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  1. #1
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    Don't Plan Any Skiing at Mt. St. Helens Anytime Soon

    USGS Volcanic Unrest Statement

    http://www.geophys.washington.edu/SE...ENS/mshpic.gif
    U.S. Geological Survey, Vancouver, Washington

    University of Washington, Pacific Northwest Seismograph Network, Seattle, Washington

    Mount St. Helens Notice of Volcanic Unrest

    September 26, 2004 3:00 P.M., PDT

    Seismic activity at Mount St. Helens has changed significantly during the past 24 hours and the changes make us believe that there is an increased likelihood of a hazardous event, which warrants release of this Notice of Volcanic Unrest. The swarm of very small, shallow earthquakes (less than Magnitude 1) that began on the morning of 23 September peaked about mid-day on 24 September and slowly declined through yesterday morning. However, since then the character of the swarm has changed to include more than ten larger earthquakes (Magnitude 2-2.8), the most in a 24-hr period since the eruption of October 1986. In addition, some of the earthquakes are of a type that suggests the involvement of pressurized fluids (water and steam) or perhaps magma. The events are still occurring at shallow depths (less than one mile) below the lava dome that formed in the crater between 1980 and 1986.

    The cause and outcome of the earthquake swarm are uncertain at this time. Several causes are possible, but most point toward an increased probability of explosions from the lava dome if the level of current unrest continues or escalates. During such explosions the dome and crater floor are at greatest risk from ballistic projectiles, but the rim of the crater and flanks of the volcano could also be at risk. Explosions would also be expected to produce ash clouds that drift downwind at altitudes up to several thousand feet above the crater rim. Landslides and debris flows from the crater that are large enough to reach the Pumice Plain are also possible. Such events occurred at Mount St. Helens between 1989 and 1991.

    We continue to monitor the situation closely and will issue additional updates as warranted, whether activity escalates or returns to background levels.

    Daily updates of earthquake data and other information can be found on the WORLD WIDE WEB at URL:

    http://vulcan.wr.usgs.gov/Volcanoes/...t_updates.html

    and

    http://www.pnsn.org/HELENS/welcome.html

    UPDATE: 09/25/2004 9:30 AM PDT

    Volcanoes in the Cascade Range are all at normal levels of background seismicity, but Mount St. Helens is experiencing an increased number of earthquakes.

    Seismicity at Mount St. Helens has declined significantly since yesterday. However, small, shallow earthquakes are still occurring at above typical background rates. We will continue to monitor the situation through the weekend. This message supersedes the Information Statement below.

    U.S. Geological Survey, Vancouver, Washington

    University of Washington, Pacific Northwest Seismograph Network, Seattle, Washington

    Mount St. Helens Information Statement September 24, 2004

    10:00 AM, PDT

    Since about 2 am PDT on the morning of 09/23 an earthquake swarm has been occurring at Mount St. Helens. Through 5 P.M. PDT on 09/23 about 200 small (less than magnitude 1) earthquakes have been located at MSH, and many smaller events have also been recorded through this morning. The earthquakes are occurring at shallow depths (less than 1 kilometer, or 1/2 mile) mostly under the lava dome that formed between 1980 and 1986. Such earthquakes are common at MSH, but a swarm with this many earthquakes has not been recorded for several years, most recently on November 3-4, 2001. The cause of such shallow swarms is uncertain, but may reflect increased ground water levels with the onset of autumn rain. The probability of small steam explosions that hurl rocks a few hundred meters (yards) may also be increased during periods with increased shallow earthquakes.

    Prior to the 2001 swarm, the last period of increased earthquake activity at Mount St. Helens occurred in the spring and summer of 1998 when hundreds of earthquakes per month, most smaller than M=2, were detected at depths as great as 9 kilometers (6 miles). An intrusion of magma (or molten rock) deep under the volcano and resulting increased gas pressure in the conduit that leads to the lava dome likely caused this increase in earthquakes. The current swarm is different in that the events are typically much smaller and shallower. We see no evidence that an intrusion of magma similar to that of 1998 is underway.

    We continue to monitor the situation closely and will issue additional Updates as warranted.

