Posted on 09/29/2004 10:29:55 AM PDT by Michael Goldsberry
MOUNT ST. HELENS, Wash. -- The lava dome in Mount St. Helens' crater apparently is growing, possibly a new sign of an impending eruption, but a major explosion doesn't seem likely, a top volcano scientist said today.
"There seems to be some movement in the lava dome," said Jeff Wynn, chief scientist at the U.S. Geological Survey's Cascade Volcano Observatory in Vancouver, Wash., about 50 miles south of the mountain.
The pressure could come either from a buildup of gases within the 8,364-foot volcano, which erupted with devastating force in 1980, or from molten rock moving into the dome, Wynn said. The volcano began stirring again last week.
Seth Moran, a seismologist at the observatory, estimated the initial movement at 4 centimeters, about an inch and a half.
Wynn said the movement "sort of suggests that we're getting closer" to an eruption that could hurl rocks and ash a few thousand feet into the air.
(Excerpt) Read more at chron.com ...
I wouldn't want to be the guy flying the plane that drops the bomb. :)
Earthquake triggers landslide which pops the cork on the bottle and it all goes up.
"...a top volcano scientist."
Weren't they some of the first killed when the previous MSH eruption occurred?
One of those new generation of GPS-guided bunker busters from altitude.
Don't know if anybody mentioned it, but they raised the threat level from 2 out of four to 3 today...
There's a webcam to watch at:
http://www.fs.fed.us/gpnf/volcanocams/msh/
but as of my writing, it's pretty socked in with fog,so not much to see...
Where did you read about the threat level?
The updates are on the PNSN page - I'll get the link for it in just a minute here.
I'm glad the MSM is starting to cover this - finally.
True, had Bush converted to communism and radical Islam like the Democrats wanted him to, this all could have been avoided... ;-)
I saw that NBC Nightly News did a story on Mount St. Helens last night.
Cascade Range Current Update |
U.S. Geological Survey, Vancouver, Washington University of Washington, Pacific Northwest Seismograph Network, Seattle, Washington Mount St. Helens Volcano Advisory (Alert Level Two) Over night, seismic activity at Mount St. Helens has accelerated significantly, which increases our level of concern that current unrest could culminate in an eruption. We are increasing the alert level to the second of three levels, which is similar to Color Code Orange of the alert system used by the Alaska Volcano Observatory and analogous totheNational Weather Services hazardwatch. Earthquakes are occurring at about four per minute. The largest events are approaching Magnitude 2.5 and they are becoming more frequent. All are still at shallow levels in and below the lava dome that grew in the crater between 1980 and 1986. This suggests that the ongoing intense earthquake activity has weakened the dome, increasing the likelihood ofexplosions or perhaps the extrusion of lava from the dome. The cause and outcome of the accelerating unrest is uncertain. Explosions from the lava dome could occur suddenly and without further warning. During such explosions the dome and crater floor are at greatest risk from ballistic projectiles, but the rim of the crater and flanks of the volcano could also be at risk. Explosions would also be expected to produce ash clouds that rise several thousand feet above the crater rim and drift downwind. During today, wind forecasts from the National Weather Service, combined with eruption models, show that ash clouds will move in a southeasterly direction and could dust areas tens of miles or more from the volcano with ash. Landslides and debris flows from the crater that are large enough to reach the Pumice Plain are also possible. If the current unrest is being driven by a small slug of magma at shallow depth, extrusion of lava could also occur. At present there is no evidence that new gas-rich magma has ascended to shallow levels and could generate a large sustained eruption. But we are being especially vigilant to become aware of such evidence should it appear. We continue to monitor the situation closely and will issue additional updates as warranted, whether activity escalates or returns to background levels. Daily updates of earthquake data and other information can be found on the WORLD WIDE WEB at URL: http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity and http://www.pnsn.org/HELENS/welcome.html |
Return to:
[Cascade Range Current Activity Menu] ...
[Cascade Range Volcanoes and Volcanics Menu] ...
Go to:
[Mount St. Helens Current Activity Menu] ...
Link to:
[USGS Volcano Hazards Program Updates Page (includes Alaska, Hawaii, and Long Valley)] ...
[University of Washington's Pacific Northwest Earthquake Information (current seismicity)]
U.S. Geological Survey, Vancouver, Washington
University of Washington, Pacific Northwest Seismograph Network, Seattle, Washington
Mount St. Helens Volcano Advisory (Alert Level Two)
September 29, 2004 10:40A.M., PDT
Over night, seismic activity at Mount St. Helens has accelerated significantly, which increases our level of concern that current unrest could culminate in an eruption. We are increasing the alert level to the second of three levels, which is similar to Color Code Orange of the alert system used by the Alaska Volcano Observatory and analogous totheNational Weather Services hazardwatch. Earthquakes are occurring at about four per minute. The largest events are approaching Magnitude 2.5 and they are becoming more frequent. All are still at shallow levels in and below the lava dome that grew in the crater between 1980 and 1986. This suggests that the ongoing intense earthquake activity has weakened the dome, increasing the likelihood ofexplosions or perhaps the extrusion of lava from the dome.
The cause and outcome of the accelerating unrest is uncertain. Explosions from the lava dome could occur suddenly and without further warning. During such explosions the dome and crater floor are at greatest risk from ballistic projectiles, but the rim of the crater and flanks of the volcano could also be at risk. Explosions would also be expected to produce ash clouds that rise several thousand feet above the crater rim and drift downwind. During today, wind forecasts from the National Weather Service, combined with eruption models, show that ash clouds will move in a southeasterly direction and could dust areas tens of miles or more from the volcano with ash. Landslides and debris flows from the crater that are large enough to reach the Pumice Plain are also possible. If the current unrest is being driven by a small slug of magma at shallow depth, extrusion of lava could also occur. At present there is no evidence that new gas-rich magma has ascended to shallow levels and could generate a large sustained eruption. But we are being especially vigilant to become aware of such evidence should it appear.
We continue to monitor the situation closely and will issue additional updates as warranted, whether activity escalates or returns to background levels.
Ping!
We are now in an "eruption watch" This is the only level left below "actual eruption" level.
No discovery of SO2 or CO2 ...yet.
USGS will have another news conference at 2 PDT.
King 5 says impacts could happen up to 5 km from the mountain.
I take back my prior criticisms of the USGS et al for being too slow to report actual danger. Now if they would be so forthcoming about Rainier I'd feel better. This change in alert level is good - better safe than sorry. (I'm really glad to hear the downwind report takes the ash cloud into the unpopulated areas of the Cascades instead of up here to my area.)
So it will erupt BEFORE it actually erupts.....
(rolling eyes)
I live about 60 miles north of Mt. St. Helens. Though we'd be uneffected by an eruption, all of Sough Pudget Sound's gas and electric runs right past it. Back in '80 we were without both for about a week.
I wonder how King 5's on site truck feels about that???? All of the TV rigs are sitting in direct line of sight with the dome, within that 5 km.
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