Mount St. Helens likely to erupt

[WSUCougar]

I remember the big eruption quite well, and though not in its path I do recall seeing the damage as well as the tons of ash and its effects.

Thankfully, this one sounds nothing like that catastrophe.

SEATTLE, Washington (AP) -- The flurry of earthquakes at Mount St. Helens intensified further Thursday, and one scientist put the chance of a small eruption happening in the next few days at 70 percent.

Jeff Wynn, chief scientist at the U.S. Geologic Survey's Cascade Volcano Observatory in Vancouver, Washington, said tiny quakes were happening three or four times a minute. Larger quakes, with magnitudes of 3 to 3.3, were happening every three or four minutes, he said.

New measurements show the 975-foot lava dome in the volcano's crater has moved 2 1/2 inches to the north since Monday, Wynn said.

"Imagine taking a 1,000-foot-high pile of rocks and moving it 2 1/2 inches. For a geologist, that's a lot of energy," Wynn said.

Wynn estimated there was a 70 percent chance the activity will result in an eruption.

Scientists did not expect anything like the mountain's devastating eruption in 1980, which killed 57 people and coated towns 250 miles away with ash. On Wednesday, they warned that a small or moderate blast from the southwest Washington mountain could spew ash and rock as far as three miles from the 8,364-foot peak.

Scientists planned to fly over the volcano again Thursday to test for gasses that could indicate the presence of magma moving beneath the volcano.

Few people live near the mountain, which is in a national forest about 100 miles south of Seattle. The closest structure is the Johnston Ridge Observatory, about five miles from the crater.

The heightened alert has drawn a throng of sightseers to observation areas. Dawn Smith, co-owner of Eco Park Resort west of the mountain, told The News Tribune of Tacoma, "It's just been crazy the past couple of days."

A sign in front of her business reads, "Here we go again."

The Geological Survey raised the mountain's eruption advisory from Level 2 to Level 3 out of a possible 4 on Wednesday, prompting officials to begin notifying various state and federal agencies of a possible eruption. The USGS also has asked the National Weather Service to be ready to track an ash plume with its radar.

In addition, scientists called off a plan to have two researchers study water rushing from the crater's north face for signs of magma. A plane was still able to fly over the crater Wednesday to collect gas samples. Negligible amounts of volcanic gas were found.

"An aircraft can move ... out of the way fast," Wynn said. "We don't want anyone in there on foot."

The USGS has been monitoring St. Helens closely since September 23, when swarms of tiny earthquakes were first recorded. On Sunday, scientists issued a notice of volcanic unrest, closing the crater and upper flanks of the volcano to hikers and climbers.

Scientists said they believe the seismic activity is being caused by pressure from a reservoir of molten rock a little more than a mile below the crater. That magma apparently rose from a depth of about six miles in 1998, but never reached the surface, Wynn said.

The mountain's eruption on May 18, 1980, blasted away its top 1,300 feet, spawned mudflows that choked the Columbia River shipping channel, leveled hundreds of square miles of forest and paralyzed towns and cities more than 250 miles to the east with volcanic ash.

[sterlingice]

I've checked every few hours on their webcam:

hxxp://www.fs.fed.us/gpnf/volcanocams/msh/

SI

[WSUCougar]

SI = flat-lander living vicariously?

[sterlingice]

Originally Posted by WSUCougar

SI = flat-lander living vicariously?

Says the one located four hours to the east

Actually, I think the first paper I had to write for school was on Mt St Helens (basically based on the great National Geographic article about it). It was either that or the one on John Quincy Adams. Either way, once you write a paper like that, you check up on things once in a while and I noticed that in the news last week.

SI

[sovereignstar]

Originally Posted by sterlingice

I've checked every few hours on their webcam:

hxxp://www.fs.fed.us/gpnf/volcanocams/msh/

SI

Not to totally threadjack here and maybe I'm just extremely lazy, but why does the US Forest Service website need to be hxxp'd? What the hell is going on around here? Has everyone really lost all sight on what is and what isn't an appropriate link?

And spare me the "I'm just doing it to be safe" bullshit. This is not just directed to you, SI.

[Buzzbee]

Originally Posted by sovereignstar

Not to totally threadjack here and maybe I'm just extremely lazy, but why does the US Forest Service website need to be hxxp'd? What the hell is going on around here? Has everyone really lost all sight on what is and what isn't an appropriate link?

And spare me the "I'm just doing it to be safe" bullshit. This is not just directed to you, SI.

What does it matter? You too lazy to go TT?

[sovereignstar]

Originally Posted by Buzzbee

What does it matter? You too lazy to go TT?

When was it as simple as typing "TT" to get to one of these links?

[dawgfan]

Looks like the modest steam and ash plume from Thursday was just a precursor - a new eruption seems imminent:

Updated Seattle Times story on the Mt. St. Helens situation

To recap the update, there seems to be a significant movement of magma towards the surface, carrying with it volatitle gases. The magma pathway is plugged by the 1,000 foot tall lava dome in the center of the hollowed-out crater. The dome has been inching northward in the last week, and the steam/ash plume from Thursday was emmited from the south part of the dome through a glacier that has formed between the lava dome and the south end of the crater.

Moisture from that glacier has probably been seeping into the magma chamber, causing some of the trembling under the mountain, and the steam plume was undoubtably a reaction from that moisture reaching the super-hot magma.

While it's unlikely the new event will rival the original May 18th, 1980 eruption of the mountain, it could be one of the biggest since then. The potential explosiveness of the eruption will be governed by a few factors - the gaseous content generated/carried along with the magma, the age of the magma and the moisture content of the magma. While scientists first though this might be movement of magma that had originally been uplifting from 6 years back, they now think there may be fresh magma mixed in. If so, this magma would be more likely to carry explosive potential once it reaches the surface.

The biggest danger would appear to be from an ash plume interfering with airplane engines; any eruption will cause a diversion of nearby flights, and may ground some flights out of Portland International Airport. There is also a possibility of some mud flows if that glacier in the crater melts, though it's not expected the danger is anywhere close to what happened in 1980.