    Daily updates of earthquake data and other information can be found on the WORLD WIDE WEB at URL:

    http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity

    (CVO Menu - Monthly Summaries)

    and

    http://www.pnsn.org/HELENS/welcome.html

    (University of Washington - Seismic Update)

  2. #2
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    that's odd Travel Channel just ran a special on Mount St. Helens earlier today

  3. #3
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    Trip: Cancelled.

  4. #4
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    Mt. Spurr has been doing that for like 6 months still hasn't exploded
    Its not that I suck at spelling, its that I just don't care

  5. #5
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    COOL!

    Just because there's activity doesn't mean that an eruption is eminent. I think it was 1982 when there was a load of activity near Mammoth (5+ earthquakes on the Richter Scale as opposed to the 2-2.8 they're getting right now at St. Helens), and there's been no eruption as of yet.

    These sort of volcanoes have a progression before they erupt. It's sort of like a pier over the ocean, where an eruption is akin to someone jumping off the pier. Right now, the mountain has already walked by the Pizza-By-the-Slice shop, is dawdling by the frozen banana shack, and almost certainly will walk back onto dry land before long.

    In 1982 at Mammoth, the mountain walked all the way to that stinky bait shop with the questionable hot dogs right at the end of the pier with every apparent intention of jumping off, but then turned around and went back to the Pizza-By-the-Slice shop, where it's been hanging out ever since, with the occassional jaunt over to the photo booth part way down the pier.

    In the 1970's, Mt. Saint Helens was hanging out by the banana shack pretty much. Then in 1980, it made the mad dash, sprinting by the bait shop, and jumped head long off the pier.
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  6. #6
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    Quote Originally Posted by Ubersheist
    COOL!

    Just because there's activity doesn't mean that an eruption is eminent. I think it was 1982 when there was a load of activity near Mammoth (5+ earthquakes on the Richter Scale as opposed to the 2-2.8 they're getting right now at St. Helens), and there's been no eruption as of yet.

    These sort of volcanoes have a progression before they erupt. It's sort of like a pier over the ocean, where an eruption is akin to someone jumping off the pier. Right now, the mountain has already walked by the Pizza-By-the-Slice shop, is dawdling by the frozen banana shack, and almost certainly will walk back onto dry land before long.

    In 1982 at Mammoth, the mountain walked all the way to that stinky bait shop with the questionable hot dogs right at the end of the pier with every apparent intention of jumping off, but then turned around and went back to the Pizza-By-the-Slice shop, where it's been hanging out ever since, with the occassional jaunt over to the photo booth part way down the pier.

    In the 1970's, Mt. Saint Helens was hanging out by the banana shack pretty much. Then in 1980, it made the mad dash, sprinting by the bait shop, and jumped head long off the pier.
    Terrible use of analogy on Ubersheist, 5 yards, loss of down.

  7. #7
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    Quote Originally Posted by Referee
    Terrible use of analogy on Ubersheist, 5 yards, loss of down.
    Eh... can't please all the people all of the time.

    Do you have a better analogy?
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  8. #8
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    i think you could find a way to equate it to jacking off

  9. #9
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    Quote Originally Posted by Droopy
    i think you could find a way to equate it to jacking off

    Yeah... But relating something to sex is always the easy and cheap way to go (i.e. takes less thought, and certainly less creative). Also, I guess I'm not as depraved as some...

    The truth is that I am a geonerd/engineerical type yahoo. As such, I HAVE to go with a pier analogy because it ever so slightly resembles volcanism then jism in a sort of pseudo technical way. Her's how it's a better analogy:

    First off, volcanism with regards to this type of volcano (a "stratovolcano," as opossed to a cinder cone or a Hawaii-style "shield volcano") has a gradational sequence of events prior to eruption, whereas masterbation really only has three very non-gradational events: Flaccidity, vigorous action, liquid explosion. Also, if you're on a pier, it doesn't mean that you're going to jump off of it, similar to when a stratovolcano exhibits charactoristics that indicate an eruption, it doesn't mean that it will blow. If you're jerking it.... well... you know...

    Y'all just need to get your heads out of the gutter.
    Last edited by Ubersheist; 09-27-2004 at 10:59 AM.
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  10. #10
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    Sweet.

    I visited St. Helens in early May this year and took a nice hike. Pretty impressive what mama earth unleashed on SW Washington in 1980.

    I'll see about getting some pics up of the blast area & the Toutle mudflows.
    Balls Deep in the 'Ho

  11. #11
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    Quote Originally Posted by Ubersheist
    Flaccidity, vigorous action, liquid explosion.
    Grip, pull.

