Seismic monitoring stations wanted
at Crater Lake
Herald and News
Klamath Falls, Oregon
September 17, 2005
By LEE JUILLERAT
No, Crater Lake isn't expected to have renewed volcanic activity
any time soon.
H&N photo by
Lee Juillerat Although officials have no evidence that
Crater Lake is ready to erupt, six to ten seismic
monitoring stations at and near Crater Lake Park have
But, yes, geologists with the U.S. Geologic Survey and Crater
Lake National Park officials would like to install six to 10
seismic monitoring stations at and near the park.
"The threat isn't that great," said Willie Scott, a geologist
with the U.S. Cascades Volcano Observatory in Vancouver, Wash.,
of a possible eruption. "Still, the level of monitoring is
minimal and needs to be improved."
A recent USGS report on a proposed National Volcano Early
Warning System said Crater Lake receives the least monitoring
for possible eruptions among the region's five most active
volcanoes, partly because it lies so far from population
''Crater Lake is the worst-case scenario,'' said observatory
seismologist Seth Moran. ''Mount Saint Helens taught us that we
need a decent network of seismic monitors or else we might miss
the subtle signs (of volcanism). Once they wake up, they're too
hot to get close to.''
There is a network of seismic monitors up and down the Cascades,
but the monitor nearest to Crater Lake is 29 miles away.
''In every (other) case, volcanoes have a monitor within five
miles, but Crater Lake is a remote volcano, not near any town,
and it hasn't erupted very recently,'' Moran said. ''To be
frank, resources are limited, so we have to concentrate on the
most likely ones: Rainier, Hood and South Sister.''
Geologists say the five Oregon volcanoes most likely to become
active are Hood, Jefferson, South Sister, Newberry and Crater
Lake. In far northern California, volcanoes of concern include
Shasta, Lassen and Medicine Lake.
"We're proposing a long-term strategy to improve volcanic
monitoring in the U.S.," Scott said. "A lot of volcanic swarms
and earthquakes are very small, and being able to locate them
precisely is very important."
Scott said implementing the desired network would cost about $15
million annually, which includes installation, extra personnel
Crater Lake's cataclysmic eruption happened about 7,700 years
ago. Wizard Island, the volcanic cone within the caldera,
erupted about 5,000 years ago. The eruption of the former Mount
Mazama was among the most spectacular volcanic events and left a
huge caldera that filled with rain and snow melt.
Since then, the only recorded signs of volcanic activity have
included gaseous clouds that emerged through the summer of 1945
and earthquakes that measured up to 6.0 magnitude in 1993.
"We have no indications that Crater Lake is poised to erupt,"
said Mac Brock, the park's chief of natural resources, who said
the report has caused some people to wonder if an eruption is
The park had a monitor several years ago but Brock said it was
removed. He said park officials have discussed the desire for
seismic monitoring systems "because it's always been something
we'd like to do," but no proposals have been made.
Scott said the proposed monitoring station would include a
station the size of a big steel toolbox on the ground or
partially buried, a thermometer-sized sensor, a mast and
antenna, and solar-powered battery panel.
"Restless volcanoes do not always progress to eruption," the
USGS reports says. "Nevertheless, monitoring is necessary in
such cases to minimize either over-reacting, which costs money,
or under-reacting, which may cost lives."
The Associated Press contributed to this story.
On the Web: volcanoes.usgs.gov