Quantcast
Last updated on April 25, 2014 at 1:22 EDT

CORRECTED-Scientists find growing land bulge in Oregon

September 12, 2005

In September 9 story headlined “Scientists find growing
land bulge in Oregon,” please read in first paragraph, “A
large, slow-growing volcanic bulge in Western Oregon,” instead
of “A large, slow-growing volcanic bulge in Eastern Oregon.”

A corrected story follows:

By Teresa Carson

PORTLAND, Oregon (Reuters) – A large, slow-growing volcanic
bulge in Western Oregon is attracting the attention of
seismologists who say that the rising ground could be the
beginnings of a volcano or simply magma shifting underground.

Scientists said that the 100 square-mile (260 sq-km) bulge,
first discovered by satellite, poses no immediate threat to
nearby residents.

“It is perfectly safe for anyone over there,” said Michael
Lisowski, geophysicist at the United States Geological Survey’s
Cascades Volcano Observatory in Vancouver, Washington.

The bulge is rising at a rate of about 1.4 inches per year,
according to a report issued by the U.S. Geological Survey.

The bulge is located in a sparsely populated area 3 miles

southwest of South Sister, a mountain 25 miles west of
Bend, Oregon.

Lisowski said the unnamed bulge was created because of a
big cavity, estimated to be about 4.5 miles below the surface,
that is filling with fluid.

The fluid is likely magma, but could also be water. It was
described in the report as a lake 1 mile across and 65 feet
deep.

The bulge is a bare patch of land with no residents, and
anyone in the area would not be able to see, feel or smell
anything, seismologists said.

South Sister is one of three volcanic peaks called The
Three Sisters, which are part of the Cascade mountain range.
The range includes four of the 18 most active volcanoes in the
United States, according to the U.S. Geological Survey.

The South Sister probably erupted last time about 2,000
years ago, seismologists said.

Further north, the 1980 eruption of Mount St. Helens killed
57 people, destroyed at least 230 square miles of forest and
spewed ash for hundreds of miles.

Mount St. Helens has rumbled back to life recently,
spitting lava, rocks and ash, but has not had another big
eruption.

A lava dome is growing in the huge crater created in Mount
St. Helens, but that event appears to be unrelated to the South
Sister bulge, seismologists said.

“Growth of the new lava dome inside the crater of Mount St.
Helens continues, accompanied by low rates of seismicity, low
emissions of steam and volcanic gases, and minor production of
ash,” the U.S. Geological Survey said in a daily report.

Scientists said they would continue to monitor the bulge,
most likely over a number of years.

“We haven’t seen anything like this in the Cascade range,”
Lisowski says, “although we have only been looking in the last
20 years.”