Posted on 10/01/2004 11:27:26 AM PDT by Dog Gone
There is a 70 percent chance that Mount St. Helens will erupt by the end of October, with an explosion that could blast fist-sized rocks as far as three miles, geologists said Thursday.
The eruption would be relatively small, with steam or molten rock limited to the crater, said U.S. Geological Survey research scientist Tom Pierson. Ash might travel as far as 50 miles from the mountain, he said.
Thursday the Department of Natural Resources restricted access within a 12-mile radius around the mountain, joining Weyerhaeuser, which closed its St. Helens Tree Farm to the public earlier in the week.
With increasing earthquake activity riveting national attention on the volcano, U.S. Secretary of the Interior Gayle Norton announced Thursday that she will visit the Cascade Volcano Observatory in Vancouver, Wash., over the weekend. The observatory houses the USGS team tracking the mountain.
Meanwhile, local officials are double checking emergency plans and trying to get ready for whatever the mountain throws their way.
"We're not anticipating any problems, and we don't want to cause public alarm, because we have no reason to do that," Capt. Don Barnd of the Longview police said Thursday. "Our business is to prepare for 'what if,' and that's what we're trying to do."
Recalling the ash dumped all over Cowlitz County in the aftermath of "the big one," the department has purchased dust masks and filters to protect patrol car engines as a precaution, Barnd said. Geologists do not expect any major ash fallout.
Police have also prepared plans for emergency 12-hour shifts should they be needed to respond to an eruption, major flood or other unexpected event, he said.
Police precautions go far beyond what the USGS expects is necessary.
As new data has come in, scientists have refined their theories about the cause of the quakes. Temblors have been registering three or four per minute and spiked to a new high --- magnitude of 3.3 --- on the Richter Scale Thursday morning.
Scientists now believe that a small amount of molten rock that moved up into the volcano during a swarm of earthquakes in 1998 is edging its way toward the lava dome from a depth of about 1.25 miles.
A wet summer may be partly to blame.
According to current USGS hypothesis, ground water flowed toward the conduits --- or pipes --- that carry molten rock (magma) up from under the volcano. As it neared the conduits, the water became hot and changed to steam, expanding and causing fractures in the rock.
These fractures may have caused the initial earthquakes, which in turn triggered the magma to move up until it encountered hardened lava that had plugged the conduits. The combination of steam, earthquakes, and force of rising magma may be clearing away that natural plug, according to Pierson.
When the plug gives way, steam or magma now under pressure could explode, Pierson explained.
The good news, said USGS geologist Cynthia Gardner, is that the magma working its way up does not appear to be highly explosive because most of its gas has been vented off over several years.
Three USGS flights above Mount St. Helens this week have found only low levels of volcanic gasses.
USGS predictions are based on observations of Mount St. Helens and other volcanoes. The agency accurately predicted most of the eruptions at Mount St. Helens between 1981 and 1986, when the mountain last erupted.
The mountain's eruption on May 18, 1980, killed 57 people, sent a cloud of ash around the earth and flatted 230 square miles of forest.
Q & A
Experts answer questions about possible risks, staying prepared
Portland TV stations are projecting the trajectory of any ash plumes that might burp out of Mount St. Helens.
Wednesday night, a report on Mount St. Helens on the ABC evening news showed hot lava pouring out of an Hawaiian volcano.
All this might suggest that Southwest Washington's famous volcano is about to bury the region under ash and molten rock.
That's not the case, experts assure. For now, at least, geologists envision nothing more serious than the eruption on March 19, 1982, which shot a plume of ash to about 30,000 feet and sent a mudflow about 17 miles down the north fork of the Toutle River.
With all the media hubbub about the impending eruption, The Daily News went to the experts to find out what the risks are and how the public should prepare.
What is the worst case scenario?
"Our worst case is a small to moderate eruption, sending ash maybe as far as 30,000 feet into the air, and chunks of rock big enough to hurt people flying as far as maybe three miles," U.S. Geological Survey research scientist Tom Pierson said Thursday.
What should I do if there is an emergency?
Police and fire departments will sound a special high-low siren in the event of an emergency. "It means you should go turn on your AM radio or your TV and listen for news," said Cowlitz County Sheriff Bill Mahoney.
The state Enhanced 911 Office says you should stay off the phone unless you have a critical need. Do not call 911 unless you need medical, fire or police assistance.
Even in the worst case scenario, property and lives should not be at risk as long as people obey U.S. Forest Service restrictions, according to federal alerts issued this week.
Where can I get a safe look at Mount St. Helens?
Johnston Ridge Observatory is open, but hiking trails in the immediate vicinity of the mountain are closed. Climbing the volcano is barred.
