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15-month eruption still producing lava at astonishing rate (Mount St. Helens )
Seattle PI ^ | 12-29-2005 | PEGGY ANDERSEN

Posted on 12/30/2005 2:03:57 PM PST by Cagey

SEATTLE -- For more than a year now, Mount St. Helens has been oozing lava into its crater at the rate of roughly a large dump truck load - 10 cubic yards - every three seconds.

With the sticky molten rock comes a steady drumfire of small earthquakes.

The movement of lava up through the southwest Washington volcano is "like a sticky piston trying to rise in a rusty cylinder," U.S. Geological Survey geologist Dave Sherrod said Thursday in a telephone interview from the agency's Cascades Volcano Observatory in Vancouver, Wash.

"These quakes are very small - we think they're associated with that sticking and slipping as the ground is deformed and relaxes."

The mountain is about 50 miles north of Vancouver and 100 miles south of Seattle.

St. Helens' violent May 18, 1980, eruption blasted 3.7 billion cubic yards of ash and debris off the top of the mountain. A torrent of scalding mud poured down the north fork of the Toutle River. Fifty-seven people died in the blast, which left a gaping crater in place of the perfect, snowclad cone that had marked the original 9,677-foot peak known as "America's Mount Fuji."

St. Helens - now 8,325 feet - rumbled for another six years, extruding 97 million cubic yards of lava onto the crater floor in a series of 22 eruptions that built a 876-foot dome. The volcano fell silent in 1986.

Then in September 2004, the drumfire of low-level quakes began - occasionally spiking above magnitude 3, but generally ranging between magnitude 1 and 2. In the past 15 months, the mountain has squeezed out about 102 million cubic yards of lava.

Winter weather has prevented aerial monitoring of the crater since Oct. 24, "but we know what the rate has been. It's been relentless," Sherrod said, noting geologists can also rely on a network of remote monitoring equipment to tell them what's happening.

"One view of this eruption is that we're at the end of the eruption that began in 1980," he added. "If it hadn't been so cataclysmic ... it might instead have gone through 30 or 40 years of domebuilding and small explosions."

All the recent activity has remained within the crater, though scientists - keenly aware of the potential damage that silica-laced ash can pose to jet engines - monitor St. Helens closely for plumes of smoke and ash that can go as high as 30,000 feet.

"We haven't had that kind of plume since March 8, which is either a blessing or it leads us into complacency," Sherrod said, adding quickly, "We avoid complacency."

"This dome collapses and grows and collapses and grows. It changes its location ... it can't seem to maintain its height at much more than it is now " - about 1,300 feet. "Then it kind of shoves the sandpile aside and starts over."

It's not entirely clear where the lava is coming from. If it were being generated by the mountain, scientists would expect to see changes in the mountain's shape, its sides compressing as lava is spewed out.

At the current rate of extrusion, "three or four months would have been enough time to exhaust what was standing in the conduit. ... The volume is greater than anything that could be standing in a narrow 3-mile pipe," Sherrod said.

That suggests resupply from greater depths, which normally would generate certain gases and deep earthquakes. Neither is being detected.

"That's one of the headscratchers, I guess," Sherrod said.

St. Helens' unremitting, monthslong pace is not common, he said. "It's not a characteristic feature of volcanism."

The mountain is the youngest and most restless of the Cascade volcanos. "Most of what we see today is 4,000 years old," Sherrod said. By comparison, Oregon's Mount Hood is 30,000 to 50,000 years old. Parts of Mount Rainier in Washington date back 200,000 years.


TOPICS: News/Current Events; US: Washington
KEYWORDS: bushsfault; mtsthelens; volcano
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U.S. Geological Survey regional site: http://vulcan.wr.usgs.gov/Volcanoes/Cascades/CurrentActivity/

Pacific Northwest Seismic Network: http://www.pnsn.org/HELENS/welcome.html

1 posted on 12/30/2005 2:03:58 PM PST by Cagey
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To: Cagey
The mountain is about 50 miles north of Vancouver and 100 miles south of Seattle.

I had no idea that Vancouver was so far South of Seattle :)
2 posted on 12/30/2005 2:05:00 PM PST by MikefromOhio (Proud "Heathen" (although I regularly attend church) South Park watcher. Live with it.)
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To: Cagey

All that lava is going to warm the planet too much.

When Hildebeast gets elected she will put a stop to all this nonsense.


3 posted on 12/30/2005 2:06:31 PM PST by GaltMeister (“All that is necessary for the triumph of evil is that good men do nothing.”)
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To: MikeinIraq
Vancouver, WA. Its just north (across the Columbia) from Portland, OR.
4 posted on 12/30/2005 2:06:53 PM PST by canalabamian (Durka durka...Muhammad FUBAR!)
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To: MikeinIraq

Amazing what Volcanoes can do to geography, isn't it?


