Mount Redoubt Volcano

[AKDenise]

Hi all, I'm new to this forum, but not new to volcano-watching.

dgavin - I believe you'll find that much of the water stored in this area is embedded in alluvial till - deep sand and gravel deposits from receding glaciers. Hope that helps a little.

I have a question that someone here might be able to answer: The geologists mentioned "repeating earthquakes" that showed up at 23:52 3/28. I cannot find a reference as to what they mean, that is IF the scientists know. Does anyone here know what they are and what they signify?

BTW - the 1966 eruption lasted for 2 1/2 years and low frequency sound waves were picked up at seismographs outside Fairbanks.:surprised

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[geonuc]

Hi, welcome to BAUT.

The USGS has an article on repeating earthquakes, although focused on the San Andreas fault.

http://earthquake.usgs.gov/research/...eld/repeat.php

[Swift]

Also, someone got very brave and did a night flyby during this mornings eruption at 1am, and got some very cool lightning Photographs.

http://www.avo.alaska.edu/image.php?id=17288

That is a great picture!

[Swift]

From AVO:

2009-03-29 06:04:16
Seismicity has been at low levels in the past 2 hours.

Things seem quiet over the last several reports.

[Dave J]

It will be interesting to "see" the mountain again, I wonder what changes will have happened?
I'm guessing (no real volcano background, just an "enthusiast") that the open caldera glacier and a good portion of the Drift glacier could be gone, as with the 89-90 episode. Haven't seen any reports on the situation in the lower Drift River area, but with the altitude some of the blasts have attained, and some of the photos, it's possible the vent has grown to encompass some of the early small vents in the caldera/upper glacier, with major lahars and mudflows to Cook Inlet (so long as there's glacial ice to melt). The oil terminal area could be quite a (bigger) mess, but not reports thusfar of any oil in the Inlet. I wonder if there's been any significant flow down the Crystal River side?
The before and after shots should be amazing to see, whenever the weather clears.

[dgavin]

Just so I understand, you're comparing the Redoubt ash with that of St. Helen's because both are subduction-related volcanoes, yet the presence of micro particulates in the northern volcano's ash might indicate magma - groundwater interaction?

Yes, compared ash from similar processes. I would of liked some ash from Okmok or from Cleveland instead of St. Helen's. But there is no SEM of those samples I could find.

Although it's more then just the ash. There were at-least two VEI 5 eruptions that were mostly steam, with just a little ash, with the ash content increasing with each eruption. Thats not odd behavior, but the short duration of them, combined with the force of them indicates much more gas present then in normal subduction systems.

The only thing that seems to make sense is that some sort of magma/groundwater interaction is going on.

[dgavin]

Hi all, I'm new to this forum, but not new to volcano-watching.

dgavin - I believe you'll find that much of the water stored in this area is embedded in alluvial till - deep sand and gravel deposits from receding glaciers. Hope that helps a little.

Welcome to BAUT!

That helps a lot. Thats exactly the sort of environment that can hold a lot of ground water.

Thanks man, you saved me some hunting for that information.

The oil terminal area could be quite a (bigger) mess, but not reports thusfar of any oil in the Inlet. I wonder if there's been any significant flow down the Crystal River side?
The before and after shots should be amazing to see, whenever the weather clears.

I read something in one of the past status reports that the Drift River oil pipeline terminal had been shut down, Monday I think, and that it had been damaged a bit after the shut down from mud flows.

[AKDenise]

Hi, welcome to BAUT.

The USGS has an article on repeating earthquakes, although focused on the San Andreas fault.

http://earthquake.usgs.gov/research/...eld/repeat.php

thanks.

It's interesting that the conclusions vary some from those for volcanos.

Apparently, the significance for volcanos is still under study, but some say it represents "chugging" (not sure what that means).

There was another eruption at 11:20. Ash to 25,000 feet.

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[AKDenise]

More searching about "chugging" found:

The physical model for chugging involves a time-varying narrowing vent where gasses are released in a series of oscillations which appear to be harmonic but instead are modelled as short-term transients, or discrete pulses, suggestive of choked flow.

snipped from : Explosions and periodic tremor at Karymsky volcano, Kamchatka, Russia

and

A new description of chugging events using wavelet transform methods, appropriate for non-stationary signals, shows subtle changes in the waveforms relate to physical processes in the volcano. A system of non-linear feedback, based on choked flow at the vent, is postulated as the most likely source of this volcanic tremor.

snipped from: Non-linear explosion tremor at Sangay, Volcano, Ecuador

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[dgavin]

From my understanding with volcano's, "Chugging" is related to de-gassing events in the magma chimney or the magma chamber's.

Heck of a volcanic tremor going on right now, starting with the 11:20 event.

[jonfr]

There appears to be rather large magma movement under the volcano. It shows it self in the harmonic tremors on the webicorders.

I guess that next explosive event is going to happen in 3 to 10 hours time.

Spaceweather.com has a image showing the ash cloud movement over the past few days.

http://www.spaceweather.com/

[PetersCreek]

Fortunately, we only got a light dusting of ash here at the house in Peters Creek. Just a couple of quick snapshots of the hood of the wife's truck:


(Click for larger images)

There's a faint, flinty aroma of fireworks in the air. Other parts of the Anchorage area got the stronger sulphur smell.

[Dave J]

Earlier today, there were times on the seismic charts where there are little spikes, very regular, about every 30 second or so, for a good 30-45 minutes. Little, small, "puffs". Are these the "chugging" you all are discussing?

Real peculiar, as regular as they are...

