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Alert level raised at Redoubt 22 March 2009

Posted by admin in activity reports, Alaska, Redoubt, United States.
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UPDATE: Redoubt erupted at 22:36 local time on 22 March 2009 – Redoubt erupts.

Seismic activity is increasing at Mount Redoubt, reports the Alaska Volcano Observatory, and the alert level has been raised again to Aviation Colour Code Orange, Volcano Alert Level Watch. A 300-metre (1000 ft) steam plume has been visible above the summit via the Hut webcam. As we reported here yesterday, the frequency and amplitude of discrete earthquakes have been increasing since around 10:00 local time on 20 March. That increase has become much more marked over the last 10-12 hours, as the RSO Webicorder trace shows:

Redoubt RSO webicorder trace 21 March 2009 (Alaska Volcano Observatory)

There is no sign of volcanic tremor: these are small, discrete quakes, currently occurring at a rate of several per minute. Furthermore, the AVO reports that these quakes are ‘shallow’ in depth – although there is no indication how shallow, or whether they are becoming shallower with the passage of time, which would indicate magma ascending the conduit.

In a status report issued at 13:23 local time (21:23 GMT) yesterday, the AVO reported that ‘Shallow earthquake activity under the volcano that began yesterday continues’, and that ‘A steam plume rising as high as approximately a thousand feet above the volcano is visible on the web cameras, but no explosive or ash activity such as occurred last Sunday has been identified’. At 22:09 local time yesterday (06:09 GMT 22 March 2009) a Volcanic Activity Notice was issued upgrading the alert status to Orange/Watch and stating: ‘AVO is raising the aviation color code to Orange and the alert level to Watch. Seismic activity has continued to increase and conditions may evolve rapidly culminating in an eruption within days to weeks’.

At the time of posting the latest AVO observations (2009-03-22 04:53:43) read: ‘Seismicity remains elevated with several small events occurring each minute. We are watching closely. There are numerous small events and size of the events has increased a bit’.

UPDATE: Check out Akira Shirakawa’s video of yesterday’s activity at Redoubt – some vigorous steaming captured by the Hut webcam.

UPDATE: The latest observations from the AVO (2009-03-22 08:45:06) – ‘Seismicity rates have increased dramatically over the last 48 hours. Currently, the earthquake rate is about 40 to 50 events per hour. Many of these events are large enough to be recorded at the more distal stations of the Redoubt network, including NCT and DFR’.

For all our Redoubt coverage: Redoubt « The Volcanism Blog.

Information
Global Volcanism Program: Redoubt – summary information for Redoubt (1103-03-)
Alaska Volcano Observatory – Redoubt – AVO information and updates for Redoubt
Alaska Volcano Observatory – main page for the AVO

The Volcanism Blog

Comments

1. SHIRAKAWA Akira - 22 March 2009

This is a video from I made from yesterday’s footage of Redoubt from the Hut webcam. To keep it short, this time it’s got no sound. Playing speed is 800x of realtime (about 12 hours of time compressed in 1 minute). At times, dense steam can be clearly seen emitting from multiple vents on the summit of the volcano:

2. theroachman - 23 March 2009

Just in from AVO

Over the last hour, the rate of seismic events has increased to the highest levels seen within the last 48 hours. We are watching the events closely and continue to staff the observatory 24 hours per day. The webcam view is still obscured by clouds.

3. Benjamin - 23 March 2009

Just went color Code Red. Website is very slow!

4. Wade - 23 March 2009

Wade from Anchorage here.

Mt. Redoubt has erupted at 22:38 Alaska standard time on 3/22. Initial ash cloud is estimated to be at 20,000 feet. Currently that would have the ash cloud skirting to the west of Anchorage, but if it reaches 40,000 feet it may hit Anchorage.

Stay tuned!

5. Benjamin - 23 March 2009

2009-03-22 23:02:22
An eruption of Mt. Redoubt began at approximately 22:38 AKDT, March 22, 2009 (0638 UTC). AVO is raising the aviation color code to Red and the alert level to Warning. Initial height of the eruption cloud is estimated at less than 20,000 ft above sea level at present. Further reports will be issued as more information becomes available.

6. boris behncke - 23 March 2009

as of 07h UT on 23 March 2009, Redoubt is erupting

7. Wade - 23 March 2009

Update: Ash cloud has reached 50,000 feet. Looks like a big one.

8. Mic22 - 23 March 2009

2009-03-22 23:20:21
Current estimate for eruption cloud height are 50,000 ft above sea level.

2009-03-22 23:05:18
An eruption is occurring. We will post more information as we interpret the data.

2009-03-22 23:02:22
An eruption of Mt. Redoubt began at approximately 22:38 AKDT, March 22, 2009 (0638 UTC). AVO is raising the aviation color code to Red and the alert level to Warning. Initial height of the eruption cloud is estimated at less than 20,000 ft above sea level at present. Further reports will be issued as more information becomes available.

9. Stefan - 23 March 2009

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