Mount St.Helens (Official Alert Thread)

NA | October 7, 2004 | Mr. Atos

[Mr.Atos]

This is the Official News Thread for Mt. St. Helens Information.

(Please post all future updates, eyewitness account, news, and alerts to this thread.)

United States Geological Survey(USGS)

United States Geological Survey Cascades Volcano Observatory

LiveVolcano Cam from Johnston Ridge

Webicorders Current Seismic Activity (See St. Helens - South-Ridge)

KXL am 750 - Portland Live News Radio Stream

[Mr.Atos]

The ongoing activity has seems to have rendered a passive attitude towards a very dangerous situation. Free Republic has become a very important resource for real time information. Yet the extended nature of this event and the recent(seemingly) dimishing activity may have eased cautions regarding the volcanos dangerous potential. Per the USGS's recent assessments, activity could go on at this level for months. Or things could change catastrophically in an hour. For that reason I think that it is important to maintain one resource for all current information and links.

I hope that it proves to be useful.

As of 10:30am... Mt. St. Helens continues to change. The area behind the lava dome has risen 50 to 100 feet in the last few days. Geologists say that's caused by magma about 200 meters below the surface. They say the hot rock will continue to cause steam that'll vent from the crater. Several large steam plumes occured Thursday. The bulge is similar to something that occured in 1980, prior to the first eruption. However, the big difference is that bulge occured on a weak side of the mountain that gave way causing the massive eruption. They do not expect that to happen now. All road and trail closures remain in place.

[michigander]

eyewitness account:

All quiet here.

[WhistlingPastTheGraveyard]

The little volcano who burped "wolf!".

[Brett66]

[Siegfried]

Weather front is moving in this afternoon. Should have lots of rain on Mt St Helens tomorrow (maybe even causing local mud flows), and could have snow on Sat morning even down to 4500 feet, the same elevation as the viewing area at Coldwater Ridge.

[Darksheare]

There's some pics of the upfaulting rock.
The entire current lava dome has hot points under it, meaning that the entire volcanic neck has at least hot rock in it if not magma.

I'm afraid for the people living out that way.

[zygoat]

LOL! I expect THAT blowhard to erupt tommorow night!

[Mr.Atos]

[ValerieUSA]

The dome steamed and fussed and grew for more than a year after the 1980 eruption.

[Salvation]

Mount St. Helens' Crater Floor Rising

[Salvation]

Oregon Ping

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[blackie]

Be Ever Vigilant!

[momfirst]

mountain's way of saying "come closer, I won't hurt you".

I wasn't here for the 1980 even, but my co-worker said basically those exact words, reminiscing the time before May 18th. Until this Mt. is quiet for a few months straight, I'll be a little hesitant to rush up there and check it out.

[Clinging Bitterly]

It seems to me the mechanics are a little different this time around. It has been a relatively short time since it's last period of activity and the internal pressure is working against a thinner (and more level) crust of earth that seems to be readily yielding to the pressure from underneath.

In 1980 we had a bulge forming on the side of a steep peak, and there was a massive landslide and a sort of rapid decompression that contributed a fair amount to the degree of violence in that event.

I'm no vulcanologist, but judging from the shape of the peak before the eruption, I'd guess that what happened in 1980 was an especially violent eruption compared to that particular volcano's recent history.

Here, I think we're about to see some significant regrowth of the peak. There is evidence of steady movement in the column of magma within, but without a lot of resistance I think the discharge is not apt to be as violent as before and will probably remain largely within the crater. This will probably repeat itself over a period of time until, perhaps in another thousand years, we'll have a fully formed peak again. In my simplistic view, I imagine the changing weight and forces of the re-formed mountaintop affecting where pressure outlets are likely to appear and we'll again have the possibility of what happened in 1980, but not in our lifetimes.

Now there are certainly folks who know more about this than I do, and they might say I'm full of beans. I'm just looking at it from some 130 miles away and speculating based on my rudimentary knowledge of physics, but bottom line is right now I don't see how a real violent explosion would be possible. There is no great force holding against the internal pressure, hence there can't be an explosive release.

