ONEMI, the Emergency Office of Chile, is expressing concerns that Chaiten might be readying an even bigger blast than what we’ve seen already in the past few months. In particular, ONEMI direction Carmen Fernández is concerned that the volcano might have a major explosion with accompanying ash fall and pyroclastic flows. They are pointing to the increased seismicity at depth under Chaiten as potential evidence that the conduit to the surface is partially blocked, and thus building pressure for a large explosion – think Augustus Gloop in Charlie and the Chocolate Factory if you want a mental picture.
Now, it is hard to tell from the evidence in the article whether this seems likely or not, but usually deep seismicity under a volcano means that magma is moving – and when magma is moving, it is usually moving upwards to the surface, which means eruption if it makes it all the way. The SERNAGEOMIN agrees with some of the ONEMI suggestions (covered nicely on the Volcanism Blog), but overall, the feeling I get from reading these reports is that the Chilean officials are playing this with an abundance of caution, and rightly they should. As I’ve mentioned, we are now in somewhat uncharted seas when it comes to historical volcanic eruptions in the modern era, so making a prediction for Chaiten’s next move is tricky business.
12 responses to “Is Chaiten a clogged volcano?”
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Brian – I think I’ve heard it is somewhere in the vicinity of a VEI 5-6 although there is some debate about the magnitude of the initial eruption. I would imagine that any new increased eruption would be in that same vicinity. It is actually pretty hard to get higher than VEI 6 without going into that Yellowstone/Toba vicinity.
As for the mountain vs. caldera, based on what I know about Chaiten, the “mountain” itself is a resurgent dome within the Chaiten caldera itself. The resurgent dome is formed by eruptions after the caldera-forming eruption, usually close to the middle of the caldera. If, for some reason, Chaiten does have a new caldera-forming eruption, then yes, likely the mountain that people are familiar with at Chaiten would likely not survive. -
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Just curious, how big approximately was the last eruption a few months ago, on the VEI scale? If this one is bigger, it could be real intersting.
Also, I understand the caldera is actually bigger then the mountain (please understand I am not a scientist). Could this eruption expand outside of the crater and even destroy the mountain that is there?
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