current Aviation Color Code: GREEN

Issued: Tuesday, January 5, 2010, 3:32 PM AKST (20100106/0032Z)
Source: Alaska Volcano Observatory
Notice Number: 2010/A1
Location: N 60 deg 29 min W 152 deg 44 min
Elevation: 10197 ft (3108 m)
Area: Cook Inlet-South Central Alaska

Volcanic Activity Summary: Based on the low level of seismic activity and lack of any obvious outward signs of progressing unrest, AVO is lowering the Aviation Color Code and Volcano Alert Level at Redoubt Volcano to GREEN/NORMAL.

The swarm of small, shallow earthquakes that began Sunday, December 27 has ceased and the degree of seismic activity beneath the volcano has returned to background levels. Aerial observations of the new lava dome on December 31 indicated no obvious changes at the surface and no sign of instability. Thermal images also obtained on December 31 indicate that parts of the dome are still hot, although most of the dome surface remains cold and snow covered. Magmatic gas emission from the dome area on December 31 was slightly elevated compared to the last measurement in early November, but not enough to warrant great concern.

It is likely that existing magma within the volcano's shallow plumbing system was temporarily remobilized, causing the increase in seismicity, but this process appears to have ended. It is possible for activity to resume at any time and if it does, we expect to observe a distinct increase in seismicity as well as other outward signs of unrest such as increased melting and steaming in the vicinity of the lava dome or rock fall activity on the slopes of the dome.

Recent Observations:
[Volcanic cloud height] Unknown
[Other volcanic cloud information] Unknown

Remarks: AVO will continue to monitor conditions at Redoubt, but while we have no volcanoes at elevated color codes or alert levels, we will cease our usual daily reporting of activity and instead transmit a weekly summary only.

Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, 1989-90, and 2009. The 1989-90 and 2009 eruptions produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 and 2009 eruptions significantly disrupted air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other communities in south-central and interior Alaska.