This is a unique opportunity to see some of the usually invisible forces that formed and still are forming the geologic features around us. The Cascade range is a wonderful part of the earth to live on or around. It is as rich in life and beauty as any place on earth, and with some thought we realize how much of what we have and enjoy in this region of the world is owed to those once and future fiery upwellings of the ever provident earth. We witness here the beauty of God's creation, that this seemingly destructive force ultimately gives us life.

[Mr.Atos]

Mount St. Helens Update, October 7, 2004, 6:15 p.m., PDT

Current status is Volcano Advisory (Alert Level 2); aviation color code ORANGE

Seismic activity has been at a low to moderate rate today, with earthquakes of magnitude 1 to 2 occurring at a rate of about 1 per minute. Visual observations of the vents and the area of intense uplift on the south side of the 1980-86 lava dome suggest that there has not been noticeable additional uplift in the past 24 hours. However, a new steam vent opened overnight to join the two that have been present for several days. Steaming from the vents generates a cloud that rises above the south side of the lava dome and extends a variable distance toward the crater rim.

Gas-sensing and thermal imaging flights are underway late this afternoon and results will be available later. Crews are also downloading GPS data and completing some work on seismic stations.

As a result of the intense unrest of the past 11 days, we infer that magma is at a very shallow level. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest and perhaps an eruption could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs. Therefore, we continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), combined with eruption models, show winds this evening will be westerly and any ash clouds will drift east-northeastward. By tomorrow morning the winds will shift more to the south and any ash will drift more northerly.

Press conferences will continue to be held at the Headquarters office of the Gifford Pinchot National Forest. The morning press conference is at 9:30 AM

ST HELENS PING LIST

[poindexter]

"the current calm is the mountain's way of saying "come closer, I won't hurt you". Just like in 1980."

In 1980, the mountain was going _nuts_. Parts of the entire _side_ of the mountain were bulging _feet_ per day. It was obvious to everyone that something very big was going to happen...and it did. This is just a prelude to a hiccup.

[Darksheare]

The volcanic pipe has also had a 1 kilometer solidified plug in it for a couple years, the magma coming up the pipe actually got there in 98 some time and has been slowly remelting the rock.
The current lava dome is 1000 feet tall, and roughly 2000 or 3000 feet wide.
And it's got heat coming through it visible.
I'm not sure of teh mechanics myself, but this is looking truly odd.
If it has highly gasified magma, it'll blow spectacularly regardless of how much rock is between it and the surface.
Hopefully it's the kind that has at least minimal gas dissolved in it.
(Gasified lava acts like a shaken soda bottle, the pressure releases and the gas exsolves from the lava, instantly doubling it's volume and blowing the heck up.)

At least, that's as far as I understood the explanation.

Either way, we'll get to see how this turns out.

[Mr.Atos]

And it's got heat coming through it visible.

I noticed that too watching the webcam for the last few days. The cauldera looks like a veritable sauce pot. The 'bulge' has grown in excess of 200 feet at this point, on the south side of the internal cone. We are all operating under the assumption that there will be no repeat of the 1980 cataclysm. And yet, do lets recall that the original eruption was preceded by a sizeable bulge growing on the mountain's north flank. But that bulge did not blow-up as much, as the mountain's entire slope calved off. The additional assumption is that all new activity will be shielded from the south and directed north. But, her rock structure is all torn up to be sure. A similar landslide on the south or southwest face, with the pressure that is building in her now, could be cataclysmic as well. This is speculation on my part, and others could offer further clarification. My geologic studies are limited to their archaeologic applications. But, the historic record is full of petrified corpses that underestimated old Vulcan. Extended caution is urged with this particular mistress.

The siemsic activity dimished overnight. But, it looks to have picked up again this morning. This begs the question for our resident geologists. Activity seems to occur in the morning, like she's keeping banker's hours. Are there magma tides oriented with the gravitational pull of the sun? (and perhaps even the moon?)

Atos