Longview Daily, Eruption Continues
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Monday updates: St. Helens still producing lava
By Staff, Longview Daily News
Jan 23, 2006 - 06:21:26 am PST
As lava oozes into Mount St. Helens' crater, it's squeezing out past underground clogs in the volcano's pipes, causing earthquakes every few minutes.
With snow and fog obscuring the crater for more than a month and keeping researchers away, U.S. Geological Survey scientists can't see what's happening up there firsthand.
But they can watch it all unfold remotely, thanks to dozens of instruments installed on the volcano over the past year.
"Seismometers record small earthquakes once every two to five minutes," USGS geologist Dave Sherrod said Friday in an e-mail update. That's an indication that the lava is still coming out.
Meanwhile, two global positioning system receivers, which can track tiny movements in time and space, are tracking the expansion of the dome formed by erupting lava.
The GPS receivers are moving apart at about one centimeter per day and probably are being shouldered aside by the extruding lava, Sherrod said.
Tiltmeters --- so named because they measure changes in incline or tilt --- are tipping very slowly, giving more signs that the lava is still coming out and deforming the inside of St. Helens' crater. Based on all these measurements, scientists believe the eruption has continued pretty much unchanged while the volcano is shrouded in clouds and snow, Sherrod said. -- Courtney Sherwood/The Daily News
