Posted on 09/07/2005 10:35:31 AM PDT by LesbianThespianGymnasticMidget
BEND, Ore. (AP) -- A recent survey of a bulge that covers about 100 square miles near the South Sister indicates the area is still growing, suggesting it could be another volcano in the making or a major shift of molten rock under the center of the Cascade Range.
Recent eruptions at nearby Mount St. Helens in Washington state have rekindled interest in the annual Sisters survey and its findings.
Oregon has four of the 18 most active volcanoes in the nation -- Mount Hood, Crater Lake, Newberry and South Sister. A recent U.S. Geological Survey report said monitoring is inadequate at all of them, with only basic monitoring at about half of the active volcanoes.
Image Galleries
The Fury of Volcanoes
Mount St. Helens in 2004
Unlike the volcanoes, the bulge gets an extensive annual survey to track its growth. Spread out across an area nearly as big as the city of Portland, It's centered about three miles southwest of the South Sister, about 25 miles from Bend.
The results of the late August survey won't be ready for weeks, but scientists have reached some conclusions about the bulge from past monitoring.
They say it probably began growing in 1997 and has been rising ever since at a rate of about 1.4 inches a year. It was first observed from space using a relatively new imaging technology known as radar interferometry that can measure changes in the Earth's surface.
The likely cause of the bulge is a pool of magma that, according to Deschutes National Forest geologist Larry Chitwood, is equal in size to a lake 1 mile across and 65 feet deep.
The magma lake is rising 10 feet each year, under tremendous pressure, and it deforms the Earth's surface as it expands, causing the bulge.
Other causes could be anything from the birth of a new volcano -- a fourth Sister in the making -- to a routine and anticlimactic pooling of liquid rock, researchers say.
"The honest and shortest answer is, we don't know,'' said Dan Dzurisin, a USGS geologist.
Dzurisin recently led a three-person leveling crew on a slow walk across the top of the bulge. They were hoping to detect any change in its surface using survey equipment accurate to one-sixteenth of an inch for every mile measured.
Dzurisin's survey data, in concert with space imaging and satellite positioning measurements from two dozen fixed points on the bulge, give scientists an idea of the bulge's depth and size.
Additional information from seismographs and chemical monitoring of area springs reveal movement of the magma underground. A swarm of 350 small earthquakes in March 2004 indicated magma was on the move, but the bulge has been quiet ever since.
Whether the magma will move again or ever reach the surface is a mystery. But if it did, geological history suggests it would result only in small cinder cones that spew ash and lava.
The good news is that such an eruption likely would not seriously affect any population centers, Chitwood said.
Such cones are the most common volcanic features on Earth, he added. Central Oregon has about 600. Basalt flows have occurred in the area of the bulge every 1,000 to 1,500 years for the past 4,000 years, he said. And the area is due for another.
"The bulge is on time,'' Chitwood said. "The bus has arrived.''
Actually the rate of rise will increase as the depth (and therefore the pressure holding it down) decreases. It may be sooner.
I don't know what people consider close or far, but the fact remains St. Helens is part of the same mountain range, fault line, plate, etc... Which happens to be one of the most active volcanic regions on the Earth.
According to today's update of St. Helens, it also has a growing dome again. I completely understand the attempts at humor, but I don't think geologists are quick to dismiss the possible connections between all of the "geological" activity happening up and down the left coast.
Thanks for the info. What brought it to mind was a PSA saw for a foundation that cares for Rescue dogs...If you come across anything re the use of dogs in NOLA, start a thread....BTW..not sure if you saw the htread about the mules running loose in NOLA..I'll ping you..regards
It's all Bush's fault! ;)
Crater Lake is atop Mount Mazama.
--Karl Rove is creating yet another disaster?---
Karl Rove the hoodoo man,
brings out the storms
with a wave of his hand,
brings up the mountains
with a stomp of his shoe
gonna bring them black copters
to get crazies like you!
Thanks for the graphic.
Anything showing the topography around Mount St. Helens?
Honest
Really, don't worry
Does I am dumber than dirt Senator Ron Wyden and the MSM have their emergency plan in place for a mega eruption???
That's a major gotcha... climbing the mountain, suddenly, bam, splash...
This could be a catastrophism ping for GGG, but I'll probably just add it to the catalog when I get home.
BTTT
See where this is happening, kiddo?
...forewarned *is* forearmed.
Please FREEPMAIL me if you want on or off the
"Gods, Graves, Glyphs" PING list or GGG weekly digest
-- Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
Gods, Graves, Glyphs (alpha order)
Hmmmmm.
However, Mt St Helens is not in Oregon.
Where?
Eastern Oregon? Cowgirls.
The valley woman look unisex, the woman in my community on the coast look round and short like me.
The only woman/girls that are attractive are the ones my son oogles at in the commununity around OSU/Corvallis and they are almost to young for his 26yr old self to be wrenching his neck around.
No, no, no. The bulge is his fault!!! :)
Of course, now all the female mountains ask, "Is that a new volcano or are you just happy to see me?"
I just got home from being gone all day and I the first thing I see is the 57 yr old gal who had food and water and she was TACKLED by Cali LE who are in New Orleans.
She told them through the window she was fine and they said they just wanted to see. She had her gun in her hand but was just holding down by her side not even in the fashion one would if they were going to use it.
I thought them tackling that petite senior gal who was just fine in her home was DISGUSTING!
I know one thing we use to go and soak in the hot springs spa water in that area and if was so theraputic for my sons Cerebral Palsy, totally turned him into a wet noodle giving him relief from severe spasticity.
He grew up and is to tall/big to pack around now but man those were some awesome trips.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.