  12. #12
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    There's a tree just like this from near the site where geologist David Johnston was killed manning hi spost until the very last on May 18th 1980
    http://seattlepi.nwsource.com/mounts...itlk_ridge.jpg

    I would sure hate to be in the way of even a small PF (pyroclastic flow).

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    ever read the book "Hampster Huey & The Gooey Kabloee"?
    "Have fun, get a flyrod, and give the worm dunkers the finger when you start double hauling." ~Lumpy

  14. #14
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    Quote Originally Posted by Lane Meyer
    There's a tree just like this from near the site where geologist David Johnston was killed manning hi spost until the very last on May 18th 1980
    http://seattlepi.nwsource.com/mounts...itlk_ridge.jpg

    I would sure hate to be in the way of even a small PF (pyroclastic flow).
    Yikes. I don't even wanna think about the peoples of Martinique when Mt. Pelee unloaded on them.
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  15. #15
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    What would Bernard Chouet do?

    Some time ago PBS aired 'Volcano's Deadly Warning'.

    Apparently there MIGHT be an indicator to eruption other than just raised seismic activity:

    long-period events
    Chouet: The Japanese seismologist Takeshi Minakami was one of the early people who got interested in making seismic measurements on volcanoes and finding out if he could interpret anything. The instrumentation he had was rather limited, so he was mostly interested in classifying events and establishing some kind of order in the richness of the observations. He ended up classifying seismic events based on the character of their signature as A-type and B-type events.

    NOVA: What's the difference between the two?

    Chouet: A-type events have a very characteristic signature that starts with an impulsive first arrival. These events occur when a volcano first comes alive again and magma is moving at depth. To make its way to the surface magma must create a plumbing system it can flow through. So the volcano is readjusting itself with lots of earthquakes. The A-type earthquake is the sound of rock breaking as the volcano readjusts itself to the magma movement.

    B-type events include two different types of processes, one of which is just like the A-type earthquake—it's rock breaking. The other type of process that was buried somewhere in the definition of B-type events is the long-period event. Unlike the A-type event, which reflects the brittle failure of rock, the long-period event reflects the change in flow pattern of the fluid that is being pushed through cracks.

    Once the plumbing system of the volcano is unobstructed, magma can flow freely through this plumbing, and A-type earthquakes cease to occur. In this situation, you'd see almost exclusively long-period events. What the long-period events are telling you then is how the magma is evolving as it comes closer and closer to the surface. The long-period event has a distinct signature marked by an emergent signal and then a slowly dying single dominant tone. This is the sound of fluid under pressure. This long-period event gives us the means to quantitatively measure that pressure and to track the pressurization in the volcano.
    IS THERE A TYPE B SIGNAL FOR MT. ST. HELENS?
    Last edited by cantunamunch; 09-27-2004 at 04:20 PM.

  16. #16
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    Here's a good short primer on volcano sesimology, from our friends at the Alaska Volcano Observatory.

    There's nothing quite like waking up to ground shaking and having to radio back to the lab to find out if the vent you are bivouacing on is going to erupt...especially when it's still dark for two more hours and the heli is grounded in fog 5,000 feet below...

    AVO Link - Primer on Volcano Seismology

    (Edit - Article removed due to excessively large images - follow the link if you are interested.)
    Last edited by Lane Meyer; 09-27-2004 at 04:29 PM.

  17. #17
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    Thanks, LM. On one of the sites linked in your original post I read this sentence:
    In addition, some of the earthquakes are of a type that suggests the involvement of pressurized fluids (water and steam) or perhaps magma.
    , hence my question.

  18. #18
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    Quote Originally Posted by Walter Sobchak
    Hopefully it'll blow in the background while I'm skiing Ranier!*
    *So long as no one gets hurt ...
    What are you skiing on Rainier? I'm looking for a solid partner to ski from the summit down to Nisqually bridge or other fun routes.

    drC

  19. #19
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    There's also other indicators in addition to seismology. It's been a while since I've learned about this stuff in school, but here's what I remember of the other indicators:

    • Geomorphic (landform) changes, which include but are not limited to:
      • Appearance of tension/subsidance crack
      • Appearance of physical indicators like fumoroles
      • General geometry of the land (i.e. larger-scale bulges or depressions)
      • Other things that I can't remember off-hand.
    • A series of gasses emitted from fumeroles and cracks. Generally, steam makes the earliest appearance, followed by somewhat common gasses (like sulfur), with rarer gases being emitted closer to the time of eruption.
    • Several indicators only percievable through various remote sensing techniques (like changes in the amount and intensity of radiation when compared to the naturally occuring radiation, infrared changes, and slight to substantial tempurature changes over broad areas).


