Nov. 12, 2004
By Eric Apalategui
The Daily News, Longview, WA

Mount St. Helens' new lava dome is starting to push its increasing weight around, even beginning to shift its older and larger cousin a few centimeters a day across the inside of the crater.

The current eruption is adding lava to the inside of the crater faster than previous dome-building periods lasting at least a few weeks that occurred between 1980 and 1986. Geologists currently consider the new growth a separate dome but later might describe it as a lobe to the older dome, depending on the growth pattern, Willie Scott, a geologist with the U.S. Geological Survey's Cascades Volcano Observatory in Vancouver, said Thursday .

The new dome is now taller than the original bulge but still about a quarter to a third of its size. Earlier size estimates for the new dome included the glacial ice cap above it, but much of that has melted off. The dome is still growing by several meters each day, Scott said.

"Here we have a moderate rate (of dome growth) that's been going on for a month," since lava reached the floor of the crater Oct. 11, Scott said. "In that sense it's certainly different from what we saw in the past."

Scientists figure that, if the dome somehow sustains its current growth rate, Mount St. Helens would replace all the rock blasted away in 1980 within 11 1/2 years.

"That is the process by which the volcano will rebuild itself," Scott said. How long that takes, he added, "We just don't know."

For example, the old summit of Mount St. Helens took at least 100 years to form in the 15th and 16th centuries, scientists say.

Steam continues to drift out of the crater, sometimes accompanied by small plumes of ash that fall on the volcano's flanks.

Due to calming earthquake activity and relatively low gas emissions, scientists still don't anticipate any explosive eruptions large enough to threaten people in a wider area around the mountain, as occurred in May 1980.

"Conditions could change quite quickly, is the reason we're watching it closely," Scott cautioned.

The rising lava continues to melt part of the crater's glacier, which wraps around the old dome. However, the melt-off isn't occurring fast enough to pose a flood risk, Scott said. The melting ice becomes steam, seeps into the ground or trickles off the slope in small amounts.

In the future, hot landslides could further erode what had been one of the world's few expanding glaciers, he added.

"It's an interesting conflict between fire and ice --- who's going to win?"

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