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Redoubt update, 4 April 2009 4 April 2009

Posted by admin in activity reports, Alaska, eruptions, natural hazards, Redoubt, United States.
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Thermal infrared image showing likely base of new lava dome, Redoubt Volcano (image creator Rick Wessels, image courtesy AVO/USGS).
Thermal infrared image showing the likely base of a new lava dome in the crater of Redoubt Volcano. While the dome is completely obscured by ash and steam in the visible photographs, the heat of the new lava can often be detected by the thermal infrared camera. The image also shows a trail of hot block and ash confined to the canyon below the summit (image creator Rick Wessels, image courtesy AVO/USGS). [source]

Redoubt, currently at Orange/Watch status (lowered from Red/Warning yesterday), appears to have settled into a period of lava dome building. Tasty thermal infrared images released by the Alaska Volcano Observatory indicate the probable location of the new dome (see above).

There have been no explosive eruptions since 30 March, but there have been constant emissions with varying ash content, and elevated seismicity consisting of an interesting pattern of regular small earthquakes. This latter behaviour has been going on since around 08:30 AKDT on 2 April; the Alaska Volcano Observatory describes it as a pattern of ‘small, shallow, repeating volcanic earthquakes’ and interprets them as being associated with lava dome growth. The pattern is particularly clear on the REF trace:

Redoubt REF Webicorder trace 3-4 April 2009 (AVO/USGS)

Lava dome extrusion is not a stable situation, indeed it is an inherently unstable one. Explosive or gravitational collapse of the dome could occur at any time, and if it does we will see the generation of further pyroclastic flows, ash clouds and lahars.

The latest from the AVO (2009-04-04 02:08:07) is that the intensity of ash production has decreased.

Other Redoubt news:

  • Redoubt has a new webcam, located at the DFR seismic station about 12 kilometres NE of the crater. This camera is set to capture an image every two hours.
  • The decision has finally been taken to remove some of the 6 million gallons of oil presently sitting in the Drift River Oil Terminal, patiently waiting for a lahar to unseat the tanks and send it all pouring into Cook Inlet. The plan is to transfer around 3 million gallons to a tanker over this weekend.

UPDATE: There’s been some explosive activity in the last couple of hours – see reports from vigilant commenters below. More on this later.

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 - 4 April 2009

Another pretty big eruption/explosion occurred a while ago! (13:57 GMT)
Too bad that the webcams are still in the dark.

2. SHIRAKAWA Akira - 4 April 2009

A bigger explosion blended with the preceding one, starting from about 14:14 UTC!

3. Stefan - 4 April 2009
4. gg - 4 April 2009

Bam! She’s code red again, with lovely images on the webicorder and a cloud to 50,000 feet. A lahar has formed. Will magma reach the Drift River Terminal? Etc.

5. gg - 4 April 2009

There’s a flash flood warning for the Drift River:

http://pafc.arh.noaa.gov/volcano.php

That’s the lahar in action.

6. volcanism - 4 April 2009

They were supposed to be shifting oil out of the Drift River terminal today. That may have to be delayed now …


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