    Anything else that the rest of you geonerds know about that I didn't mention or am wrong about?

    Man, this crap is fun!
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  20. #20
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    Uber, you're pretty much right on - although most of what you mentioned are proxies for activity that are precursory in nature and possibly quite removed temporally from the onset of any unrest.....

    One neat technique that's had a succesful aplication in recent years is InSAR (Interferometric Synthetic Aperture Radar), which you may remember as the technique that successfully imaged the bulge east of the Three Sisters volcanic complex in Oregon.

    Other idicators of volcanic unrest are:
    *heat flow
    *aqueous or gaseous geochemical fluctuations above background levels
    *Strainmeter fluctuations
    *Change in gas plume chemistry over wide areas (measured with a COSPEC - correlation spectrometer)

    In 2000, the first time I worked at the Hawaiian Volcano Observatory, we installed three borehole strainmeters high up on Mauna Loa (and one on Kilauea) to quantify crustal strain due to magma ingress/egress from the volcano's plumbing system(s). Althoug several of the instruments were plagued with electrical signal spikes of somewhat indeterminate origin, overall the installation was a success and we (I guess they at this point!) have been getting good data from the mountain(s). These instruments were really bad-ass - they were custom designed to be able to detect a millimeter of strain over a kilometer of distance. They went into holes 100 m deep, with tiltmeters and broadmand seismometers on top of them in the holes.

    Here's a link to more info about these strainmeters:
    Link to HVO Story in Strainmeter Installation (I'm the one int hepic of the lady with the hard hat wearing a red t-shirt logging core in the background)

    Of course Mt. St Helens is such a different system than those we were monitoring in Hawai`i, so seismic monitoing may very well be the primary means by which future eruptive activity is forecast there.

  21. #21
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    Lane - I agree that they are temporary precursors that may have nothing to do with increased volcanism, but they're indicators nonetheless. It's also true that shallow, high frequency seismic activity can have no correlation to the local volcanism, and it's just another indicator. Even low frequency earthquakes can be related to other geologic phenomenas (i.e. landslides and mass wasting events if it's at or near the surface), although they're incredibly good indicators if they're at any depth greater then a few hundred feet...or is it the other way around... High frequency quakes indicate magma and mass wasting movement and low frequency indicates tectonic displacement?? I can't remember. It's surely one of the two, though...

    I hadn't heard about the InSAR technique in particular. I graduated a few years before you, and I doubt it was out. Also, I didn't focus on volcanism when I studied geology. I tried to get more into the neotectonics/geomorph side as they relate to engineering geology. As such, I took a mass wasting class, a holocene geology class, a geomorphology class, etc. and pretty much stayed away from volcanoes. As such, I'm far from an expert in this field.

    However, I do remember them talking about using various sorts of remote sensing for volcanoes, just not that one in particular. There's no way I could dredge up from my memory the types of remote sensing the professors were talking about. It's been too long and I've killed too many brain cells since then.

    Since this is a skiing board with few other geologists around, I tried to keep the topics in laymen's terms. Therefore, I didn't mention specific techniques, like strainmeters, and I sort of lumped in data collected by them (or tiltmeters or inclinometers, etc.) into geomorphic changes.

    I did forget about mentioning changes in groundwater chemistry and measureable stress/strain (that can be measured and observed even if there is no phyiscal geomorphic changes - i.e. we don't know if things have moved, but the surrounding pressures have changed).

    Thanks! This has been a fun jog for my memory!
    Last edited by Ubersheist; 09-27-2004 at 06:17 PM.
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  22. #22
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    One last geonerd topic: Doesn't it bug you other geonerds when ski mags refer to geology? They almost always use the wrong term.

    Powder's little ditty on Marble Mountain a while back got it right. When they referred to the unusual geology there, they were referring to the rock types and compositions.

