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Thread: Crater Lake Activity

  1. #31
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    question about crater lake; I understand it is only rain and snow melt, is there any route for salts to enter? Salt stabilises by surface concentration with evaporation and then sinks. A salt profile can overcome convection and the natural turnover, but I thought crater lake to be exceptionally pure water?

  2. #32
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    Best sources I could find.

    In summary, The dissolved-solids concentration is about 80 ppm, made up mostly of silica, calcium, sodium, and bicarbonate (table 13). However, Crater Lake also contains significant concentrations of sulfate and chloride (about 10 ppm of each) not usually found in the surface water of humid mountainous regions.

    There also are areas that are iron rich and sport bacterial blooms, where the water is typically 15c warmer, indicating hydrothermal activity.

    http://www.craterlakeinstitute.com/o...logy/chem1.htm

    http://chemoc.coas.oregonstate.edu/~bobcollier/CLhydrothermalSite/

  3. #33
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    many thanks, reading through that it is clear there is a source down there and its salty nature will (or may) keep it low down. I surmise the densest water at 4 C in winter does not actually reach the bottom but falls to the salty zone. What a fascinating place!

  4. #34
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    Deep Lakes, are fascinating just on their own. It's amazing how many small but distinct areas of chemical, biological, and thermal nature form in them. Put a deep lake on top of a huge volcano, and yeah, it really sort of is like the icing on a cake.

    And you are right about the 4c water not reaching the bottom. The bottom of the lake is up to 6c warmer, then the area's above it. That's also another indication that Mt. Mazama is still Hydrothermally active. It's also the reason they are not sure it forms hydrates. The water is cool and deep enough barely for hydrates to form, but, as those hydrates form, and then settle into warmer waters at the bottom, they may actually then dissolve.

  5. #35
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    Mr. Gavin, one of my friends who is a regular lurker here informed me that some of my earlier post in this thread came off a little hostile.

    I apologize if that was what came across. I was merely distressed by the notion of the hazard a carbonated lake represents, and one so close to home to boot.

    I've always appreciated your volcanic posts and updates since you began doing them.

  6. #36
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    It didn't bother me, I'm just a amateur Vulcanologist, and not involved with USGS. Crater Lake is just one of those environmentally touchy area's. They technically could send in a lot of probes to find out what's going on quickly. But it would totally ruin the pristine nature of the lake. So I don't see that happening unless the lake chemistry starts altering subtly first. That's really how someone will know there might be a issue there that needs attention, is the lake chemistry will start to change in subtle ways. More Sulfurs, silicates, iron and copper.

  7. #37
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    3 confirmed quakes today at crater lake, the largest being only .8 mag (point 8 mag not 8.0 mag), the other two less then .1 Mag. They only showed up on 2 seismograph stations, so no percise location is posible, thus they are not on the USGS or Google map based EQ spotters.

    Examining the webicorders myself, I was able to determine the strongest and earliest seen signals were at the Wizard Island seismograph station. Then next on the Cook Cove Seismograph station inside the north rim at lakes edge. The Mt. Scott station on the south flank did not show the events.

    So best guess puts them inside the caldera someplace, likely near Wizard Island.
    Last edited by dgavin; 2013-Oct-25 at 07:23 PM.

  8. #38
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    Two more quakes today at crater lake, unconfirmed, and again on the less then .1 Mag range. These only showed up on the Wizard Island station as the other two stations were saturated by wind storm readings.

  9. #39
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    There may have been one more quake here yesterday, similar as a less than .1 Mag, however it was hard to pick out as the seimographs are saturated by wind readings, and this one is more likly a miss reading on my part. Wind saturation has continued through today, so not sure how many more updates there will be on Crater Lake. The very tiny quakes could be over with by the time the storms settle down.

  10. #40
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    There was nice looking rock slide signature on Cook Cove Seismograph station today, but it's been quiet otherwise. Don't really expect much more to report on Crater Lake in the next few weeks. The stations are still fairly wind saturated.

  11. #41
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    From USGS friday report:
    A swarm of approximately 20 very small VT-type earthquakes occurred in the southeastern part of the Crater Lake caldera over the space of about 5 hours on April 8th.

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