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SAN FRANCISCO -- An unusually smooth and swiftly growing lava dome within the crater of Washington state's Mount St. Helens volcano is an extraordinary and perplexing event with an unknown outcome, geologists said Tuesday.

The dome has been building at a steady clip for about two months now as molten rock boils up from deep below. While no major eruptions are expected in the near term, the dome's construction can be likened to a runaway freight train in terms of the steady forces involved, scientists said.

"There's a truckload of hot rock coming out of the mountain every second," said Dan Dzurisin of the U.S. Geological Survey. "We're scratching our heads about it."

Dzurisin and others presented the latest data on the volcano here at a meeting of the American Geophysical Union this week.

Waking up

When Mount St. Helens blew its top in 1980, it left a mile-wide crater. Over the next six years, a dome of lava built up in the middle of the crater. Then the volcano went quiet. The dome became partly buried by a glacier that's more than 600 feet deep in places.

Read more: http://www.livescience.com/forcesofnatu ... pdate.html

We are seeing the growth of new land! Hawaii was built in this manner. Maybe Mt. St. Helens is trying to re-add those missing 3000 feet?

Portland Natives still discuss the 1980 eruption. Apparently the ash was so thick that it shut everything down. If she erupts again, it looks like face masks will be THE spring fashion. Fascinating stuff.

A Karenina wrote: Portland Natives still discuss the 1980 eruption.


I remember it. It was extraordinary. The ash was 5" deep in places. Over 500 million tons of it.

Bill Sikes wrote: I remember it. It was extraordinary. The ash was 5" deep in places. Over 500 million tons of it.
Bill, you were here during that time? Gorgeous country, isn't it?



Just the other day a friend was saying that the only relief from the ash was when it rained, and for some reason he doesn't remember a lot of rain that year. The other big thing I pick up on is that the ash got into car engines - most of us don't have garages.

Explosive Predictions For Mount St Helens

By Philip Cohen

NewScientist.com



The recent "extraordinary" behaviour of one of the world's most notorious volcanoes, Mount St Helens in the US, may mean it is preparing for a dramatic eruption, geologists warned on Tuesday.



In late September 2004, a series of earthquakes signalled that the volcano was awakening. Since then, enough lava has oozed into the volcano's crater to build a dome the size of an aircraft carrier. The new dome, standing 275 metres off the crater floor at its highest point, is now taller than a nearby dome built by a previous set of eruptions over the course of six years.



"Something extraordinary is happening at Mount St Helens. We are scratching our heads about it," says Dan Dzurisin of US Geological Survey's Cascades Volcano Observatory (CVO) in Vancouver, Washington, US. The new dome has grown so quickly - almost four cubic metres every second - that it has bulldozed a 180-metres-thick glacier out of its way.



If this rapid growth rate continues, there is a growing risk of a dome collapse which could trigger a major eruption, researchers warned at the American Geophysical Union meeting in San Francisco.



But experts say that the pace could also soon slow down and the dome remain stable. To work out which scenario is more likely, geologists have been studying the process driving the lava flow and other factors that determine dome stability, such as the lava's physical properties.



Contingency plans Mount St Helens has been a hot bed of volcanic research ever since its deadly 1980 eruption - when part of its summit detached - spewed rocks and ash for hundreds of miles and created the largest landslide ever recorded in the US. Fifty-seven people were killed and thousands of animals in nearby forests were buried alive or choked by ash and debris.



Luckily today, if there were to be a major eruption, the immediate area is uninhabited and the US Army corps of engineers has built a dam in the nearby valley intended to protect against possible landslides.



More: http://www.newscientist.com/article.ns?id=dn6806