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Mount St. Helens Shoots Steam, Ash
Wynken de Word writes "Months after the preliminary signs starting showing, Washington State's Mount St. Helens is sending a plume of steam and ash 7,600 metres into the air as of Tuesday, 17:25 PST. See the U.S. Geological Survey site for more updates and, come daylight, check out the Mount St. Helens VolcanoCam."
These are andesitic volcanos, not tholiitic.
The lavas are viscous. Unless you are in the rim of the volcano or are flying over the ridge with an infrared camera you won't see lava from St. Helens.
"Rocky Rococo, at your cervix!"
NWCN site has a video the "Take a look inside the crater" http://www.nwcn.com/ link shows... well inside the crater. You have to sign up.
Probably aren't any yet. Any flow should have been confined to the crater and obscured by ash and steam. The event came just before local sunset. Things may be clearer in the morning.
The Mt. St. Helens webcam sometimes picks up the infared glow of exposed lava after dark. It went offline Friday, but service was fortunately restored this afternoon -- just hours before St. Helens burped. Check to see whatever can be seen here. My site also has some background on the webcam.
KPTV has some impressive stills of the ash plume here.
This is my post. There are many others like it. If you don't like what you read here, go try one of the others.
Close enough that they would have gotten a dusting of ash in 1980 (as did we in Portland, though I was too young to remember), but not close enough to do cover them in lava.
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I guess it would work better as a link.
Cascades Volcano Observatory
"We can't solve problems by using the same kind of thinking we used when we created them." -- Albert Einstein
http://vulcan.wr.usgs.gov/Volcanoes/MSH/Eruption04 /Monitoring/plume_in_the_evening_8march05.html
This has some pretty good photos, as well as a picture with (MS Paint?) editing describing what's what.
The photos are taken from a remote camera on the mountain that takes a picture every 2.5 minutes. This is as good as it gets.
That could be hot gas. Look up the words "nueé ardente".
Andesitic lavas have more water in them than tholiitic. That is why volcanos on or near continental margins explode violently and lavas from island chains only shoot ~30 meters into the air.
"Rocky Rococo, at your cervix!"
I live in Portland, Oregon, so I saw the eruption when it was taking place from my front porch.
It really wasn't very exciting. It was just a bunch of smoke and steam, around the size of several a few months ago.
Despite it being the sole story on the local news, nobody is going to die or even be injured. Nobody is going to care after tomorrow.
The volcano is regrowing a lava dome, and the dome is increasing in size. There's no visible lava, or anything more than the normal pickup truck worth of rock that's been added to the dome every second since October.
I don't get what the big deal is. It's a bit of smoke, that's all.
Months after the preliminary signs starting showing, Washington State's Mount St. Helens is sending a plume of steam and ash 7,600 metres into the air.
It's incorrect to imply, as the posting does, that the earlier activity is "preliminary", and that now the real action is going to get going. We are, in all likelihood, in a dome-building phase. It will have natural variation, times of activity and times of quiescence, just as the volcanic system has on a geologic time scale. There is no reason to expect a large explosive event in the near future.
-David Hirsch Asst. Professor of geology
What is interesting is that there was absolutely ZERO warning. There had been some minor tremors in the hours before, but nothing that would indicate something on this scale.
Personally, I think someone slipped the volcano some lima beans.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Keep in mind that Mt. Rainier is covered with glaciers and would cause massive mud slides if it erupted.
m /E MDiv/Mt%20Rainier%20VHRP.htm
http://www.co.pierce.wa.us/text/abtus/ourorg/de
In addition to producing tephra, magmatic eruptions of Mt. Rainier can produce lava flows or pyroclastic flows (fast-moving, hot, lethal avalanches of volcanic fragments and gas). The direct effects of such flows are to be expected on and near the steep flanks of Mt. Rainier, largely within the boundaries of Mt. Rainier National Park.
Much more far-reaching destruction can result from lahars that originate at Mt. Rainier. Deposits of at least 55 lahars within the last 10,000 years have been identified in the large valleys draining Mt. Rainier.
Lahars look and behave like flowing wet concrete owing to their characteristically high concentration of entrained sediment (commonly less than or equal to 60 volume percent). Because they are gravity flows, they become channeled into valleys. Led by a steep front charged with boulders, logs and any other available debris, they quickly fill pre-existing channels and spread across the adjacent flood plains, destroying mature forests and any human-made structures in their paths, including bridges, dams, roads, pipelines and buildings.
The depth and speed of a lahar depend on its size, its sediment concentration and the valley configuration. At Mt. Rainier, most of the large lahars are inferred to have traveled as fast as 50 miles/hr at depths of 100 ft or more in confined valleys and at a lower velocity and lesser depth in the wide, populated valleys of the Puget Lowland. For example, remnant valley-wall deposits indicate that the Electron lahar was approximately 50 ft deep in its passage through the mile-wide Puyallup valley 1 1/4 miles upstream from Orting. However, the Electron lahar was about 180 ft deep 6 miles farther upstream, where the main part of the canyon is only about 1/4 miles wide.
A critical implication from a hazard-mitigation standpoint is that a massive lahar from Mt. Rainier may occur without the kinds of warning usually associated with an impending eruption.
One much larger, post glacial, flank-collapse lahar has been identified. Known as the Osceola Mudflow, it occurred about 5,600 years ago and was between 10 and 20 times the volume of the Electron lahar. It originated as a massive collapse of Mt. Rainier's summit and upper northeast flank. The Osceola Mudflow filled valleys of the White River system north and northeast of Mt. Rainier, covered more than 80 sq. mi. of the Puget Lowland, and extended into Puget Sound from what are now the Puyallup and Duwamish River valleys. Considered as "worst-case" or "maximum lahar" (only one lahar of this size is known to have occurred in 10,000 years), lahars of this magnitude have been assigned a recurrence interval of 10,000 years.
50 miles??? PAH!!!
More like 500 miles.
Linkey 1
Linkey2
Geological records indicate that Yellowstone erupts 'calendar like' every 600,000 to 650,000 years. It last erupted 640,000 years ago. It could go any day!
At most, there's only 10,000 years left!!! RUN FOR YOUR LIVES!!!