[dgavin]

If you mean the ones from just before midnight to about 130am, yes thats the Chugging signature

[jonfr]

If you mean the ones from just before midnight to about 130am, yes thats the Chugging signature

What is a chugging signature exactly ? I am unfamiliar with this term. I found little on this on the internet. What I found was something about degassing of the magma, or something in that nature.

[hhEb09'1]

Nice photos, Brett. I immediately recognized the second one as an attempt to replicate the BAUT flag:

[AKDenise]

Earlier today, there were times on the seismic charts where there are little spikes, very regular, about every 30 second or so, for a good 30-45 minutes. Little, small, "puffs". Are these the "chugging" you all are discussing?

Real peculiar, as regular as they are...

It was 3/28 at 23:52.

When I first saw them, I thought it was a machine glitch, until the geologists made mention below:

2009-03-29 01:25:21

The repeating earthquakes that started at 23:52 AKDT have ceased.

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


other sources call the "small repeating earthquakes" in volcanos - "chugging".

[AKDenise]

On the pbs program tonight - "Kilauea", the geophysicist recording the "sounds" a volcano makes, also used the term "chugging."

He also discussed "infrasound", the extra low frequency sounds given off by volcanos. In the 1965 Redoubt explosion, some infrasound was heard as far away as College -near Fairbanks.

Program site:
http://www.pbs.org/wnet/nature/episo...oduction/4718/

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[jlhredshift]

Now the volcanoes are talking to each other:

2009-03-30 02:16:26

We are re-analyzing the event reported as an explosive eruption occurring at approximately 23:14 AKDT (7:14 UTC). An episode of stronger tremor at the volcano was in progress when the seismic signal from a M5.4 earthquake near Kodiak Island passed through the Redoubt area causing the tremor amplitude to appear to increase quickly.

Radar did show a cloud top above 20,000 ft above sea level at approximately the same time.

[jonfr]

@ 07:13:05.5 UTC 30 Mars 2009 there was a Mw6.0 earthquake in the nearby area. That is not good news for the volcano. As this type of earthquake can have effect on the eruption. More info on the earthquake here.

[dgavin]

Now the volcanoes are talking to each other:

USGS classified this as a non explosive out gassing event, they are not saying if it was possibly triggered by the Mag 5.4 quake near Kodiak Island, or just a coincidence.

I would say it was likely a triggered event, but this also is a good sign in a way. If a quake 590km away can trigger a small out gassing, then it means the volcano's chimney is fairly clear.

Thats also not surprising after a dozen+ eruptions in one week.

The real question is, will there be any more hydrothermally assisted explosive eruptions?

[One Skunk Todd]

The hut cam is a bit gunked up but it "looks" like there is dark smoke/ash coming out right now. Not sure if dark smoke = eruption.

http://www.avo.alaska.edu/webcam/Redoubt_-_Hut.php

[jonfr]

There appears to be a lot of ash in that picture. Along with some changes in the volcano it self.

Mount Redoubt has blow off it's top in some older eruption. However, that does not exclude a caldera formation event.

[confuseatron]

From the AVO hut cam, this frame seems to have a little orange spray. Lava, or light filtering through ash, maybe? Dome leaking?

Kinda scary if its coming out somewhere else than the caldera.. afraid the side of Redoubt will fall off and it will do a Mt St Helens right into the nice webcam...

[jlhredshift]

2009-03-30 16:39:48

Webcam views show a steam-rich plume that may still contain some ash. Seismicity has diminished with a only a few small discrete events observed over the last hour. An AVO gas flight has returned.

Anyone want to volunteer to go on those flights?

As Donkey would say (Shrek) :

"Me, Me, Pick Me!"

[flynjack1]

Heck I was spooked just flying over Mt Vesuvius 2000 years after the fact. They would have to pay me well and give me something faster than a helicopter. Im not sure how fast the dust cloud from an errupting volcano spreads but I would guess it could be in excess of 110 knots (the speed of most helicopters at altitude).

[Dave J]

From the AVO hut cam, this frame seems to have a little orange spray. Lava, or light filtering through ash, maybe? Dome leaking?

Kinda scary if its coming out somewhere else than the caldera.. afraid the side of Redoubt will fall off and it will do a Mt St Helens right into the nice webcam...

That might be a small pyroclastic flow, just below where a dome might be forming, see some smoke there nearby...real good for melting glacial ice.
I'd be curious as to how many domes have been started, then blown away/collapsed, in the last week.
I think I saw them around a Piper Navajo in some pics...nice and fast for quick bug-outs.

[dgavin]

To add to DaveJ's reply.

I checked the cam at night and there is no indication of glowing magma, yet, so likely it was a pyroclastic event.

[AKDenise]

AVO just posted some more photos from their overflight today. Great shots of steam, more steam, etc.....but that's what it's been today - steam plume with small amount of ash. One photo looks right into the crater.....no lava.

Best of all is the EM shots of the crystals. Did a little reading. One source says the resultant crystal is proof of convection within magma chambers. More sources discuss the different results from water with magma. Someone with more knowledge of chemistry must decipher these articles.

Regarding the earthquakes near Kodiak. Remember all the other volcanoes in the vicinity - Augustine, Novarupta/Katmai (very bad 1912 eruption), Spurr, etc. The earthquakes are in the beginning, upper layer of the subduction zone, so.....you could speculate that if the magma in the ending lower areas of the subduction zone, is being evacuated to the surface, it could be influencing what happens in the upper areas of the crust that would be plunging at a 45 degree angle to the area below the volcanos.

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[geonuc]

Anyone want to volunteer to go on those flights?

As Donkey would say (Shrek) :

"Me, Me, Pick Me!"

I'll go, even if Donkey comes along.