Eruptions

Chaiten eruption photos

Chaiten 2008

There are some astounding new pictures of Chaiten in full eruption over at the Smithsonian Website. There pictures were released by the USGS/VDAP team and show a full eruption column coming from the new dome in the Chaiten caldera (see above and below). The dome itself looks giant, filling up a lot of the old caldera (the highlands around the edge of the dome itself). The eruption is almost the antithesis of the 2004-08 Mt. Saint Helens dome eruptions which has produced a minute dome filling the 1980 crater. This rhyolite dome is the first major rhyolite eruption in almost 100 years, so I can’t understate the significance of Chaiten. Exciting stuff for those of us into silicic magma.

Comments

  1. #1 Philip_B
    July 3, 2008

    You can clearly see a dome in the old caldera on Google Earth which predates the eruption. The horizontal extent of the dome doesn’t seem to have increased in these pictures. Although, GE doesn’t give a good view of vertical height and that may well have increased.

    Also pictures a week or so back showed a new dome and vent or vents developing to one side of the existing dome, which doesn’t seem evident in these pictures.

    Otherwise, I’m interested in the experts opinion of the likelyhood that Chaiten still has the potential for a full blown plinian eruption. Krakatoa erupted for 5 months before it blew.

    Great blog BTW. Some people don’t like the colour scheme, but personally, I think it works.

  2. #2 Erik Klemetti
    July 3, 2008

    Thanks for the comment. I took a look at the Google Earth images of the pre-eruption Chaiten, and sure enough you can see the ~9000 year old dome. However, I wasn’t too sure how big that old dome is based on the image, and the steepness of the sides of the dome in the new images would suggest a lot of new material being deposited near the vents (9,000 years is a lot of time for erosion to work its magic). However, most of the material erupted has been in the form of ash, so I don’t know how much new dome has been added as such beyond the estimate from the USGS (55 million cubic meters as of June 13).

    As for the new vents/domes, my guess is that these images aren’t the freshest. I haven’t come across any pictures yet with these new vents that have been reported.

    And as for the future … well, I think right now it might be anyone’s guess. There is the potential that Chaiten might blow its top and collapse like the SERNAGEOMIN has mentioned previously. Equally likely it could continue erupting at this clip for months before petering out. Or it might suddenly just stop erupting from one day to the next. We really don’t have much to compare this to right now. Even the 1912 eruption at Katmai only lasted a few days to a week (or so we think).

  3. #3 Werner Luis
    July 6, 2008

    Erik:
    There are five pictures of the old pre-eruption dome. Look at: http://volcanism.wordpress.com/?s=dome+keller&searchbutton=go%21
    The anual rainfall there is 3000 mm. If I look at the vegetation of the “old dome” I must assume that it is no more than 300/600 years old, d´ont you think so?
    Regards,
    Werner Luis