Oregon Is Growing A Mystery Bulge

nedwolf writes "LiveScience is reporting that a 100 square mile bulge has been rising in Oregon. First observed from a satellite using a relatively new technology called 'radar interferometry', some believe this to be the formation of a new volcano. I think it's just happy to see me."

Comments

Baby Sister?

[ackthpt]

Looks quiet now.

To put things into perspective here's recent quakes throught the US, notice the activity in the state of California, to the south.

Back in the late 90's there were swarms of minor earthquakes around the Long Valley Caldera, the vicinity of California where Mammoth Lakes and Mammoth Mountain are located. Swarms of earth quakes, 4.0 (Richter) and lower, most lower than 2.0, were up to 600 per 24 hours for a period of about two weeks, and ground elevations were observed changing (similarly to those in Oregon) slightly, but as you can see all is quiet and nothing happened. Long Valley is the caldera of a very large, dormant volcano.

Here is a good example of a swarm of aftershocks.

This would be a shield volcano

[ReformedExCon]

A shield volcano is formed when a large pool of magma forms and pushes the land above it upwards. These types are not likely to erupt, though they will erupt violently if the magma is able to push through the surface (kind of like a giant geologic pimple). These volcanos are great for tourism because of the typically accompanying hot springs and year-round greenery.

I like Oregon a lot. I just wish it were easier to get to.

Re:This would be a shield volcano

[Anonymous Coward]

Volcano lesson for the day:
This is not a shield volcano.

A shield volcano is actually made by layers and layers of basaltic magma. Hawaii (the large, flat volcanos) are shield volcanos. Basaltic magma is very hot, iron rich, and flows easily. It tends to bubble and gurgle, not explode. There's a reason hawaiian eruptions don't produce ash clouds - no big explosion.

http://volcanoes.usgs.gov/Products/Pglossary/Shiel dVolcano.html

In Oregon, we have very few shield volcanos. Most of ours are composite volcanos (made from lava pusing up a dome, plus layers of flowing ash) and cinder cones (made from piles of ejected cinders). Our magmas are rhyolitic, meaning they contain little iron, it is at relatively cooler temperatures, and tend to explode violently (like Mount St. Helens or the famous Mount Mazama... now crater lake).

http://vulcan.wr.usgs.gov/Glossary/StratoVolcano/d escription_composite_volcano.html

Re:This would be a shield volcano

[enzo_romeo]

Actually, if I recall correctly from my Geology 202 class at UW with Stan "the Man" Chernikoff, a shield volcano is formed from molten basalt flowing out, not pushing up the land. Basalt is what makes up the ocean floor and has very low viscosity when molten and spreads out like hot butter on a pancake. Flow after flow of lava slowly builds up to form a high spot. Hawaii is a classic shield volcano and is roughly 100 miles in diameter with only the top of it showing above the ocean.

The continents, however, are composed mainly of Granite, which has a higher viscosity and tend to not flow out easily and make taller piles of lava to create the cone shaped volcanos. Its generaly thought that the cascade mountain range and volcanos were formed by hot spots burning up through the granite crust at the subduction zone and thats why you have the cone shaped volcanos there. What we might see there is another cone shaped volcano being formed, which should be interesting to track in terms of how long it actually takes to create one of these. There are shield volcanos in Washington and Oregon though, so we could see one of those, however I think those are mainly seen in the eastern parts of the states. I'm going of a class I had in 1988 so I could be mistaken on that.

Re:This would be a shield volcano

[IceAgeComing]

In Oregon, we have very few shield volcanos. Most of ours are composite volcanos (made from lava pusing up a dome, plus layers of flowing ash) and cinder cones (made from piles of ejected cinders). Our magmas are rhyolitic, meaning they contain little iron, it is at relatively cooler temperatures, and tend to explode violently

But eastern Oregon is full of basalt, and the Malhuer Basin is one giant, flat basalt flow. And if you've seen the lava fields around Bend, the boulders are dark red, very sharp, and contain occasional pockets of obsidian. This doesn't seem to fit with your statements.