Online, watch the mountain on the Volcano Cam at http://www.fs.fed.us/gpnf/
A new glacier has formed inside Mount St. Helens' crater since the volcano's last period of activity. Could an eruption cause this glacier to melt and flood the Toutle Valley?
"If there was an explosive eruption and hot material interacted with the glacier, there could be some melting, but it is extremely unlikely that the entire thing would melt," Pierson said.
An eruption starting under the ice would cause the most melting, with a flood comparable to the one triggered by the explosive eruption on March 19, 1982, Pierson said. On that date, a mud flow traveled about 17 miles, stopping near the old Camp Baker. The mud flow did not reach the lower Toutle or Cowlitz rivers.
Can the U.S. Army Corps of Engineers' sediment retention dam on north fork of the Toutle River hold back eruption debris?
Jim Griffith, a member of the Corps team that designed the dam, said the structure would help remove some of the mud, rock and other debris that could come downstream with a modest eruption. The dam also would reduce downstream damage from a larger mud flow, but it would pass some debris through its spillway.
"Unless have an unusually large eruption, I don't think the downstream communities are in any great danger," Griffith said.
Scientists with USGS said the eruption will not be big enough to cause problems.
Read more at http://www.nwp.usace.army.mil/op/srs/srs.asp
Will the volcanic activity trigger an earthquake along the Mount St. Helens seismic zone, a shallow fault extending northwestward fro the volcano?
"Right now the earthquakes are small and shallow, so we aren't looking at stresses large enough to trigger other earthquakes," said USGS seismologist Seth Moran.
The earthquakes at Mount St. Helens are about a half mile deep. A quake 10 or more miles deep would be more likely to trigger earthquakes in Mount St. Helens seismic zone, Moran said.
How much ash is likely to come out of the mountain?
An eruption could cause ash plumes anywhere from 100 feet to 30,000 feet high, said USGS geologist Cynthia Gardner.
People living within 50 miles would be the most affected by ash, though where ash falls would depend on prevailing winds, said scientist Pierson. Geologists are not expecting significant accumulations of ash beyond the immediate vicinity of the volcano.
If volcanic ash does drifts out to communities surrounding Mount St. Helens, what should people do?
Wear masks or wet cloths in front of noses and mouths to protect lungs. Keep ash out of buildings, machinery, vehicles and storm drains as much as possible. Ash can damage a car's engine, so don't drive while ash is falling. If you do have to drive, change your oil, oil filter and air filter often to protect your engine.
Read more at http://volcanoes.usgs.gov/ash/todo.html
Where can people look for the latest information?
The USGS is posting its latest findings online at http://vulcan.wr.usgs.gov/Volcanoes/Cascades/CurrentActivity/current_updates.html
meh....outside of the geology world this is a non-event.....overhyped.
"fist sized rocks thrown 3 miles"....doubt this even impresses your typical 15yr old palestinian.
After living with the stress of 4 Hurricanes here in Tampa Bay I want to send best wishes to all in the northwest. Hopefully it will be just a small burp and not a huge blast.
Best of luck northwest freepers.
Wear masks or wet cloths in front of noses and mouths to protect lungs. Keep ash out of buildings, machinery, vehicles and storm drains as much as possible. Ash can damage a car's engine, so don't drive while ash is falling. If you do have to drive, change your oil, oil filter and air filter often to protect your engine.
...collect ash in bottles and sell it to tourists.
Let's be real and say 99% and give the people sensible warning. People died the last time and their deaths were unnecessary.
Interestingly I seem to see the same mythology being built around the 1980 eruption as has been built around Hurricane Andrew..that "they" didn't forecast the storm (NHC, USGS, I guess) or predict the eruption.
The USGS had just finished a report two years prior to the 1980 eruption warning of the destructive potential of Mt. St. Helens. They were constantly arguing in favor of larger exlcusion areas and road closures around Mt. St. Helens. They were repeatedly warning of the dange of a large avalanche from the bulge.
The people that were disbelieving were local authorities, loggers, and residents.
I was road racing in Portland Oregon (GI Joes Trans-AM) in 1980 when the last eruption ocurred. I collected a can of ash off of my race car trailer that I still have to this day.
If I had to listen to Airhead Ketchupman's spiel, I'd erupt in plain downright boredom, not to mention that I'm sharing the west side of the state with the likes of Patty "Moron" Murray, Maria Cant"budget"well, Baghdad Jim McDermott and Gary Locke, the first Chinese-American governor as he and press like to bill him.
Per ABCNEWS - It just blew
I guess they ought to raise those odds a tad, then.
What did you know and when did you know it? Posted 30 minutes before the erruption (minor though it was)? We in the CIA don't believe in coincidences.
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