Eruptions

Chaiten eruption worsening

Chaiten 2008

The newest reports out of Chile are indicating that the eruption at Chaiten has reached levels of intensity not seen since the eruption first started over six weeks ago. I have to admit, that isn’t a good sign in terms of keeping the volcanic edifice in one piece. There have been frequent, small (<M3) earthquakes along with “rumbling noises,” which might indicates that the domes are collapsing to form pyroclastic flows. Alternately (and need I remind you, very speculatively) it might be the the edifice itself beginning to show the wear of this long eruption and the emptying of the magma chamber.

The most troubling to me is this part of the report: [The military flyover] spotted two new craters. Officials said they saw bursts of gas coming from different areas around the base of the volcano. This suggests that there is enough pressure under the volcano to start opening new vents. Whether or not this leads to the formation of a ring fracture – the series of fractures around edge of a caldera that facilitate collapse – is pure speculation, but at the very least, this is a new stage of activity at Chaiten.

Comments

  1. #1 Thomas Donlon
    June 17, 2008

    There was a newsreport at
    http://www.mcgill.ca/newsroom/news/item/?item_id=100507
    It seemed to suggest that part of the mechanism for a supervolcanic eruption (even a small one) was the collapsing of the magma chamber and that the collapse stirs up the magma more.

    Although I can see this as a mechanism for such an eruption I wonder if just the rising of magma that was pressurized from deep within the earth can cause a massive explosion – even without the prior collapse of the magma chamber. The article I read was written at a simplistic level and I don’t know how much stock to put in it.

    Do you have any further insights into this article?- particularly as it may relate to chaiten?

  2. #2 Erik Klemetti
    June 19, 2008

    I meant to comment on this sooner, but I did have a brief entry on this research that the media picked up about “supervolcanoes”:

    http://eruptions.wordpress.com/2008/05/29/when-science-journalism-goes-bad/

    Now, I don’t mean to make it seem like this research isn’t interesting – it is, just not earth shatter (no pun intended). The rocks themselves indicate that there is a lot of mixing that happens very rapidly before eruptions of this magnitude, so the rapid generation of volatiles is not a surprise. They just present another mechanism to “mix” the magmas during the eruption. Most large explosive eruptions are driven by over-pressurization of magma due to volatiles (gases) coming out of solution in the magma as it rises. The key piece of information we don’t have a grasp on is why some volcanoes will catastrophically depressurize (i.e., giant eruptions), while others will more passively lose the gases and not catastrophically erupt.

    As for Chaiten, it seems like there is/was a lot of volatiles trapped underground with the magma, and this has helped drive the explosivity of the eruption. The questions in the coming months/years will be how volatile-rich was the magma, where was it stored and how long has it been stored.

  3. #3 Stacey
    December 28, 2008

    How do I know if this is accurate , I’m alittle shaky in the facts there is not much evidence

  4. #4 Nyla Amoe
    November 8, 2010

    What a waste of time. You’re poor english made this article hard to read. Learn to write.

  5. #5 Charles Ennis
    November 24, 2010

    The moment I found your blog was like wow. Thanks for putting your effort in writing this post.

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    December 6, 2010

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