Re:This would be a shield volcano

[the phantom]

1) Obsidian is generally related to rhyolitic flows. Where basalt is high in iron and magnesium (thus, mafic -- ma from magnesium, fic from ferous or feric), rhyolite is full of silicon. Andesite is sort of in between. Silicic lava is very viscous -- it tends not to flow as well, and get backed up in a volcano. Then, when enough pressure is present, is 'slodes. Obsidian is a very, very silicic rock. It cools from lava to solid rock very quickly, so does not from a crystaline structure, but it is chemically very similar to rhyolite or pumice. Thus, that does not refute the grandparent, but rather reinforces it.

2) There have been basalt flows. It is possible for composite volcanoes to have basalt flows. Think about what composite means -- a combination of two or more things. Composite volcanoes are not quite sheild volcanoes, and not quite cinder cones. Eruptions can be either highly mafic, or highly silicic. Thus, basalt flows are not out of place.

3) The sharp, dark red rock that you are seeing is probably andesite. There is a lot of andesite in the region. Andesite is a fairly silicic rock (though it does get the red color from more mafic minerals). It is another kind of rock that can be expected to come from a composite volcano.

So, while your observations don't exactly fit with the grandparent's comment, they are not inconsistant.

Re:Same fault line

[geomon]

both regions lie along the same fault line.

No. Both regions sit atop the seismically active area named "The Ring Of Fire", which is a poetic name given to a seismically active rim boundary indicated by plots of earthquake epicenter. The purple band you see on the map is the area is the subduction zone of the Pacific Plate.

This is not a fault zone. Fault zones arise in response to subduction.

Re:square?

[Anonymous Coward]

It says 100 square miles, not 100 miles square. There's a difference.

Re:Mr. President, Dr. Evil is on the line...

[Anonymous Coward]

I just wish I'd stop seeing your ID on every single story...

You know, there's two really easy ways to make that happen:
1) Add TMM to your foes, downmod your foes into oblivion, and read above -1.
  -or-
2) Leave. No one is forcing you to read this website.

Re:Mr. President, Dr. Evil is on the line...

[Pharmboy]

You know, you can always mark his as a FOE, adjust your viewing to make all FOE posting -10 points. All you see is a single line. Its in the FAQ, and it's pretty easy. Lots of other stuff you can do there, too.

Re:Mr. President, Dr. Evil is on the line...

[JabberWokky]

Add him as a foe (click on the little white sphere), go to your Preferences (link in the upper left corner), pick "Comments" and change your People Modifier setting to drop all posts by foes to -6. You'll never see his comments ever again.

--
Evan

Re:New measurement technique != new geology

[CFTM]

An article I read on this yesterday stated that this is indeed normal, happens about once every 4,000 years and it's about time for it to happen again; wish I had the link but I don't :-/ Anyhow, this is just normal geological stuff, atleast according to what I read yesterday.

Another bulge

[Hoi Polloi]

Unfortunetly I know the cause of the bulge around my waist. The end of summer cookouts should help.

Seriously though, if you have ever been to the Three Sisters Wilderness you quickly see that the whole area is one huge mass of old cones and lava flows. It is like hiking on the moon in some places.

Re:New measurement technique != new geology

[Scarblac]

They are now able to detect this swelling...how do we know it isn't normal.

We don't, of course. The bit below is from a mysterious item usually related to as "the fucking article", bolding mine:

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.

Re:Super Volcano?

[jim_v2000]

If this is indeed another one, then the fallout from Katrina is going to seem mild in comparison.

I live in Oregon, and let me tell you, if a volcano blew 25 miles from Bend, the most we'd lose is some trees and scrub brush. Even if Bend got taken out...it's only a town of about 60,000 with roads leading out in all directions. Wouldn't be a particularly bad disaster. Most of the population of Oregon lives about 150 miles west on the other side of the Cascade mountain range.

