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Science

Molehill Mountain Detected From Space 16

Posted by michael from the good-titles-make-good-submissions dept.
SEWilco writes: "A four-inch mound was detected in Oregon recently near the Three Sisters volcanoes. Unlike a molehill, it's 10 miles across and was detected by radar from a satellite. The USGS Cascades Volcano Observatory compared two radar images which were taken four years apart and produced this image of the uplift. A USGS statement says the cause is uncertain, but a new pool of magma is suspected. There are no signs of pending eruptions."
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Molehill Mountain Detected From Space More

Molehill Mountain Detected From Space

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  • The article states that this is the first time that a ground movement like this has been detected. I wonder how many radar images were created and studied before this one was discovered.

    As another reply mentions, there have been many studies of assorted other earth motions in the past. Assorted sophisticated equipment has been scattered across California and Japan for decades, along with active volcanic areas. Indeed, one of the deaths at Mount St. Helens [usgs.gov] was David A. Johnston who had taken laser measurements 90 minutes earlier. Two geologists were flying overhead when the eruption began.

  • Well, if it's a caldera we'll all want to be in Florida. Everyone this side of Europe will be displeased to be downwind of such a mess. At least with a caldera there should be a lot more warning activity than what's been seen at this site.
  • If magma is causing the bulge, it may not "sink back". If all it does is cool and harden, it just becomes a layer of intrusive rock [jmu.edu].
  • Well, I read it. I was 9 when Mt. st. Helens erupted, so I don't remember it well. Add to that my being across the country in Arkansas, and you can imagine that it had no impact on me directly. Not until I atleast saw the pictures of the distruction did I appreciate the magnitude of it, and even then not very well. It must have been a sight to see, definitely.
  • I don't mod. But if I did, you'd get a 'Funny' out of me for that one.

    Your assignment now is to draw up a movie poster for that. Maybe you can get it filmed - that's a Troma title if ever I heard one. :-)

    "Smear'd with gumms of glutenous heat, I touch..." - Comus, John Milton
  • While the statement [usgs.gov] suggests that an eruption, if it occurs, is still a ways off, I still feel kind of excited by the news. If it does turn into an eruption, we'll have been able to study the ground activity that preceeded it in detail for a significant period of time beforehand. But then again, I'm an amateur when it comes to this -- any real geologists know if we've had this kind of research opportunity before?
  • The ringed pattern makes it look more like a ripple, with crests and troughs, and seem to have been something energetic that happened that had the energy radiated outward in a circle.
  • I just hope for the sake of the Pacific Northwest that it doesn't end up being a caldera volcano like Yellowstone [usgs.gov].
  • You didn't read the text that went along with the graphic:

    Each full color band from blue to red represents about 2.8 cm (slightly more than 1 inch) of ground movement in the direction of the radar satellite. In this case, four concentric color bands show that the surface moved toward the satellite (mostly upward) by as much as 10 cm (about 4 inches) sometime between August 1996 and October 2000...

    It isn't "rippled" ground; it is a single raise in the land. The colorscheme they used is just confusing.
  • I read it too and it is one of my earliest childhood memories as I was living in (you guessed it) Spokane Washington at the time. (In case you don't believe me I was born in Sacred Heart hospitol.) I was extremely young so I don't remember much but I remember the sky being dark and ash all over the place. On the car particularly. Hope you are one of those people that checks up on your posts in your user profile. ;)

  • I think you've misunderstood -- which is easy to do given the way they represent the data. Those color bands are like countour lines on a topographical map. There is 1 cm of uplift from one red line to the next, and another 1 cm to the subsequent red line, and so on. So what you're seeing is not a set of ripples radiating out from a central impact, but is a series of lines painted on a bulge, as if someone pushed their fingers up through a balloon.
  • While the statement suggests that an eruption, if it occurs, is still a ways off, I still feel kind of excited by the news.

    Excited?? Hah! Spoken like someone who hasn't had to live through a volcano! I live about 30 miles from the Sisters, can see them out my window, and grew up in Spokane, WA. Seeing pitch black at 3pm on May 18, 1980, left me with the sense of not ever wanting to be around for another volcano blast. I think two eruptions in my lifetime would be extraordinary, eh? :)

    Anyway, the US Pacific Northwest is blessed with weather that isn't very often destructive, but the mountains, well that's another story. Still, it's better than living on the bank of the Mississippi River, that's for damn sure.

    Well, writing this two days after the article was posted makes me believe the odds of anybody reading me are slim ;-) Sorry I didn't notice it before.

  • Except (Score:3)

    by fisternipply ( 215177 ) on Wednesday May 09, 2001 @08:36AM (#235121)
    There are no signs of pending eruptions."

    Except for the giant pool of magma forming underneath the pacific northwest, that could be a sign.

  • Maybe obsolete to mention, but surfing from this article I found some nice sites about vulcanos and calderas: http://vulcan.wr.usgs.gov/Glossary/Caldera/framewo rk.html

    ---
  • Yes. Ground movement before eruptions is comonplace and well documented. Several active volcanoes worldwide have tiltmeters and laser-rangefinders mounted all over the volcano, and small uplifts / enlargements of the volcano is observed before most eruptions. (for reference see Hawaii Volcano observatory update [usgs.gov])

    similarly, in Italy near Vesuvius (which blew up in AD. 79) ground movement in the sorounding area has been observed. Particularly near the town of Pozzuli which is situated above a magma-chamber. In the last 20 years the ground has been moving mostly upwards more than a meter! so that previously sunken Roman temples once again is above the water.

    Yours Yazeran

    Plan: To go to Mars one day with a hammer!

  • According to the article, while this type of magma upswell is indicative of future eruptions, it doesn't mean there will be an eruption any time soon, if at all. It may only be a temporary thing, and sink back just as mysteriously as it popped up.

    Of course, if they're wrong and one is coming, it might be a good idea to get out of the area.

    Hmmm...Is that why Boeing left Seattle?

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