    Usually, the ski mags refer to the "unique geology" that makes the terrain at __(insert resort name here)__ so very good. A better term would be topography or geomorphology. Few skiers care what rock types comprise the mountain (the geology), but they care about the lay of the resort's land (topography or geomorphology). For example, The fact that Mammoth Mountain is underlain by tuffacious volcanoclastic basalt has little bearing on the fact that it's got some steep, narrow, formerly glaciated chutes and cirques that make for some excellent skiing.

    Ok.. now back to your regularly scheduled program...
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  23. #23
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    Gulp.

    ---------------

    Mount St. Helens Daily Update 9/27/04 7:00 PM PDT

    Seismic activity has very slowly increased throughout the day. All earthquake locations are still shallow and beneath the dome. The largest earthquake recorded in the past 24 hours has been about a M1.5 and no M2 earthquakes have been detected in the past 24 hours. Cascades Volcano Observatory (CVO) crews installed GPS equipment today to monitor any ground movement on the dome, crater floor and the slopes of the volcano. Preliminary results from a gas flight late this afternoon did not detect any magmatic gas around the lava dome.


    For past updates and yesterday’s Notice of Volcanic Unrest see past updates at: http://vulcan.wr.usgs.gov/Volcanoes/Cascades/ CurrentActivity/framework.html


    A few photographs of today’s fieldwork and of the volcano can be found on our website can be obtained from:
    http:// vulcan.wr.usgs.gov/News/framework.html

    Daily updates of earthquake data and other information can be found on the WORLD WIDE WEB at URL:

    http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity
    (CVO Menu - Monthly Summaries and Updates)

    and

    http://www.pnsn.org/HELENS/welcome.html
    (University of Washington - Seismic Update)

    -----------

    I'm kinda torn. One the one hand depending on the wind direction HR could easily get crazy amounts of ash from a sizeable eruption which would suck royally. One the other hand, fire == pretty.

  24. #24
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    Quote Originally Posted by Ubersheist
    One last geonerd topic: Doesn't it bug you other geonerds when ski mags refer to geology? They almost always use the wrong term.

    Powder's little ditty on Marble Mountain a while back got it right. When they referred to the unusual geology there, they were referring to the rock types and compositions.

    Usually, the ski mags refer to the "unique geology" that makes the terrain at __(insert resort name here)__ so very good. A better term would be topography or geomorphology. Few skiers care what rock types comprise the mountain (the geology), but they care about the lay of the resort's land (topography or geomorphology). For example, The fact that Mammoth Mountain is underlain by tuffacious volcanoclastic basalt has little bearing on the fact that it's got some steep, narrow, formerly glaciated chutes and cirques that make for some excellent skiing.

    Ok.. now back to your regularly scheduled program...

    Good points, but, in my experience of blowing edges, this does matter. For example, I ski primarily on Spatulas at Squaw, but there's no fucking way I'd take them out at A-Basin or Big Sky. Not because the snow is lighter there, but because the rocks are metamorphic and meta-volcanic, respectively. In layman's terms, there's pointy, hard rocks sticking up all over the place at both resports, whereas at Squaw, you predominately have this nice grusified granitoid soft shit (except for one notable exception - the Chimney) which mostly spalls off when impacted upon and is therefore very kind to ski bases.

    If I had the time and ther wherewithal, it'd be really interesting to do a slope/rocktype correlation analysis with a GIS at all ski areas in the western US and Canada to see if there really is a correlation between which resorts have the most chutes and amount of terrain over 30 degrees.

    Back to St. Helens - Interesting that there are increasing amounts of shallow weak earthquakes and no gas. My $ is on a dome building episode in the next 4-6 weeks to 3 months immediately precceding a 50-150% increase in RSAM (seismic amplitude) with small PFs out into the crater during dome collapse. From monitriong the eruptions of Anatahan volcano in the Commonwealth of Northern Marianas Islands when I worked at HVO this past winter, I learned that elevated RSAM is needed in conjunction with an increase in frequency of shallow, weak seismicity preceeding ash and tephra eruptions. But what the hell do I know, I'm a volcanologist who inspects driveways in Truckee so he can ski at Squaw.

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    I nominate the Referee for AOTM- Alias of the Month.

    What would an eruption do for ski conditions this year? Make it colder, warmer, or no change? Does anyone know?

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