[Geysers] 9/29 Alert raised WED eruption predicted at Mount St. Helens

[V]

>From the Billings Gazette 
posted by Vicky

September 29, 2004 - 3:18 pm
Small or moderate eruption predicted at Mount St. Helens
Associated Press

http://billingsgazette.com/index.php?id=1&display=rednews/2004/09/29/build/nation/35-st-helens.inc

SEATTLE, Wash. — Mount St. Helens began rumbling more 
intensely Wednesday, prompting scientists to warn that a 
small or moderate eruption could happen in the next 
few days.

Earthquakes ranging from magnitude 2 to 2.5 were coming 
about four times a minute, possibly weakening the lava dome 
in the crater of the 8,364-foot mountain, the U.S. Geological 
Survey said.

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. But a small or moderate blast could coat an 
area three miles around the volcano's crater with ash and rock, 
scientists said.

Few people live near the mountain, which is surrounded by a 
national forest. The closest structure is the Johnson Ridge 
Observatory, about five miles from the crater.

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 system.

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.

"An aircraft can move the hell out of the way fast," said Jeff Wynn, 
the chief scientist at the survey's Cascade Volcano Observatory. 
"We don't want anyone in there on foot."

The USGS has been monitoring St. Helens closely since last 
Thursday, 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 
forests and paralyzed towns and cities more than 250 miles 
to the east with volcanic ash.

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