Misinformative

[trongey]

No, a shield volcano is formed when low-viscosity basaltic magma gradually erupts from vents or fissures. Shield volcanoes only explode when large amounts of water get involved. See http://en.wikipedia.org/wiki/Shield_volcano for a nice brief writeup.
It's only a volcano if stuff squirts out of the top.

Re:Same fault line

[keraneuology]

This is not a fault zone. Fault zones arise in response to subduction.

Not always. San Andreas is a transform fault - no subduction involved. See http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQu erry22.html

Re:Damn Hippies

[MrAnnoyanceToYou]

Dude, like, we don't need stashes around here. It's totally legal, and stuff. See? I've got my prescription card... What? Interstate commerce is affected, and therefore it's a federal jurisdiction?

Totally ruinin' my buzz.

Re:A relative of the Super Volcano at yellowstone?

[bynary]

Well, if you go much further north you'll be in Canada. Yellowstone is in Wyoming, Montana, and Idaho. To the North you have Alberta and Saskatchewan, Canada. The hotspot in Yellowstone most likely originated somewhere to the West in present-day Idaho and/or Oregon.

Re:The fallout from Yellowstone...

[Morel]

Your post seems quite authoritative and you seem to have a good grasp
of this vulcanology thing but, near the beginning, you say:

"Also, given the number of volcanos we've actually seen form (none),
and given that vulcanology is not an exact science, it would be premature
to assume that volcanos can't form rapidly."

BZZT! Wrong!We've seen Paricutin
form, in Mexico.

Cheers,

Morel

Additional technical papers on the bulge

[dtmos]

At the 98th Annual Meeting of the Cordilleran Section of the Geological Society of America (May 13-15, 2002), in Corvallis, Oregon, there were several papers on this bulge in the "Hazards and Risks from Cascade Volcanoes" session. Apparently it was discovered in April 2001; the GSA even sent out a press release about the bulge in May 2002.

Re:As an Oregon resident...

[BreadMan]

I grew-up in Maryland. Not exactly hurricane alley, but we got our share. Hurricane's don't sneak-up and surprise you; even 20 years ago, we had a few days of warning. Prepping for a hurricane involved:

1- Anything outside that couldn't be tied down was brought inside
2- We were far enough away from the coast that we just needed to secure the windows (if not tight, the wind would drive water under the sills), not cover them in wood
3- Make sure we had a several gallons of drinking water
4- Check supply of candles, matches, batteries, make sure the radio worked
5- Double check we had enough canned food/dry milk for a few days (also, locate manual can opener)
7- Fill-up the station wagon, have clothes handy if we needed to leave quickly
8- Get board games out of the closet
9- Buy ice for the freezer

Power outages typically lasted a few days. Several times, we were under a boil water order, so the drinking water came in handy. We never had to leave our home.

Notice that none of the above involved stitting around for the government to do anything.

Re:Super Volcano?

[cmjensen]

over here we don't have a history of multiple eruptions each year.

Yes, yes, you do. In 1854, Baker, Rainier, Mount St. Helens, and Chaos Crags were all active. In the same decade, Shasta and Hood were also awake. ("Fire Mountains of the West" is a good overview).

You are being deceived by the 1900s, which were unusually quiet in the Cascades with only two events St Helens (1980-99) and Lassen (1914-17). By comparison, the events in the 1800s were longer and more frequent: St Helens (1800-57), Rainier (1800-54, 73, 79, 82), Baker (1843-80), Chaos Crags (1854-57), Shasta (1855), Hood (1859, 65, 66)

Re:A relative of the Super Volcano at yellowstone?

[Anthony]

I am not an expert, but that never stopped a Slashdotter posting before ;-). Yellowstone, IIRC, is thought to be hotspot activity ie a rising mantle plume, packed full of low-viscosity short-chained silicates. The Cordillera runs along the Rockies/Andes and is formed by the subducting Pacific plate, melting continental crust and forming rising molten crust, packeed full of sticky long-chain silicates and volatiles. Different composition and different behaviour. There will be some molten crust melted by the Yellowstone mantle plume which adds to the explosive potential as well as the water near the surface adding to the volatile content of the melt.