5 posted on 12/30/2005 2:07:03 PM PST by Cagey (If you can't hear me, it's because I'm in parentheses)
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To: Cagey

pong for later


6 posted on 12/30/2005 2:07:26 PM PST by Chani (Life is fatal. The 100% statistic is compelling.)
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To: canalabamian

I know....

It was in the article, but I decided to ignore it selectively....bad joke


7 posted on 12/30/2005 2:07:28 PM PST by MikefromOhio (Proud "Heathen" (although I regularly attend church) South Park watcher. Live with it.)
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To: Cagey

LOL


8 posted on 12/30/2005 2:07:42 PM PST by MikefromOhio (Proud "Heathen" (although I regularly attend church) South Park watcher. Live with it.)
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To: Cagey

I have a beautiful cerving made from St. Helens volcanic ash, that I got when visiting in September. 8^)


9 posted on 12/30/2005 2:09:11 PM PST by airborne (If being a Christian was a crime, would there be enough evidence to convict you?)
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To: GaltMeister
We've already got two beasts here in Sen. Murray and Cantwell. We sure don't need Hildebeast joining them.
10 posted on 12/30/2005 2:11:20 PM PST by jazusamo (A Progressive is only a Socialist in a transparent disguise.)
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To: Cagey; ecurbh; Ramius
For more than a year now, Mount St. Helens has been oozing lava into its crater at the rate of roughly a large dump truck load - 10 cubic yards - every three seconds.

Even after being there many times... I just can't see change in the dome...

Sept - 03:

July -05:

Doesn't look a lot different to me. So I guess I just can't grasp the scale of this thing.

11 posted on 12/30/2005 2:24:38 PM PST by HairOfTheDog (Join the Hobbit Hole Troop Support - http://freeper.the-hobbit-hole.net/ 1,000 knives and counting!)
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To: jazusamo
We've already got two beasts here in Sen. Murray and Cantwell. We sure don't need Hildebeast joining them.

As a fellow Washingtonian, I'd pay 5 bucks to watch the three of them wrestle nude - in Portland cement.

12 posted on 12/30/2005 2:26:24 PM PST by llevrok (Drink your beer, damnit! There are people in Africa sober.)
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To: HairOfTheDog

I believe it pushes up a huge pile of ashes, then reaches a crescendo that rolls on down the mountainside, likely in small increments.


13 posted on 12/30/2005 2:28:19 PM PST by UCANSEE2
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To: UCANSEE2

It does push up and crumble again. What was visible in person (that doesn't show up in the pics) was a large 'tower' that was new last time since my earlier visit. This tower was evidently many stories tall and was destined to fall over. Again, it's hard to grasp the scale of it, even when you are looking at it.


14 posted on 12/30/2005 2:32:29 PM PST by HairOfTheDog (Join the Hobbit Hole Troop Support - http://freeper.the-hobbit-hole.net/ 1,000 knives and counting!)
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To: Cagey

It is amazing the topography of the land can change in less than three minutes.


15 posted on 12/30/2005 2:34:40 PM PST by ThisLittleLightofMine
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To: llevrok

I'd pay five bucks to go to the event but I'd wear a blindfold, they're hazardous to your vision dressed.


16 posted on 12/30/2005 2:34:44 PM PST by jazusamo (A Progressive is only a Socialist in a transparent disguise.)
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To: llevrok

I'd pay five dollars to be excused from such an event.


17 posted on 12/30/2005 2:35:35 PM PST by lesser_satan
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To: goodnesswins
fyi

and --- Happy New Year.

18 posted on 12/30/2005 2:43:35 PM PST by GretchenM (God made you. He will also take you out. Better to go on His terms, that is, through Jesus.)
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To: HairOfTheDog

The new dome is behind of and uphill of the old dome, looking at them from the angle of the pictures you posted.

Of your two pictures, you can see the new dome most clearly in the July 05 picture. It is the slightly lighter shape behind and above the old dome. The steam plume appears to be coming from the top of it.

The problem with seeing the new dome is one of contrast. Viewed from the angle of these pictures it's the same shade of black and grey as the slope behind it.


Here's a link to the USGS Mt. St. Helens website, with a picture explaining the various features inside the crater:
http://vulcan.wr.usgs.gov/Imgs/Jpg/MSH/MSH05/MSH05_crater_from_north_with_whaleback_views_annotated.jpg

This link takes you to the main Mt. Saint Helens web site:

http://vulcan.wr.usgs.gov/Volcanoes/MSH/Images/MSH/


19 posted on 12/30/2005 2:46:51 PM PST by jimtorr
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To: Cagey

I remember the horrible drought we had in the midwest from her exploding in '80. Regarding this past summers' drought and OK and TX I keep telling people Saint Helen needs to shut her piehole.


20 posted on 12/30/2005 2:48:15 PM PST by Mrs. Shawnlaw (Rock beats scissors, don't run with rocks. NRA)
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