Longview News, Continuing Eruption
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Monday updates:
By Staff, Longview Daily News
As lava oozes into
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
