Mount Saint Helens Releases Large Ash Plume

[HURAKAN]

Large Plume Billows From Mount St. Helens

VANCOUVER, Wash. -- Mount St. Helens released a towering plume of ash on Tuesday.

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The plume was accompanied by an earthquake of about 2.0 magnitude.

The volcano has vented ash and steam since last fall, when thousands of small earthquakes marked a seismic reawakening of the 9,677-foot mountain.

Late afternoon television footage showed the plume billowing thousands of feet into the air, then drifting slowly to the northeast.

The ash explosion happened around 5:25 p.m., about an hour after a 2.0 magnitude quake rumbled on the east side of the mountain, said Bill Steele, coordinator of the Pacific Northwest Seismograph Network at the University of Washington.

Steele said he did not believe the explosion had increased the risk of a significant eruption and noted that recent flights over the volcano's crater did not reveal high levels of gases.

Steele said the ash burst may have been triggered by partial collapse of a lava dome in the crater, which has been growing steadily over the last several months.

"Until we get a better view in the crater we won't know," Steele said.

Davis said there had been no increase in quake activity before the explosion.

"The seismicity had been continuing just as it had been," she said.

On May 18, 1980, the volcano 100 miles south of Seattle blew its top, killing 57 people and covered the region with gritty ash.

Mount St. Helens rumbled back to life Sept. 23, with shuddering seismic activity that peaked above magnitude 3 as hot magma broke through rocks in its path. Molten rock reached the surface Oct. 11, marking resumption of dome-building activity that had stopped in 1986.

A more explosive eruption, possibly dropping ash within a 10-mile radius of the crater, is possible at any time, scientists have said.

ASHFALL ADVISORY HAS BEEN ISSUED FOR NEARBY CITIES.

[george_r_1961]

Im not a volcano expert but I think another major eruption is near.

[HURAKAN]

Im not a volcano expert but I think another major eruption is near.

Is possible, but of all the active volcanoes in the US mainland the one that concerns me the most is Mt. Rainier, which hasn't erupted in centuries, and it's covered complete by snow and glaciers. Also, its base is very populated and even a small eruption could cause a part of the glaciers to melt and a mudslide of catastrophic porportions can occur.

[michaelwmoss]

Makes you wonder: Why ANYONE would live next to a mountain that has a history of Violent eruptions in the past. I know it's pretty there, but that makes no sense to me.

[gboudx]

Makes you wonder: Why ANYONE would live next to a mountain that has a history of Violent eruptions in the past. I know it's pretty there, but that makes no sense to me.

What's more interesting is why people choose to live so close to Mt Vesurvius. This volcano destroyed an entire city(Pompeii) and has killed thousands more over the past 1000 years with eruptions.

[michaelwmoss]

About how many people live there today>?

[gboudx]

About how many people live there today>?

Vesuvius? Here's some info:
http://www.italiaplease.com/eng/megazin ... 5/vesuvio/
Vesuvius is right in the middle of one of the most intense areas of volcanic activity on the Earth. Add a high density of population, some two million people live in and around the volcano, and you can get some idea of the danger involved.

[michaelwmoss]

GOOD NIGHT! I would be finding a way to move all of them NOW !

[Aslkahuna]

One of the current cities around Vesuvius is actually built on top of the ruins of Herculaneum-a town buried by ashfall, pyroclastic flows and lahars from the same AD 79 eruption that did the number on Pompeii. Problem is, it's not just Italy where this problem of big populations around volcanoes exist. Two of the biggest eruption death tolls in the last Century occurred with relatively modest eruptions-in St Pierre Martinique in 1902 where 30000 dies in two minutes from a Pyroclastic Flow and in Armero, Colombia where 22000 died in a few minutes from a Lahar from Nevado del Ruiz in 1985 (incidentally, the Armero scenario is one that worries volcanologists about Rainier)-the latter event led to the formation of the USGS VCAT-which had great success in the Philippines with Pinatubo.

Steve

[Cookiely]

Makes you wonder: Why ANYONE would live next to a mountain that has a history of Violent eruptions in the past. I know it's pretty there, but that makes no sense to me.

Why do people live in Galveston? Why do people live in Key West? I suppose its because its home. Rivers flood and homes are buried and people rebuild in the same spot decade after decade. Why do people live in the barrier islands of North Carolina or earthquake prone California? Same thing.

[TT-SEA]

Actually... very few people live in the immediate vicinity of Mt. Rainier. The area around there is a National Park.

And it is BEAUTIFUL.

If it were to blow... it would cause the total destruction of the National Park but Seattle would likely be untouched. Also... the ash plume would head east with the prevailing winds and away from Seattle just like when Mt. St. Helens blew in 1980.

Yes... we all choose to live with some type of danger.

[snow_wizzard]

TT is pretty much right on when he says that not too many people live where Mt. Rainier would totally wipe them out, but there are many who live where they would still be in danger. The rivers that run off of the mountain's melting glaciers run through Seattle, Tacoma, and other major cities. The torrents of water that could rush down these rivers in a major eruption is beyond comprehension.

For anyone that has not seen Mt. Rainier...It is AMAZING. It's shear massiveness and amount of glaciation is beyond what words can describe, and pictures do not do it justice. The peak has been deemed one of the most dangerous mountains on Earth.

[Aslkahuna]

Paleogeological studies show that major Lahars from Rainier have indeed made it to the Puget Sound along those rivers and pose a major risk to the people living along those rivers. The Pinatubo eruption as violent as it was killed about 300 people-a low death toll thanks to the evacuations before the eruption and it was largely due to collapsing roofs from the weight of wet ashfall with the ash mixing in with the rains from Typhoon Yunya. The lahars from Pinatubo have killed many, many more and displaced many more than those evacuated before the eruption and those lahars are still continuing 14 years after the eruption.

Steve

[Aslkahuna]

BTW, it should be pointed out that the town of Armero which was totally wiped out by the lahar from Nevado del Ruiz was located about 20-30 miles from the volcano. The Lahar from Mt. St. Helens down the Toutle River made it down to the Columbia River with enough debris in it to force clossure ot the Port in Portland OR. Fortunately, Shasta has a big dam below it across the Sacramento River that could possibly slow things down were it to blow and Lassen Peak, which last erupted in 1922, is not near anything.



Steve

[P.K.]

Talking of volcanoes have they shown Super Volcano over there yet? I think I read somewher it is being shown there in April but I may be wrong. If it is on then I'd advise watching it (Unless you live over Yellowstone of course )

Information from the BBC about this : http://www.bbc.co.uk/sn/tvradio/programmes/supervolcano/index.shtml - Although that picture shows a car out driving a pyroclastic flow which is highly unlikely.

[vbhoutex]

Talking of volcanoes have they shown Super Volcano over there yet? I think I read somewher it is being shown there in April but I may be wrong. If it is on then I'd advise watching it (Unless you live over Yellowstone of course )

Information from the BBC about this : http://www.bbc.co.uk/sn/tvradio/programmes/supervolcano/index.shtml - Although that picture shows a car out driving a pyroclastic flow which is highly unlikely.

That is all but impossible, but we must remember we are only watching a tv show, not real life.

Is it presented as a documentary?

[P.K.]

Pyroclastic flows travel at up to 700kph don't they? It is a bit like when they drive on lava in Dante's Peak.

It is presented as a factual drama, and from what I have seen the facts within it are good. The lecturer in one of my geology modules certainly said it was good (I'm not sure how it relates to met either ) - They also showed a documentary afterwards which was very interesting.

[P.K.]

Here you go http://dsc.discovery.com/convergence/supervolcano/supervolcano.html